Wizzy Africa

Apple's iPad - a n00b experience

Andy — Thu, 22 Dec 2011 23:03:00 +0200

Two friends of mine recently purchased iPads - Vernon asked me, as a computer fundi, to help him out on the installation. I always think it is useful to document first-time experiences - one adapts and forgets so easily.

Old timer

I have used Linux pretty much exclusively for the last 20 years. I have a pragmatic approach to my friends who use Windows - I have followed Microsoft's offerings from Windows98 through XP - I have an XP user's understanding of the later versions of Windows.

Apple I have pretty much never used. I have never owned one, I taught people how to use the original MacDraw, but pretty much have never used it since. So, when Vernon took advantage of First National Bank's interest-free loan to buy one, and asked my to check it out, I dashed over.

Fresh out of the box at his workplace in Cape Town, battery charged.

Internet

First hurdle - registration. There are a couple of Welcome.. screens, Name, country, etc. Pretty soon, it wants to get online to talk to Apple. Well, we had no wifi in his workplace, and the GSM SIM card was a "micro" variety, so I couldn't pull one out of my Nokia and get past that.

Failure.

Strike #1 - I can't even use this thing without Internet ? Ten years ago, this country only had dialup, and that was expensive. Requiring Internet before doing even the most basic things like taking a picture, writing a note, experiment with the touch screen ?

Vernon knew what to do - buy a SIM card, load with 100Mb data (costs R50, about $8). Weekend comes around - Andy, stop over. Some trouble getting cellular data to work through Vodacom. I had internet from my netbook tethered through my phone - google, ask on forums - ah, I need to enter "Internet" as the APN for the service provider. Would Vernon have figured that out on his own ? I don't think so.

As a side note - Ubuntu Linux knows all the main cellphone carriers in South Africa, and if I choose Vodacom on Ubuntu, it knows to put "Internet" as the APN (thanks, tumbleweed).

We walk through registration, no problems. Vernon had taken advantage of a free 1 hour course at the Apple store, and came away with "iCloud". So, we must hook that up.

An iPad manual

Back up a little - let's RTFM. Where is the iPad manual ? Nothing in the box - no paper, no CD (haha - no CD player on the ultra-thin iPad). A tap on Safari, a quick google - there is the manual, as a PDF on Apple's website. Old-Skool says:- "Save the pdf on the desktop". Safari has no options for that - wtf? Seems I am indeed old-school - the iPad has no desktop. Wait a minute - the out-of-the-box iPad comes with no manual, and there is no way to save a copy locally ?? More googling - oh - I must download the iBook application, and then get the (free !) iPad user manual. Sigh - consider it done.

Strike #2 - I need internet, some savvy, a new app, and a download just to read about how this thing works.

iCitizenship

Back to iCloud - Vernon had been told at the course that he needed a "United States" designation for his iCloud registration. Seems the only iCitizenship worth having is a US one - otherwise no music downloads and app restrictions, or something. I trust the Apple store man - how to do this? More googling - you need to attempt to get a free app from the Apple store, choose "None" as a method of payment, lie about your address, lie about a US phone number.

Strike #3 - to get the full benefits of this new iPad, one has to pretend to be a US citizen. South African simply doesn't cut it. You can buy it here, but there are heavy restrictions on its use.

GSM standards

OK - nearly there with the iCloud registration. Oops - I have no data left. Yep - I have burned through 100Meg of data just to get this far. A trip to the corner store - buy R110 pre-paid airtime, pull the micro-SIM out of the iPad, delicately put it in my phone (which takes a normal size) and walk through the USSD menus to load the airtime, and convert R100 of it to data bundles. R10 left behind as voice - whoopsie. Chalk that up to Vodacom ineptitude.

Strike #4 - the iPad comes with no SMS/USSD interface to the GSM network that would allow you to recharge a pre-paid SIM for data. You must take the SIM out and do it on a phone - that may not take the same size SIM.

Apple is using GSM - iOS (the operating system) is common with the iPhone - yet Apple stripped the GSM bits out of the codebase for the iPad.

OK - now we are sorted. I am unwilling to experiment much with iCloud - I have a feeling it could gobble up all my data again if I accidentally tap "backup" or something.

Games - nope - just a Games portal - go buy one. What, not even tetris or mines ? Oh well, was not really interested anyway.

Browsing is slick and fast, some study of the manual and gestures are easy and intuitive. Some struggle with outdated concepts like stopping running applications - I was pointed to this article by my Linux User Group.

Bluetooth

OK next - will it see my Nokia phone over Bluetooth ? My phone sees the iPad - tries to pair with it - nope. The iPad never sees my phone.

Strike #5 - Apple uses standards like Bluetooth for things like external keyboards, but does not bother to implement the standards properly.

Its like they think they are so big they don't have to bother. Receive a business card from my phone via bluetooth ? Pah - you must talk via Internet please. No matter that others value interoperability, here at Apple we have our own way of doing things.

I have paired my old Nokia phone with my newish netbook via bluetooth. I can easily move photos back and forth, and without even taking my phone out of my pocket the netbook will use it as a gateway onto the net. I can see that this brand new Apple iPad will not allow me to do that - either acting as a gateway, or being able to use my phone as a gateway for the iPad (which would have got over Strike #1 if I could have reached the settings menu, which I could not).

USB

And, last but by no means least - I cannot plug a USB stick into the iPad.

Strike #6 - there is not even a physical interface for a USB stick (or drive).

Floppy disks were good in their day - but they got too small and unreliable. Snif - floppies are gone.
CD were fantastic in their day - ubiquitous for two decades, they were the workhorse of transferable media. Now they seem bulky, small, and a tad unreliable. Snif - CDROM drives are fading from the landscape.
USB disks are small, everywhere, fit on your keyring, and absolutely rule for data transfer. Even virus-writers target them, they are that convenient. The sun has by no means set on the USB thumb drive, but Apple, in their wisdom, choose not to provide an interface.

Now, that is just nasty. That was deliberate. I saw what you did there. And I am calling you on it.

And, just because of Strike #6, I am reviewing your motivations for Strikes 1 thru 5. I could have given you the benefit of the doubt over SMS, Bluetooth and Internet, but I see now this is deliberate.

Summary

The iPad lives up to its reputation as a beautiful piece of hardware. The Multitouch screen is a true Apple innovation, and is a pleasure to use. The few apps I tried seemed nice. Read about that elsewhere - it is all true. But the level of control that Apple assert over the products they sell brings the ugly out in me.

Apple - I will not be buying your products any time soon.

Whisky Live Festival, Cape Town November 2011

Andy — Sun, 06 Nov 2011 10:59:00 +0200

I went to the Whisky Live Festival in Cape Town last Friday evening - the last day of the Festival - definitely a good choice.

International Convention Centre

Emma, a visitor from Scotland, persuaded a group of us to go, and we made our way to the International Convention Centre. We got a group rate, and 12 redeemable coupons for tasting. We decided that we would specialise on the single malts - a whisky made from the product of a single distillery rather than a blend between distilleries.

The first surprise we got was that many of the stands asked for two coupons per taste, rather than the one we had been expecting. However, this did not turn out to be a problem - by the end of the evening nobody bothered asking for coupons as it was the last day.

The booth babes were gorgeous, and most seemed knowledgeable on their products.

A good early stop was made at the stand for the Whisky magazine, who issued awards for the whiskys. The gentleman on the stand said that the overall winner that year had been a Japanese whisky - but it appeared that there were no Japanese whiskys available for tasting in Cape Town, either on his stand (stocked with also-rans from the competition) or on other stands. He recommended the Independent bottlers stand as worth a visit.

I had an early taste of a Dalwhinnie - from a very impressive stand giving tastings. I learned from Emma about Speyside - one of the centres of the Scottish single malt industry.

Glen Grant

Another stand that stood out for me was the Glen Grant stand, where the very knowledgeable South African Marketing manager gave us a rundown of their products. They also had a whisky workshop, where they had three sessions explaining the process of making whisky.

I managed to get a seat in the workshop, where the white-haired gentleman explained the process - which starts very similar to beer. Malted barley is cooked and rinsed to extract the sugar - maltose, created by enzymes from the starch in the barley grain when it germinates.

The yeasts they use are different, however - the distiller's yeast can stand much higher concentrations of alcohol. The yeast is allowed to do its work, and the first distillation step produces Low wine - with alcohol concentrations up to 60%. Another distillation step is performed - being careful to skip the initial distillation products and the end distillation products, and keeping the 'heart' of the whisky.

The end result of this is a clear liquor - of quite high alcohol concentration, ready to be aged. Second hand barrels from the sherry industry are very popular, as well as Madiera wine barrels. It is this step that gives the whisky its colour and much of its taste. Scottish whiskys must be aged a minimum of three years, but can be kept as long as 21 years.

We got to taste in the workshop the Low wine (rough, strong), the 3 year, 10 year, and 12 year Glen Grant products.

Jack Daniels

I bumped into friends Ashley and Barbs there, and also made my way to the Jack Daniels stand, where I learned the differences between Bourbon Whiskey and scotch. American whiskeys all contain at least 51% of another grain, either corn, Rye, or wheat, though they also have a 51% barley product, Malt whiskey. The Glen Grant man had no nice things to say about any grain other than barley.

We tasted some nice Welsh whisky, and Ireland were also well represented. The coupon system was out of the window by the end, so most of the stands were offering free tastings.

A very pleasant evening.

Centre for High Performance Computing national meeting

Andy — Tue, 28 Dec 2010 12:28:00 +0200

The Centre for High Performance Computing in Cape Town has an annual meeting to showcase flagship projects and listen to other people's experiences at similar centres around the world.

The 7-9th December 2010 saw the Centre for High Performance Computing's national meeting held at the Westin Grand hotel in Cape Town, next to the International convention centre, CTICC.

I am contracting at CHPC, and have blogged before about it.

Dr Happy Sithole is director of the Centre for High Performance Computing (CHPC), an initiative funded by the Department of Science and Technology (DST) and managed by the Council for Scientific and Industrial Research (CSIR). He opened the Plenary session, discussing High Performance Computing and Data curation - the latter being slipped in as a target for the next big project at CHPC, a petabyte-scale database facility.

Connectivity at CHPC

I asked a question about the schedule for the SANReN network deployment at CHPC, as I see fast networking going hand-in-hand with High Performance Computing. CHPC has a gigabit fibre link to the nearby University of Cape Town (UCT), but otherwise I consider network connectivity to be pedestrian. Happy deferred to Dark Fibre Africa (DFA) who were present at the meeting, and who replied that the original deadline of February 2011 had been pushed back to June 2011.

I consider this an unsatisfactory answer - particularly as I heard that the June date is actually a drop-dead date for another project - perhaps MeerKat. You can read the SANReN project status as of November 2010 here.

Also introduced was a proposal for two separate Petabyte-scale Very Large Database (VLDB) centres - one in Pretoria and the other at CHPC Cape Town.

EPCC - Edinburgh

Gavin Pringle gave an entertaining talk on EPCC, the supercomputing centre at The University of Edinburgh. Much of the talk was devoted to industry collaboration, and the necessity of making money, with timescales and deliverables, as a reality of research in the UK.

National Center for Supercomputing Applications (NCSA)

Danny Powell of NCSA, at University of Illinois at Urbana-Champaign, gave a little history of NCSA, reminding us that supercomputing is as much about software research as it is about large hardware installations. He introduced Blue Waters, targetting a peak performance of 10 petaflops and sustained performance of 1 petaflop running a range of science and engineering codes. He downplayed it significance on the bragging list of fastest supercomputers, saying that many other national projects will probably outstrip it before it comes on line.

Computational Physics centres in Africa

Clement Onime talked about a project spearheaded by the Abdus Salam International Centre for theoretical physics to use small linux clusters of 5 to 32 nodes for High Performance Computing around Africa. Emphasis is on implementing and maintaining such clusters, and dealing with peculiarly african issues like dealing with power outages. One of the centres Clement had worked with was AUST - the African University of Science and Technology in Abuja, Nigeria. Two years ago I installed the AUST computing facility, and recruited Dayo Adewunmi and Bobby Adesuyan to manage the installation.

Operational Oceanography

I then attended a two day breakaway session on Operational Oceanography, organised by the Nansen-Tutu centre for Environmental research - named after two Nobel Laureates, Fridtjof Nansen and Desmond Tutu. The talks were focused on the development of a system for regular and consistent monitoring and data curation of in-situ monitoring, remote sensing and ocean modelling activities of African oceans. We had an evening out at Lelapa restaurant in Langa township - always excellent.

Westin Grand

the Cape Town International Convention Centre is located right downtown, and the Westin Grand did us proud with the hospitality - food was excellent and the facilities outstanding - just no free wireless internet.

Using the Centre for High Performance Computing, Cape Town

Andy — Mon, 06 Sep 2010 20:18:00 +0200

I have recently been contracting at the Centre for High Performance Computing. This is just an update on how to map the particular problem I have onto the computing cluster.

What this is not

This is not a complicated expose of a whole computer cluster co-operating on a single task.

First steps

It is an explanation of how to get to the much easier job of splitting the main task up into bite-sized pieces that can be fed independently via a job submission system called MOAB.

Task description

Each day satellites MODIS (NASA) and MERIS (ESA) do a few passes of a polar orbit over our region of interest, African coastal and inland waters. The (large amounts) of daily data arrive via a dedicated satellite link - about 1 Gig every day. They are in "swaths", about 20 or so files from 10Meg to 800Meg.

We need to keep all this input data. It is a few terabytes and growing of several years of historical data.

This needs to be processed - mostly to cut it up and combine swaths to get smaller files of country-specific data, and a PNG picture of some attributes in the country netcdf file.

So I have a python script that reads the input files, brackets them by latitude and longitude, re-grids (lossily) the data onto a north-south grid as opposed to 'along-track' delivered data, writes the netcdf and png.

Collecting the data

All the input data was on a number of other machines in the oceanography department. The supercomputer cluster has four 79 terabyte cluster drives, accessible from all nodes. The network drives are themselves a distributed network of directory nodes and storage nodes, for speed and parallel access. See LUSTRE filesystems.

Each node runs linux, and can directly access these drives. For organisational purposes, I create a heirarchy of SATELLITE/YEAR/MONTH/* and copy all the terabytes down.

Python

I will skip the off-topic but lengthy installation of python 2.6.5 on the NFS read-only share. Consider it done :)

I can now split the problem up by day, and satellite. I have a shell script that copies and decompresses a day's input files to a 'scratch' area, and feeds that days-worth of files to a python program, which processes it repeatedly for each of our Regions of Interest, dropping the output files in the same directory. It can take up to about 6 hours to process a days files - mostly spent on the regridding operation.

You can see in this png of the Western coast of South Africa two separate swaths, and artifacts caused by the regridding operation at the lower resolution edges of the swath. MODIS orbits south to north, MERIS (above) the other way. Most of the gaps are clouds over the sea at the time of the satellite overpass.

MERIS have their own file format, but provide a java program to convert that to hdf5, a more widely recognised format that has python modules for input and output. Luckily the cluster has java :)

The shell script then copies the results back to a target file heirarchy, and deletes the input files, and finishes.

Firewall

The firewall setup around the computing cluster prevents any machine in the cluster from making network connections out. When logging into the cluster, you 'land' on the login node, and from there you can ssh to any node in the cluster on its private 10.* Infiniband network. So copying the output data to the webserver must be orchestrated from outside.

MOAB

The product page talks about graphical installations and point and click, but I prefer the command line. Usually the GUI just pokes command line tools anyway, so you are closer to the metal as well as being convenient for remote use.

The submission tool, msub, takes as parameters a number of accounting switches, where to send script output (stdout and stderr), target blade classes, and a host of other things including my script.

A problem comes because I cannot pass parameters to the script on the command line. So, if I want to tell it which day to process, I have to use an environment variable.

There are ways of naming environment variables to be passed through, but now it is getting complicated. I chose to use the 'jobname' - a simple string available in the accounting switches that I can set to anything I like. I set it to the date - for instance "2010:02:29" is a leap-day.

You can embed all the msub switches (like expected job run time, feature set of target blades needed, stdin and stout) in the script itself, prefixed by "#MSUB", which is mighty convenient. so now submitting a day's job becomes

msub -N 2010:08:11 ~/bin/meris.sh

and a trivial loop will do a month.

moab is probably sniggering at me for submitting so many single-threaded jobs and nothing more complex. I may even be penalised in the queue for jobs, but it works fine for me.

Loading and unloading

It is convenient to keep all the historical input data on the cluster filesystems, and that means setting up a daily job to rsync the satellite data as it arrives down to the cluster.

Output is currently served by the MRSU webserver at http://www.afro-sea.org.za/ - and thus needs the data copied off the cluster to be served. Because of the difficulty of synchronising, I actually do the daily processing on a beefy desktop outside that is otherwise idle, just because all the network copying can be coordinated there, and I can use cron.

There is a plan to make the site more dynamic, where you could request a custom region, at which point I would consider poking the supercomputer cluster with long spoons from the webserver. First - we need users.

Users

This is a bit double-edged - probably the folks most interested in the daily information would be foreign fishing vessels :) Regardless, potentially interested parties must be made aware of this resource funded by the taxpayer.

Eavesdropping today's smartphones

Andy — Thu, 02 Sep 2010 22:33:00 +0200

There have been a number of countries, like UAE and India that have demanded access to encrypted communications of Research-In-Motion's (RIM) BlackBerry smartphones. These efforts are misguided, and unfairly target RIM's business.

Public key encryption

We need a quick primer on today's encryption. We pick the standard scenario where Alice wants to talk to Bob, and Charlie is trying to listen in.

In the old days Alice had to get a 'secret' to Bob before they can chatter. This was vulnerable because there was always the possibility that Charlie could intercept that initial exchange.

Nowadays, public key encryption makes that unnecessary. Bob can publish a (large) number, in his newspaper, or on his business card. This Bob's public key. If Alice uses some well-known, open-source software like GPG that even Charlie has, Alice can send a message to Bob that only Bob (with a second, private large number key) can decrypt.

Let us be clear. The code that does the encryption and decryption is open, available for inspection by Charlie, who may spend years with scientists and huge computers and will still never break the code. The secret to decoding the message is Bob's private key, which he has never given to anyone.

Duality of the key pair

The two keys, Bob's Private and Public key, are a dual - what is done by one can only be undone by the other. There are infinitely many of these key pairs, and when you need them they can be generated. The bigger these numbers are, the harder it is to decrypt. The numbers can be made up to any size.

They can be used for signatures too - Bob can create an email, and sign it - attach a (very big) number to that email created with his private key. Anyone, like Alice or Charlie, can verify that only someone with access to Bob's private key could have 'guessed' the number Bob put at the bottom of the Email - proving that Bob wrote it.

Secure communication protocols

Public key encryption is at the cornerstone of SSL - the secure wrapper to a number of protocols - https:// that is used to access your banking website, ssmtp for email submission, and imaps for email retrieval to name a few. It is a very well studied mathematical science - we have a pretty good idea what America's National Security Agency is able to do concerning cracking these protocols.

Blackberry phones

Research-In-Motion have two types of customers - corporate, and casual smartphone buyers that like the BlackBerry phone. For corporate customers, they install the BlackBerry Enterprise Server (BES) - a computer at their premises that interfaces to their corporate mail server and securely delivers the mail to the smartphone.

This traffic is encrypted at the BES (Alice), send over RIM's network and the public phone network (Charlie) and decrypted on Bob's smartphone - using the private key that has never left the innards of his phone. RIM corporate clients know this, and that is why they buy RIMs devices.

Snooping traffic

The only way the message could be read by Charlie is if he installed snooping software on either the BES or the phone itself. UAE tried to install at the phone, but they were outed. RIM go into exhaustive detail on the steps used to generate and exchange the keys. If this process is followed nobody except that corporation can read those messages. Especially not Charlie, RIM themselves, or the UAE or Indian government.

With proper attention to detail, SSL protocols like SSMTP and IMAPS can be made just as secure, with no possibilities of eavesdropping. RIM has just come under the spotlight because its business model is based on this security. My Nokia E71 can access my mailserver, and the traffic between the two is secured as tightly as RIM's service. What is different is that key management on my phone is too sloppy. A Corporate Nokia customer could request more strictness.

BlackBerry Internet Service

The BlackBerry Internet Service is the service non-corporate individuals get if they just buy a BlackBerry at the corner store. Depending where that server is located, and who has access to it, will entirely determine the security of the service. If Charlie controls this server, then naturally Alice and Bob can expect no privacy.

If the UAE or India lean too hard on RIM, hard enough to either control the key generation process so private keys are revealed, or the numbers representing the keys are small enough to be broken by a large computer, or if either the BES or smartphone have spyware installed, there will no longer be any reason for corporates to buy their service, and RIM will go out of business in those markets.

Security-conscious Blackberry buyers will instead buy another smartphone, most of which (with attention to detail) can be made just as secure to eavesdroppers. The government will have gained very little in snooping on someone determined to keep their privacy.

Android

Furthermore, the new Google smartphone OS, Android, is open-source. Soon individuals or companies will be able to install their own version of the same encryption software RIM uses and neither their network provider, cellphone provider or government will be able to do anything about it.

Conclusions

Perhaps India and the UAE are just going after the conveniently-packaged security-in-a-box that the casual smartphone user has been able to buy in the BlackBerry brand - and they want to at least deny that to their perceived enemies. But it is a limited solution, will not stand the test of time, and unfairly targets one company - RIM.

As a user, don't stand for this bullying by the governments. Take your privacy and security seriously. Hold companies like Yahoo and Google and Facebook and Twitter accountable for your privacy using their services, or use them understanding that it might be, and probably is, routinely snooped.

wikileaks and the twitterverse

Andy — Sun, 22 Aug 2010 17:59:00 +0200

Last month wikileaks published a large tranche of Afghan war documents, that the Pentagon doesn't like. Actually, they want it all back, if such a thing is possible in the download age.

Crowd-sourcing

This is the new 'enemy' - the indiscriminate information age. Even during the case, wikileaks gave its followers - 120 thousand and growing - a sharply-focused feed into this continually-evolving situation. Wikipedia is there to helpfully keep the permanent record, written by the crowds, not by chosen editors. We choose our own news these days - I don't read what just one editor says.

Kenya Election

I believe in free information - I host on my ftp server "statements of domestic election observers the night before the announcement of the results" in case that information were lost. I get about 100 downloads a month.

Iran

Authoritarian governments everywhere - most recently demonstrated in Iran, fear this uncontrollable melange of information - created by twitter and short urls. It is funny to see government trying to swat the fly.

South Africa

There is a proposed Media Tribunal in South Africa - with the government's motive questioned. All governments have to acknowledge that it is impossible now to control the information - perhaps they think that if they have the TV, radio and newspapers covered they have dealt with the majority of the ANC electorate. I will miss the straight-talking Desmond Tutu in the South African media.

Europe

Julian Assange is the founder of wikileaks, reportedly permanently on the move like the Cathar Perfecti. He was bizarrely accused of rape and molestation in Sweden, and equally hastily withdrawn. Even the legal system cannot keep up with this instant feedback loop.

America

America is the land of the free. It is the homesteaders, the hackers, the start of the open source movement and the tools that built Linux and the software I use every day.

Democracy

America is also proud of its democratic heritage and sees nothing wrong with exporting informed choice for the electorate onto countries whose government would prefer the old days.

It has been hard to see the hacker culture that made a lot of what is good today in a struggle with its own government. Omnipresent cameras mean that The Man already has powerful tools. But the strength of the American system is they will resolve it, if necessary by counting heads.

My first tweet

Andy — Sat, 07 Aug 2010 17:41:00 +0200

My first tweet

When I first started this blog, I started with a self-referential piece .

There I covered snail mail, fax, email, Usenet News and instant messaging (AIM and others). Since then I have been blogging, and I have stats on what people look at. My most popular posts appear to be those on Zulu weddings, and my visit to the school where One Laptop per Child was launched in Nigeria.

Since then I learned IRC, (which you see below), which is a more refined tool than the old unix "talk" where you just banged a message on their screen. I like IRC, and especially the Cape Linux Users Group IRC chatroom. A busy linux users group, where we get together once in a while, either for technical talks or Geekdinners. It is my first port of call if I am stuck on some problem to do with programming or system administration.

Facebook arrived. Facebook has a walled garden feel to it - you are writing to and for your friends, not the world at large. Its major value is connecting with old friends, like school buddies. A lot of the privacy options are slipping away as Facebook try to monetize their incredible popularity.

I am a trailing edge technology guy - 5 year old laptop is fine. This philosophy has served me well over Google Wave. But you buy new once in a while. So, I have resisted Twitter, as another rolled over version of stuff we have seen before above, but maybe it is different.

So I am blogging the IRC conversation that lead to my first tweet. Delicate temperaments might be a little surprised at the robust exchanges, but in real-time cyberspace there is a sliding line between truth and fiction, joking and seriousness. Spinach, below, is a 'bot - a program that lives in the chatroom to perform helpful things like check the weather forecast and leave people messages.

19:20 * wizzy gets a 3 minute international phone call from Kenneth Kaunda's grandson replying to http://en.wikipedia.org/wiki/User_talk:Mkaund
20:01 <&highvoltage> wizzy: wow :)
20:01 <&highvoltage> wizzy: you should tweet that
20:07 * wizzy doesn't tweet
20:07 <&highvoltage> it's about time you start.
20:08 < wizzy> highvoltage: I'm scared
20:08 <&highvoltage> that irc oneliner you posted is really cool but it will go forgotten in our irc logs.
20:08 < wizzy> I am only just getting the hang of IRC
20:09 <&highvoltage> I'm too and that didn't stop me
20:09 < wizzy> will it be remembered in tweettown?
20:10 <&highvoltage> yep, people can mark it as a favourite, they can repeat it, google can find it, it can be indexed/searched better...
20:10 <&highvoltage> just make sure Vhata follows you (at least in the beginning), and he'll be sure to tell you when you do anything kak
20:11 <&highvoltage> doing that and following some basic guidelines will turn you into a pro in no time
20:13 <&tumbleweed> joe reports that GD change has been submitted to org.za
20:47 <&highvoltage> man reflective screens suck in offices with stupid flourecent lighting
21:00 < wizzy> Spinach: twitter
21:00 < Spinach> wizzy: twitter is http://www.penny-arcade.com/comic/2008/4/23/
21:03 < wizzy> I bet Kenneth Kaunda's grandson doesn't tweet
21:59 < wizzy> highvoltage: I tweeted. Am I as hip as Vhata yet ?
22:02 * Vhata is basically one large pelvic bone
22:12 < wizzy> http://twitter.com/wizzyct
22:13 * wizzy is too much the noob to know if the hip people find out about their followers
22:13 < cocooncrash> Spinach: last tweet from wizzyct
22:13 < Spinach> cocooncrash: "wizzy gets a 3 minute international phone call from Kenneth Kaunda's grandson replying to http://en.wikipedia.org/wiki/User_talk:Mkaund" 19 minutes and 11 seconds ago, http://twitter.com/wizzyct/status/20163674522
22:16 <&highvoltage> I just realised I don't know how to favourite a tweet in twitter (identi.ca is easier like that)

Centre for High performance computing in Cape Town

Andy — Mon, 26 Jul 2010 16:49:00 +0200

Last month I started a contracting job with the Marine Remote Sensing Unit - a collaboration between the Centre for High Performance Computing (CHPC) and University of Cape Town.

I have some history in parallel processing, mostly with Inmos, a British microelectronics company that built the Transputer, a ground-breaking microprocessor of the 1980s. I had been looking for an opportunity to work at the CHPC for a while, and took the chance when an opening arrived via the clug-work mailing list run by the Cape Town Linux Users Group.

What is the CHPC ?

Supercomputers these days consist of racks of identically-configured Blades with a fast network switch connecting them together. There is also a filesystem built upon many hard drives, providing redundancy and speed, accessible over the network.

There are two clusters at the CHPC - an IBM e1350 Cluster, iQudu, consisting of 160 compute nodes and 3 storage nodes connected to 94 Terabytes of storage. There is also a Sun Microsystems cluster with 288 blades with 8 cores each and 200Terabytes of shared storage. This is an announcement of the commissioning of the Sun cluster, and here is a blog post from a Sun engineer. There is also an older IBM Blue Gene cluster, built of PowerPC ASICs.

Both clusters run x86_64 Linux, so they appear very similar. There is a certain expectation that you provide your own environment to run your application - they provide development libraries and compilation tools.

The Sun cluster is the more recent, and the one I am using. It uses Lustre as a user filesystem. The nodes boot from Flash, and the core operating system lives in 8Gig flash.

It also has a read-only NFS mount for non-critical code - as some of the 8Gig Flash is used for logspace.

What is Marine Remote Sensing?

Earth observation satellites travel a polar orbit, with some synchronisation with the earth's spin. I think it crosses the equator at the same time every day. We use, among others, data from the Envisat satellite. There have been some recent news stories here and here. The satellite images earth as it passes over, onto a linear array of sensors tailored for different frequency bands. All data is publicly available.

We can get the raw level 1 sensor data, in a dozen or so different spectral bands, or ESA will crunch a few helpful numbers that will indicate algal bloom, turbidity, sea surface temperature, vegetation etc. as in the first story linked above.

We currently use the 'pre-chewed' data (level 2), but MRSU would like to put a few years worth of southern ocean data through some new algorithms, hence the need for CHPC. A lot of the algorithms were written for northern waters, and the Benguela current has its own idiosyncrasies that might benefit from a fresh look.

This is correlated with field measurements - a research ship that goes to the areas of interest and samples the ocean for algae that produce the chlorophyll signature visible from space. That allows the level 2 data processing to more accurately reflect sea conditions.

Research at the CHPC

There is the Advanced Computing Engineering (ACE) Lab that looks at other computing technologies, like GPGPU and field programmable gate array boards. It is staffed by graduates from UCT.

How do you program a supercomputer ?

The first thing to check is to see if your problem is easily divisible into a lot of self-contained chunks. Ours is - data for one day does not affect other days except in God's scheme of things.

Then the issue comes to be how you divide, and how you instruct them each to run the same program over different data. One way is to have a lookup table keyed by the hostname of the blade computer. Another way would be to have a central allocator to farm out the work jobs to blades as they become free.

There are other more sophisticated means. Matlab has long been a favourite of the scientific community, and Matlab have a parallel licence that allows commonly used matrix math on large datasets to be distributed over the blades.

I have been using python, and its NumPy and SciPy modules. These are optimised for single processors by, for instance, having core routines for Linear Algebra and Fourier Transforms written in FORTRAN. SciPy has a huge toolbox - with sparse matrices, signal processing, information theory. Python also has the MPI interface - a standardised way across languages to distribute your code across a computer cluster.

Update

Here is a later post on using the cluster.

Kiwix - enabling offline copies of wikimedia projects

Andy — Tue, 27 Apr 2010 14:09:00 +0200

Wikimedia projects, including the flagship English Wikipedia, have been restricted in access to people with internet access. kiwix is opening that up, via its offline reader.

I have blogged before about kiwix - this article is an effort to tell other people how to do the same.

Kiwix is a cross-platform reader of zim files. Zim is an open, standardised file format to store Wiki content efficiently for offline usage. It is compressed (LZMA), with fast resolution of inter-article links. It is simple (one file), and optimised to run on really small devices like phones.

Readers available

There are two supported platforms for the reader, Windows and Linux. These are graphical, client programs that appear similar to a web browser - with a search box at the top of a display area. These readers need a zim file to read - there is a standard File->Open dialog box available top-left to allow you to choose a zim file.

On the first time you access a zim file, the reader will offer to index it, allowing you to use the search bar. This can take quite a long time, but the results are saved on disk and you do not need to do it again. On linux, these are stored at ~/.www.kiwix.org/kiwix in case you are interested. Both readers below can be downloaded from http://sourceforge.net/projects/kiwix/files/ - which I refer to as Sourceforge below.

Windows

To install the Windows reader, you will need to download it from sourceforge above - where you will find kiwix-0.9-alpha1-win.zip. You need to unzip that file under your "Program Files" directory, and create a launcher for your desktop pointing to "Program Files/kiwix/kiwix.exe"

Linux

On sourceforge you will also find a deb for the very latest Ubuntu linux 10.04 (Lucid Lynx), called kiwix-0.9-alpha2.deb. If you are running 10.04, download this file and install it with

sudo dpkg -i kiwix-0.9-alpha2.deb

It will undoubtedly complain that some or all of libicu42, libxapian15, xapian-tools, xulrunner-1.9, zlib1g, libbz2-1.0, liblzma1, libmicrohttpd5 are missing. That is fixable by running this :-

sudo aptitude install libicu42 libxapian15 xapian-tools xulrunner-1.9 zlib1g libbz2-1.0 liblzma1 libmicrohttpd5

Which will take care of those dependencies, and finish installing kiwix for you. All these packages are in the lucid repositories.

If you are running something other than Ubuntu 10.04, you have slightly more work ahead of you. I suggest that you download the source package, kiwix-0.9-alpha2-src.tar.bz2, and get the required development packages for your distribution. You will need libxapian-dev (for search), libbz2-dev, libicu-dev, liblzma-dev, xulrunner-dev, zlib1g-dev, libmicrohttpd-dev in addition to the standard development tools. If you build an RPM or other finished package, let me know and I will get the files up on sourceforge if possible.

The reader under linux is called kiwix, and you can use the File -> Open menu to find a zim file to read. It appears in Applications under Education.

Zim files

Finally, you will need a zim file as a target for your reader. Currently, kiwix has these available at http://tmp.kiwix.org/zim/0.9/ - no doubt they will move to a more permanent place later.

The files are big. Available now (April 2010) is an excellent collection of english articles, selected for school use and painstakingly checked for vandalism (thanks Martin Walker!!) as wikipedia_en_wp1_0.7_30000+_05_2009_beta3.zim. This is 30,000 articles from May 2009 and is a wonderful resource.

There are other languages available, but they have not had the same scrutiny as the English archive above. Since the associated wikipedias are smaller, these are a snapshot of the entire wikipedia - Arabic, Hebrew, Italian and Persian.

Wikimedia has other project besides wikipedia - like wikibooks, wikiversity and wiktionary that all make excellent candidates for zim files.

Server

The linux installations have another mode - a webserver, serving the zim of your choice up via http. That is how I set it up at Kwena Malapo school above. It means that on a network at a school, only one installation is necessary, and all other computers on the network can reach it as if from a website.

First, you will need to build the index. I keep the zim files in /opt/kiwix as they are so huge. I put the index files in the same directory, so to build the index for /opt/kiwix/wikipedia_en_wp1_0.7_30000+_05_2009_beta3.zim I run the following :-

export ZIM=/opt/kiwix/wikipedia_en_wp1_0.7_30000+_05_2009_beta3.zim
kiwix-index $ZIM ${ZIM%zim}idx

Then you can run the server as follows (please read ―― as double dash ) :-

export ZIM=/opt/kiwix/wikipedia_en_wp1_0.7_30000+_05_2009_beta3.zim
kiwix-serve  ――index=${ZIM%zim}idx  ――port=8080  ――daemon $ZIM

This instructs kiwix to serve the same English wikipedia with its index from port 8080 on this computer. You can then access it as http://192.168.0.254:8080/ - replace the IP address by the IP address of this computer.

Kiwix is open-source, and uses freely-available toolkits for compression, search and rendering. The zim format is optimised for use on small devices with low computing power, so you can expect to have a port onto your favourite smartphone OS in the future. And, yes, it handles right-to-left Hebrew, and arabic writing thanks to its xulrunner mozilla heritage.

Using Freeradius with Mikrotik wireless routers

Andy — Sat, 03 Apr 2010 07:19:00 +0200

I inherited a wireless setup of three Mikrotik routers in the roof of a set of office suites in Cape Town, South Africa. They were connected to an ADSL router, but the owners problem was there was no accountability on usage.

Mikrotik

Mikrotik make a number of Single-board computers, known as "Routerboard"s, and licence a proprietary operating system called RouterOS for use on these boards.

This was my first time to come across the Routerboards, and I like them. I was asked in because Mikrotik specialists in Cape Town are hard to find, and harder to schedule.

I looked around for solutions to his problem, and decided on a Freeradius installation on Ubuntu, backed up with a mysql database and Freeradius-dialupadmin as a web front end for management. I found no good documentation on a setup to handle my requirements, so I had to figure it out as I went along, and now I am writing it up for anyone else. I did find a useful article on a hotspot-style setup and another on the Mikrotik wiki, but nothing that used MAC authentication.

RouterOS will authenticate via RADIUS - Remote Authentication Dial In User Service - and 3.x versions of RouterOS will do accounting via RADIUS.

The existing setup used the (insecure) method of system identification via MAC address. It has the advantage of not requiring users to remember passwords, it just needs a list of the wireless MAC addresses.

RouterOS setup

Wireless clients need a number of things before they can use the Internet. They need an address, a default route, and nameservers. This is traditionally done via DHCP, and I saw no reason to change that. Even though the Mikrotik boxes can run a 'hotspot' - where they allocate IP addresses locally and 'NAT' the collective for the upstream routers, I decided there should be one DHCP server serving all clients.To accomplish this I bridged the wireless and wired interfaces on the Mikrotiks. The wired interface needs an IP address - I used an RFC1918 Class C network for everything. I put the Ubuntu server at 172.16.1.254, and the Mikrotik access points at 172.16.1.{1,2,3}. All the Mikrotiks need different IPs, and I also give them different names, so obviously those below will change between boxes. I had to upgrade two of the Mikrotik boxes to 3.X software as the 2.X software does not do radius accounting.

Mikrotiks have a command hierarchy - and easy help. I am using the export verb at the appropriate command level to show my configuration. I do not include default parameters, and I keep the long lines so they can be copy-pasted.

Wired interface

/ip address
add interface=ether1 address=172.16.1.2/24

Wireless interface

The wireless network also needs setup. The interface name is wlan1, it should not authenticate by default (we need it to ask RADIUS that), it must be configured as an Access Point, and it needs an SSID that laptop users can identify with.

/interface wireless
set 0 name=wlan1 country="south africa" default-authentication=no default-forwarding=no  mode=ap-bridge security-profile=default ssid=TokaiSuites2 radio-name=tokaisuites2

Bridge the interfaces :-

/ interface bridge
add name=bridge1
/interface bridge port
add bridge=bridge1 interface=wlan1
add bridge=bridge1 interface=ether1

Radius

We must instruct the wireless interface to use radius authentication and accounting, and we must tell it where to find the radius server (the IP address below). The Radius server and clients (the Mikrotik boxes) need a common secret, used to hash information in either direction. I enabled the incoming radius port, meaning that the radius server can contact the client as well. Normally the client initiates all exchanges.

/interface wireless security-profiles
set default name=default radius-mac-accounting=yes radius-mac-authentication=yes
/radius
add service=wireless address=172.16.1.254  secret=whiteroad 
/radius incoming
set accept=yes port=1700

Now we have 3 wireless access points, requesting authentication from a Radius server, allowing authenticated clients to make DHCP requests from their common wired interface, and passing accounting packets back to the same Radius server.

Radius server

I installed Ubuntu 9.10 with freeradius, freeradius-mysql, freeradius-dialupadmin, mysql, phpmyadmin and dhcp (out of repositories). I install phpmyadmin with mysql - it is an excellent database administrator. I will not cover DHCP here - suffice it to say that it is a standard setup, with 'range' set to 172.16.1.20-172.16.1.250.

The main radius configuration file is /etc/freeradius/radiusd.conf - the only change needed here is to ensure that it includes sql.conf - by default that line is commented out.

$INCLUDE sql.conf

In sql.conf, set the database type to mysql, and set a custom mysql password for the radius user.

sql {
       database = "mysql"
       driver = "rlm_sql_${database}"
       server = "localhost"
       login = "radius"
       password = "whiteroad"
       ....
}

Ubuntu has apache-style configuration directories /etc/freeradius/sites-available and /etc/freeradius/sites-enabled, and on installation two 'sites' are enabled, default and inner-tunnel. Keep it that way, and edit only /etc/freeradius/sites-available/default.

Mikrotik routers when using MAC radius authentication present the MAC address as the username with an empty password. We wish the MAC address to be looked up from the database. In /etc/freeradius/sites-available, uncomment "sql" in the "authorize" section, and comment out "pap" in the same section.

MySQL

We must now create all the necessary tables in mysql for radius to use. I am assuming mysql has been installed expressly for this purpose - if you are using mysql for other things you will know which instructions below to avoid. mysql on ubuntu comes with no root password in installation, we must create one, and that 'radius' database.

mysql -u root
mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('wizzypassword');
mysql> CREATE DATABASE radius;
mysql> quit;

From here we can use the scripts provided in /etc/freeradius/sql/mysql. Edit admin.sql in that directory to set a custom password - for this discussion I will use wizzyradius.

mysql -u root -p < /etc/freeradius/sql/mysql/admin.sql

At the prompt, use the mysql root password above - wizzypassword.

mysql -uradius -p radius < schema.sql
mysql -uradius -p radius < nas.sql

At the prompt, use the radius user password above - wizzyradius. this sets up all the radius tables, and the optional nas table.

Now to add in a user for testing. It is easiest to use phpmyadmin, but I will do it from the command line here.

mysql -uradius -p radius
mysql> insert into radcheck (UserName, Attribute, op, Value ) values ( "00:11:22:33:44:55", "User-Password", "==", "");
mysql> insert into usergroup ( UserName, GroupName) values ( "00:11:22:33:44:55", "wireless");
mysql> insert into userinfo (UserName , Name) values ( "00:11:22:33:44:55", "Test User");
mysql> quit;

With radius running, we can now test authentication with radius :-

echo "User-Name = '00:11:22:33:44:55',password=''" | /usr/bin/radclient 127.0.0.1 auth whiteroad

We are looking for a response code 2. To debug any steps with radius, stop radius, and start it with debugging.

/etc/init.d/freeradius stop
freeradius -X

If this works as above, you should be ready to test with the Mikrotiks.

Finally, let us throw freeradius-dialupadmin into the mix, to make things easier on the administration front. If you installed it above, apache would also have been installed. Symlink its configuration file into apache, like so :-

ln -s  /etc/freeradius-dialupadmin/apache2.conf /etc/apache2/conf.d/freeradius-dialupadmin.conf

and take a look at its configuration files in /etc/freeradius-dialupadmin/. The main one is admin.conf. Just showing all the changes I made below, not all the variables in the file. I also commented out all references to ldap.

general_domain: whiteroad.local
general_finger_type:
general_radius_server_secret: whiteroad
#INCLUDE: /etc/freeradius-dialupadmin/naslist.conf
# I keep the naslist in mysql
sql_server: 127.0.0.1
sql_username: radius
sql_password: whiteroad
sql_usergroup_table: radusergroup
sql_password_attribute: Cleartext-Password
general_test_account_login: 00:11:22:33:44:55
general_test_account_password:

Now, from http://172.16.1.254/freeradius-dialupadmin/ you should see the administration page, and in particular the user we added earlier. There are some useful cron scripts at /usr/share/freeradius-dialupadmin/bin/freeradius-dialupadmin.cron that I also installed to run as user radius.

If you need Mikrotik help in Cape Town, feel free to contact me.

If you see errors or anything that is unclear in my writeup here, please let me know in the comments, and I will fix it.

Zimbabwe sanctions

Andy — Fri, 05 Mar 2010 09:19:00 +0200

I was invited to participate in BBC World Service 'Africa have your say' call-in programme to discuss Zuma's request to Gordon Brown that sanctions be lifted. I was given 30 seconds very near the end of the programme, and I handled it poorly. This post is to make up for it :)

Africa have your say

I have blogged about Zimbabwe here before. The BBC programme was prompted by Jacob Zuma's official visit to the UK, and his request for the lifting of Zimbabwe's sanctions.

Gordon Brown said Britain's stance would be reconsidered only if the Zimbabwean commissions for human rights, press freedom and free and fair elections were allowed to operate unhindered.

My initial comment was that lifting sanctions now, when so little has been achieved in the year-old unity government, would send the message that ZanuPF can carry on as usual after token changes and regional (SADC) pressure.

Unity governments

I have previously talked about what I call the 'Kenyan disease' - the experiment by the African Union to fix an irretrievably flawed election by a Unity government composed of the major parties. After this was tried again in Zimbabwe, I think it can be said that the experiment is a failure.

Didymus Mutasa was at the BBC studio to answer callers and present the government line (lift sanctions. There were other invited callers to the BBC programme, in particular John Robertson, a Zimbabwean economist I have read for a few year. His single point was that Zanu-PF have reduced the size of the economy by destroying its largest industry, agriculture, and that Zimbabwe can no longer pay their way in the world. He says that the sanctions call is a ploy by Zanu-PF to blame Zimbabwe's economic woes on their traditional bete noir - the West, in particular Britain and the US.

Near the end of the programme I was added in, and asked - "if sanctions don't work, what should be done?" I fluffed the answer, as I had little time and was not expecting the question.

SADC

Sanctions have been in place for two years or more, and have not brought about the hoped-for changes, so, indeed, what should be done? After a little thought, I believe the answer must lie with the SADC - an inter-governmental organization of 15 southern African states. The most powerful country, by far, among these is South Africa, with president Jacob Zuma - the very person asking for the sanctions to be lifted.

Zuma has been lauded as a listening president. However, at some point, a president must make a decision, inevitably disappointing one of the parties. He and the SADC must acknowledge the limitations of the Unity government they foisted on Zimbabwe after the failure of the 2008 presidential elections, and recognise the ploy exposed by John Robertson.

Zanu-PF intransigence

Zanu-PF must be called to book. The MDC's call for equitable power sharing must be recognised. There is little more press freedom than a year ago - despite agreements. The same can be said for freedom of association. The arrangement was for government post to be shared equally. After the uncomfortable Unity government agreement, Zanu-PF sliced the pie. The MDC said at the time - if the pie is sliced equally, we can take either half, right? Zanu-PF scoffed at that - they knew which half they wanted.

These are all SADC problems.

Read the Guardian for another point of view.

Kiwix install at Kwena Malapo school Johannesberg

Andy — Mon, 01 Mar 2010 12:47:00 +0200

Kiwix, an offline wikipedia selection, is installed at Kwena Malapo school.

I have blogged before about creating offline copies of wikipedia for use in school computer labs that do not have internet access.

Wikimedia, the umbrella organisation behind wikipedia and other related projects, is also keenly interested in offline uses of wikipedia. From November through January, the offline taskforce had a series of IRC meetings where we attempted to answer questions relating to the use of these offline copies. We came up with four recommendations, one of which addressed schools, and another cellphones.

In conjunction with this effort, Emmanuel Engelhart made progress and could deliver me both a compressed zim database of 30000 articles (2.4 Gigabytes, including pictures) and the software, called kiwix that could read and deliver this database served by http - the standard web protocol.

There is another tool, kiwix-index, that will read this large zim database and create an index. If this index is supplied to kiwix-serve then a floating javascript search box appears, and the whole article collection can be searched.

I was asked by Mark Batchelor of the Sandton Rotary club to help him with the computer lab they installed at Kwena Malapo secondary school. This school, with principal Michael Maligana, has 800 students and operates out of simple prefab buildings close to Lanseria airport in Johannesberg. The computer lab is a converted shipping container. A new door had been put in, with four windows and roof ventilation. A network of donated computers running Windows XP and Microsoft Office had been installed.

My proposal to Mark was to install kiwix as a 'poor mans internet' - an rich information resource navigable via a browser, with hot-linked words that drill down to more articles. We all recognise this as Internet, but the principles of the information age could now be brought to a school that has no internet connectivity.

Ricardo, Mark's Windows technician, and myself travelled out to the remote farm school on a saturday, and met Michael Maligana. I commandeered one of the computers, installed Ubuntu Linux, kiwix-serve and its software dependencies, the huge zim database and its associated index for search. We networked all the computers, and set the browser home page on each to the kiwix front page.

After some networking and power hassles and four hours in the hot environment we finally got it all working. Kwena had 30000 wikipedia articles selected especially for a school environment, and was one step closer to the information age.

Update:

I wrote a blog post describing how to get the software and install it.

Jacob Zuma: president of South Africa

Andy — Wed, 03 Feb 2010 17:00:00 +0200

Jacob Zuma has made no meaningful stamp on the history of South Africa.

I have blogged about Jacob Zuma's rise to power in the ANC before.

I am reminded of Winnie Mandela's response when asked for comment about Thabo Mbeki's re-election bid in 1999 - she said he "deserved another chance". I am sorry - "deserve" is a strange modern word like "it's not fair!" - creation of a concept that did not exist 100 years ago. When running for election the more important concept is what the electorate "deserves", not the incumbent running for re-election.

I have tried hard to justify Zuma's election to the highest office in South Africa - his struggle credentials, his common touch (in contrast to his predecessor), his stance regarding Robert Mugabe to the north. Even his proud Zulu ancestry.

I have also blogged before about the Zulu culture of polygamy - Zuma is now dubbed "Africa's most famous polygamist". But his latest child, the result of an affair with the daughter of a good friend Irvin Khoza (six years his junior) means that I have lost the faith.

Where do we start ? I pick his notoriety as a father - I see nothing else of substance that he has done as president. During the ANC succession debates, Thabo Mbeki warned against the cult of personality - and reminded his comrades how hard the ANC as an organisation had tried to avoid that. Zuma has become that personality.

Let us count the children. On his official site, www.thepresidency.gov.za he is listed as having 19 children. That page was written before the latest revelations, so I will up that to 20. By all accounts, he has no children by his first wife, four by his second, five by his third, two by his fourth, two by his fifth, and two now by other women. We are still short by five.

As Nomboniso Gasa writes in the Sowetan, we expect someone who holds public office, whose salary we pay, whose children are educated at state expense, to be held to a higher standard than the common man.

He admitted to another extra-marital affair, unprotected sex, in December 2005, also with the daughter of a struggle comrade - AIDS-positive to boot. He was cleared of rape charges, with the encounter deemed consensual. Much was made in the media of a shower he took afterwards, supposedly to minimise his AIDS risk.

After that trial he admitted that he had erred by not using a condom with an HIV-positive partner. Just four years later, we note that again he did not use a condom in an extra-marital affair. In December 2009 on World AIDS day he exhorted "But that does not mean that we should be irresponsible in our sexual practices. It does not mean that people do not have to practice safer sex. It does not mean that people should not use condoms consistently and correctly during every sexual encounter." This two months after his latest child was born to Sonono Khoza.

As Patricia de Lille said, Zuma is asking people "to do as I say and not as I do".

In the course of my work with computers in South Africa, I get to see many different township schools. There are excellent schools, and others less so. The common denominator I have found is the principal - the fount of discipline at the school. A clean, tidy, motivated school environment invariably indicates the same of the principal.

South Africans need a president to be proud of, a president to emulate. They "deserve" better than Jacob Zuma.

Jazz in Cape Town

Andy — Sat, 02 Jan 2010 18:16:00 +0200

Cape Town boasts a wide variety of Jazz, with the calendar centred around the Cape Town Jazz Festival, on the 3rd and 4th April this year.

My introduction was via Monday Night Jam sessions at Swingers, which I found in late 2006. (Others have blogged about Swingers as well). Swingers can be found at 1 Wetwyn Road, Ottery - such a short road that you cannot miss it. GPS location :- 34.000936S,18.503765E as it seems I cannot add Swingers to Google Maps. In 2006 it was a cramped but busy venue, the brainchild of Kevin Harris, that had been running since about 1985. He expanded 2007, to vastly larger premises at the same address, and it even has a facebook group where you can find even more photos than the links above. My pictures are from the old location.

On Monday nights entrance is free for the Jam session. There is a large kitchen there too, and if you book ahead (recommended) they will reserve you a table. The House band kicks off about 9:30PM, but the real action starts later - I tell visitors that you will miss the best of the Jazz if you leave before midnight. So - stay late!

Another (more accessible) jazz venue is Pilano's, in Kalk Bay. GPS 34.129493S, 18.448582E. This is a stunning venue with big picture windows looking over the sea at Kalk Bay harbour. On Sunday they have a Jazz night, also with no cover charge. A friend Buddy Wells usually plays here, a noted Jazz saxophonist who studied under Winston Mankunku and I have also seen him play at Swingers. He also plays tonight with Tutu - below.

Swingers hots up considerably in the weeks surrounding the Cape Town Jazz festival, as visiting performers make their pilgrimage to Kevin's venue.

I went to a tribute performance for Winston Mankunku just before he passed away in 2009, and I went to his memorial in Gugulethu after his death. This week I went to see Tutu Puoane - another South African Jazz singer now living in Belgium - perform at Oude Libertas -just another beautiful Amphitheatre in Stellenbosch - tonight she performs at the Cape Town International Convention Centre.

Climate change and personal responsibility

Andy — Fri, 04 Dec 2009 16:23:00 +0200

The Copenhagen Climate Change conference opens next week. It is the 15th major meeting since the start at the Earth Summit in 1992 in Rio de Janeiro. Along the way we had the Kyoto Protocol in 1997 and an attempt to extend the Kyoto Protocol at the Earth Summit in Montreal in 2005.

Copenhagen

Very few of the meetings around the United Nations Framework Convention on Climate Change have produced any tangible results - but next week's conference in Copenhagen is shaping up to be a bruiser.

Undoubtedly the protesters will be there in force, throwing stones from their glass houses, pretending it is someone else's fault. Which it is, because we all need to bear the burden.

Virtual water

I like this one. Let us travel a few thousand kilometres north, to Windhoek, Namibia, and imagine ourselves at a braai on a summers evening. Pleasant thoughts. There is a beef steak sizzling on the grill, a sun setting, some locally-made lager on ice in the fridge and one in the hand.

Where did that steak come from ? How much water did it take to produce ?

This is the essence of virtual, or embedded, water. Calculations have been made that say my 1kg steak has 15,500 litres of water in it - the water the cow drank, and the water the grass needed that the cow grazed during its lifetime. By contrast, the 1kg mealies (corn) on the same braai used maybe 1,300 litres of water - a tenfold decrease.

Vegetarians consume a lot less of the world's resources.

Namibia is a dry country. What water there is goes principally to agriculture and uranium mining (a major consumer). The Uranium industry is building two de-salination plants, but those in turn are heavily dependent on South African electricity.

So importing a cow for my braai 'imports' 7 million litres of water. Not bad.

Worldmapper

Another of my favourites. Worldmapper is a site that draws a map of the world, area-distorted by any number of metrics, from Underweight Children to Life Expectancy to Books Borrowed. Check this one on Water Use for example. And have a good rummage around the other maps while you are at it.

Eat the dog ?

The New Scientist had an interesting opinion piece discussing a new book, called Time to Eat the Dog?, where they say that a medium-sized dog has about twice the global footprint of driving a Toyota Land Cruiser, and has a larger eco-print than the average citizen of Vietnam. A cat will stare down Volkswagen Golf.

Children

One of my favourite places in South Africa is Zululand, and the king's country around Eshowe. I have known a Zulu, Walter Cele there - for ten years. He has four wives and twenty children. Some of them live in the idyllic spot where he lives, but most have moved on to occupy the sprawling shanty-towns surrounding the big cities in South Africa, like Soweto, south-west of Johannesburg. Walter's comment is that his old wives get tiresome, and the new, younger one is less trouble. I am sure that is the case, and she wants children too.

I went to a wedding of Nkosi Mzimela, a prominent Zulu chief who lives on the border of the Ongoye Forest. He is Chairperson of the National House of Traditional Leaders. He was marrying his sixth wife that day. His other five wives all graced the top table. We were invited also to the wedding feast (paid for by Pick & Pay, a prominent supermarket chain, in return for his endorsement). We were seated at a table with six other zulu girls - very demure and well-dressed. It turned out these were his 'girlfriends' - they each had two children already, and two had lobola paid already.

Why should the ordinary Zulu man listen to messages like 'be faithful' and 'one partner' in the face of role models like Nkosi Mzimela ? Single-handedly the chief negates millions of Rands of AIDS advertising and messages.

Lets face it - the human race is primarily responsible for climate change.

I leave you with another worldmapper picture - Illiterate Young Women. It is rarely their fault, but population growth will not be checked without addressing this one.

Ukweshwama - Zulu bull-killing ritual

Andy — Wed, 25 Nov 2009 13:00:00 +0200

Zulu King Goodwill Zwelithini has a number of ceremonies conducted at his palace in Nongoma, his only traditionally-built palace.

Zulu ceremonies

Zwelithini, the sixth zulu king since Shaka and his brothers carved out a piece of South Africa for themselves in the mid-1800's, is the first one to have to deal with the modern media and concepts like Human Rights.

He has a bull-killing ritual, scheduled this year for December 5. He is being taken to court over the perceived cruelty to the animal concerned.

I witnessed the ceremony on 2007, and can categorically say I saw nothing like what the ASA accuses :- men pulling out the bull's tongue, stuffing sand in its mouth or trying to tie its penis in a knot. Good grief.

I visited the ceremony with, among others, an activist who was gathering information for just such a court attempt. I spoke to him about it at that time.

The ritual

The Zulu kraal is a sacred place. It is the place where the cows are kept at night - both for safety and as a means to collect their dung for use as fertiliser or building materials. Women are not allowed in the Kraal, except for a sangoma during any ceremony. A deceased family leader is often buried in the kraal.

The Zulu king has a number of palaces scattered around Zululand, but his palace at Nongoma is his only traditional palace, built as a larger version of the traditional Zulu homestead. The kraal is huge, traditionally fenced with a thick, woody fence of living trees. Inside at the top end (all kraals are built on a slope) there is a small hut used in ceremonies by the sangoma.

Boys become men

Zulus do not have a circumcision ceremony, like the Xhosas, but they do have a coming of age ceremony. We saw about 15 young men come from the small hut with the Sangoma - white painted on their faces, and wearing traditional costume. They were greeted by the king, but were obviously shit-scared.

Picking of the bull

Loudspeakers informed us that cameras were not allowed. Everyone checked the few white people there.

First, the king viewed over the bulls (technically a steer - a castrated male - but I am going to use bull here) in the kraal. He picked one out, and now it was the job of the herdsmen to single it out to remain in the kraal. The bull pretty soon figured out that all was not well - as they circled the kraal other bulls were let out, but not him. He stuck like glue to a small knot of other bulls, but was eventually separated from them.

He was quite big. He was angry. He pawed the ground. The laaities (Afrikaans for boys) assembled uncertainly. They rushed the bull, but didn't bother him. He rushed them - they ran. Some more back and forth. Then the bull hooked one of the boys and tossed him. The others rescued their comrade, but then the bull had figured out how to get out of the kraal - and did so.

Round 1 - to the bull.

Round 2

Obviously things could not remain like this, but the laaities were excused from the task - they were obviously not up to it. The bull was found again, and after half an hour was back in the kraal - tired now. They are not used to exercise. The other zulu men - older, much more numerous - came in to the kraal. The bull was no match for their number. Someone did the right thing - lifted a back leg, and tripped the animal. They sat on the beast - fifty people ? You could not see the bull. They twisted the neck until it broke.The bull was dead.

My activist friend had a stopwatch - he said the bull took 20 minutes to die.

My conclusion

A bull suffered for 20 minutes. A group of zulu boys was traumatised for life. OK - I exaggerate - but one of them at least will never forget the moment he was tossed by a bull as the king looked on. Let them have their ritual. Postscript: You might also like to read this opinion piece.

Update: The court says the ceremony can go ahead.

Offline copies of wikipedia

Andy — Wed, 25 Nov 2009 09:23:00 +0200

I have been involved for a number of years with Hilton Theunissen and the Shuttleworth Foundation and their efforts to bring computers to township schools. A part of that software suite was an offline copy of wikipedia.

Early attempts

I have blogged before about my own project Wizzy Digital Courier putting Thin Client labs down in South African classrooms. That also included a copy of the english language wikipedia.

Initially in 2003 I took the whole of the then-existing English wikipedia, installed a copy of the mediawiki software in conjunction with mysql and apache as database and webserver respectively. The whole thing was around 18 Gigabytes - quite a handful.

It worked well, but I had various complaints on the unsuitability of the material - it was a single snapshot, and had not (could not) be proofread, so it had vandalism, and quite explicit articles around sex. Oops. But - it had search, it had a vast amount of useful information on all manner of subjects.

Very soon the English wikipedia bloomed to hundreds of Gigabytes, making it completely unmanageable in terms of size. I couldn't download it, and I couldn't proof it. What to do ?

Wikipedia Version 1.0

Wikipedia has its own community of people, and among them I connected with Andrew Cates, of the SOS Children website, who came up with a selection of articles (1000 or so) as an HTML dump that he and some others painstakingly proof-read for suitability as a children's educational resource. (He has a larger article collection now). Jonathan Carter helped package this for the tuXlab installs for the Shuttleworth Foundation.

There is a lot of work to do preparing such a collection.

Which articles should be selected ?
all the article text in the HTML dump must be stripped of links to articles not in the dump
it must be proof-read
associated pictures must be incorporated

Other people became involved, in particular Martin Walker from the State University of New York at Potsdam. Systems were put in place to help on article selection. A project was started - the Wikipedia Version 1.0 Editorial Team. Articles were assessed - both for quality (from Featured Article down to Stub) and for importance (from Top to None). These assessments are placed on the article Talk page, and a robot goes through them all on a regular basis and collects the results on project pages like this and this - conveniently doing all the heavy lifting to present sortable tables of the state of all the articles.

Thus you can find Top Importance articles of poor quality, and can highlight that page for improvement. You can cherry-pick Featured Articles to add to the collection. These tools made the article selection process far more manageable.

Offline wikipedia was identified as a priority by the wikimedia foundation.

I assisted in the post-processing by writing a script that would search all the chosen articles for 'bad words' - an indication that the article has been vandalised - and then a cleanup crew has to go through these to check and possibly remove material.

Now to package all this conveniently. A French company called Linterweb came up with Okawix - all these articles and pictures packaged in a file, with a cross-platform reader to navigate the collection. Why do we need a reader ? To implement search.

Search

For many of the places we put an offline wikipedia down, it became the 'Internet' for the children in the classroom. They had no net connection, but the principles of self-paced learning, hyperlinks for tangential information, and other net paradigms made it the 'killer app' of their little school. For Internet, you need search. For a wikipedia collection of a few thousand articles, you need search. Search needs a computer - you cannot put search on a CD or DVD or USB stick.

For a standalone computer, a Reader is needed to perform this function. From a basic HTML dump, navigated with a browser, Javascript can be pressed into service, but I have found it inadequate. In the tuXlab Thin client labs, a small network of old computers is networked to a powerful server - and I want the wikipedia collection to be browsed via HTTP, and the search to be performed server-side.

Metadata

In computer jargon, this is called metadata. It is structure beyond the mere linking of articles. There is other metadata - like the Importance assessment scale. We need to extract all that metadata and place it alongside the article tree so it can be used for indexes.

On the 24th November we had an IRC meeting - an online chat between all interested parties spread around the world. Much of this was discussed - and one thing became clear - the Wikimedia foundation needs to concentrate more on the process of generating a release, rather than the end product like Okawix. That means tools to work with the Metadata, tools to package the pictures and article references in such a way they can be optional. Perhaps targeted article collections, like Mathematics, Chemistry, Africa, Oceans. Let other organisations do the work of packaging and marketing.

To allow computers to do the work - we need good metadata. Assess articles. Rugby articles are not Top importance, except in the context of sport.

I think the article collection should consist of a number of different pieces, to be incorporated as necessary.

The text of the selected articles
Pictures for those articles
metadata to support this collection
a text search index, like one created by namazu, for those tools that can use it.

Future efforts

Though a lot of effort on offline wikipedia collections is targeted at schools, and Third World, there are other target markets. One we have not really addressed yet is the cellphone as a wikipedia platform. A cellphone implies connectivity, but these days it is becoming a universal platform - a camera, a music player, a gaming box, GPS. Personally, I would like a text-only wikipedia collection of lots of articles, but only the lede paragraph - the first section of a wikipedia page that introduces the subject. It is a song by Black-eyed Peas. It is a river in Poland. That way, I can carry all of this on my phone without paying airtime.

Cellphones

Cellphones have huge penetration in the Third World. I tell tourists I take to the townships that South Africans spend their money on cellphones and hair. Maybe we should concentrate there, as much as schools ?

Update:

Okawix offline reader standardises on OpenZIM data format.

What is a racist?

Andy — Mon, 23 Nov 2009 14:57:00 +0200

Living in South Africa, this is a much-overused term, derogatory, harking back to the Apartheid era. In my opinion, it indicates a strange paucity of the English language in a very necessary area.

Let me start with a lot of my own opinions of words I have used in Africa, starting at primary school in Kenya.

kali

Aged 6, a critical, central word in our vocabulary was kali, l loanword from kiSwahili, that (like most swahili words) had broad, multiple meanings. It could mean sharp, like a knife, hot, like pepper, or quick to temper for an authority figure like a teacher. The very first thing to know about a teacher was kali or not - could you mess around in class. The kali ones would hit you.

After I moved to the UK, I found that this word had disappeared. Maybe this was not surprising, as it was a swahili word, but what was surprising to me was the concept had also disappeared - there was no equivalent word. And - teachers had changed - there were no kali teachers. Maybe I had just grown up.

Sympa

Staying in France one summer, my French improved a lot, and I discovered the word ''sympa'' - which can roughly be translated as nice, or sympathetic, but is much more accessible than that in French. It means you like the person, and they have time to listen, empathise, support. There is no English word that catches the french meaning.

Afrikaans

Since living in South Africa, I have also gained an appreciation for Afrikaans - a rough and ready working language like kiSwahili, with a lot of humour and expressiveness. I often come across Afrikaners with good english skills that are momentarily at a loss to translate some Afrikaans word into English. I don't think it is their fault - I can easily believe that English does not have that word.

Racial differences

Let us move on to words for people of a different race. We inevitably dip our toes into racist waters - but lets be robust about this - we need words for this. The Zulus have a word for a white person - Umlungu. Various people will tell you that this is derogatory, and comes from white scum of the sea, or something. But if I am walking down a road in Zululand, a child will point and say Umlungu! She simply has no other word to use to point out this unusual thing. I am Umlungu. I wear it with pride. I do not see it as a derogatory term.

USA

America has battled with this one - around black people. We are over nigger - a word white people cannot now use in any context. It is still a legitimate word for blacks talking about other blacks, where the racist angle is gone, and they just want to be derogatory - black trash. America has settled on African-American, and Black, as non-derogatory monikers.

South Africa

South Africa has its own 'N' word - kaffir - unusable in polite company by anyone. We are not quite comfortable with Black - it still sounds a bit dodgy, but it is slowly shedding those connotations. Not quicky enough though - a newspaper report will not report a black motorist - they are just a motorist. Zulu, or Xhosa - works great - but you do not always know their racial background - a Tswana would not be happy being called a Zulu, like a Kiwi doesn't like being mistaken for an Aussie.

Racist

The stage is set. Lights are on. I need a word that says I treat black people different to white people. Because I do. I try not to, in ordinary circumstances, but plain common sense says I do. Black people treat white people differently - because we are different. The girl says Umlungu!! - you can't pretend to a six year old that I am just like all the other people on the road. I have better clothes, I am not carrying things, I don't live or work there. I am different.

There are black people like me - if they walked the same road they would also get attention.

Stop the presses. Andy is a racist.

Star dictionaries

There is no other word in English that comes remotely close. Consider the english word-space as a collection of stars in the sky - bright stars, dim stars, empty areas. Afrikaans has a different set of stars - there is a big, fat, bright one that says LEKKER - a very accessible word that means tasty, nice, good, we are agreed, and a million other things. Swahili has fewer, but brighter, stars. In English there is a bright star that says RACIST. It is surrounded by a completely empty area of sky. There are no other stars even close - this one seems to have sucked all the light out of the immediate neighbourhood.

My South African friends don't like to hear that. "No, Andy - you're not a racist!" Yes, I have black friends, and No, I am not what they mean by racist. I just cannot find a good word for what I am - and that word screams at me.

Malema

The word is being bandied about a lot these days - lets pick South Africas favourite whipping boy, Julius Malema. He accuses Helen Zille of being racist, he has accused the DA of being racist, he has accused Jeremy Cronin of the SACP of being racist (despite Cronin's impeccable communist credentials in South Africa). In turn, the Young Communist League accuses Malema of racism for his attack on Cronin. Don't we have any other words ? It is all so depressing - I don't think we do. When all you have is a hammer, everything looks like a nail.

Gugulethu taxis

Andy — Sun, 01 Nov 2009 13:46:00 +0200

Toyota Cressidas are nursed into longevity serving as taxis in Gugulethu township, Cape Town.

I have blogged about Mzoli's Meat before. We went there yesterday for a birthday celebration for Lerato, and this time I made an effort to photo the ubiquitous Gugulethu taxis. In the township proper, it seems that every other car is an aging Toyota Cressida - recognisable by the square rear lights and the grille badge in front.

Invariably the Cressida is being used as a taxi - its grille badge is synonymous with the yellow taxi top light of conventional taxis. Some are in a poor state of repair, probably because of years of continual use in the townships, but most are well looked after as the owners breadwinner.

There is no taxi licensing that I can see. Taxis in Cape Town proper have recently gone through a 'recapitalisation' scheme - an exercise to take the (registered) toyota minibus taxis off the road, and replace them with larger, safer taxis.

Mzolis was busy as usual on a weekend - we had a party of ten or so. Beer you can buy at the bottle store down the road - meat is bought, braaied, and delivered in a big tin tray for all to eat.

Winston Mankunku

Last week I was also in Gugs, with Trevor Wells, at a tribute concert for Winston Ngozi Mankunku, a well-known struggle-era Jazz musician.

Arithmetic Processing using Associative memory

Andy — Tue, 06 Oct 2009 10:41:00 +0200

Associative memory is capable of performing highly parallel arithmetic computation on large datasets in constant time.

Associative memory is a type of computer memory that is accessed by virtue of its contents, not its location. Rather than saying What is the value at location 42? it says All memory locations with the value 43 please stand up.

Why is this useful, and when is it used ?

It is used whenever a fast search must be made through a list of candidates - for a CPU cache, or a fast network switch.

But if you already know the data stored there, why are you looking it up ?

							Match
D	W	?	?	?	?	?		Search term
D	R	U	N	K	E	N	-
D	W	A	R	F			*
D	W	E	L	L			*
D	W	I	N	D	L	E	*

Crossword example

The search is usually a masked search - only some of the contents are known. Think of it like solving a crossword entry - some letters are known. You put the whole dictionary into Content-addressable memory, search for the known letters in the proper position, with "Don't Care" (usually signified by X) at the other letter locations. All word locations that match are internally flagged. Some kind of resolver in the memory allows you to pick the first one, and the entire word contents are read out. The flag is cleared, and the next match is read out. In this fashion all matching words are read.

The complexity of Content-addressable memory is such that it is rarely used, and only if speed is of primary importance, as hashing algorithms and a small program can usually accomplish tasks like the crossword problem at far lesser expense (measured in chip complexity and time).

Here we have done only the most basic operation - a search. But more can be done - depending on the result of the match, we can perform other operations on the data - like, for instance, deleting all those words, or some other operation. This does not require that we read the data out - the operations are accomplished in situ in the memory.

This may not seem useful in this example, but when doing arithmetic is is.

Dynamic RAM

Regular computer memory is built as Dynamic RAM. Speed and density are the primary constraints - more speed, more bits per chip. Today's Dynamic RAM is implemented as a single transistor per bit - switching charge in and out of a tiny capacitor (charge bucket) connected to each transistor. It is a leaky bucket - it will forget the answer in less than a second, so the data must be constantly read out (a destructive read) and then written back. The memory chip usually handles this internally, but it must be given lots of little time slots every second to handle this refresh administration.

Static RAM

RAM can be built that does not require this refresh (Static RAM) but at the cost of extra transistors - perhaps 6 per bit. So, density (number of bits per chip) is dramatically reduced. But speed is often greater, and the RAM is more deterministic - there is no behind-the-scenes administration preventing full speed access to the data. Content-addressable memory is more complex still - requiring two data lines per column (to represent the three search terms - 0, 1, X) and comparison circuitry and match lines per row.

Arithmetic

								*								*								*
Result Z									X								Y								Match	Carry
0	0	0	0	0	0	0	0	0	1	0	0	1	0	1	0	1	1	0	1	1	0	1	1	0	0	0
0	0	0	0	0	0	0	0	0	0	1	0	1	1	1	0	0	0	1	0	1	0	1	0	1	0	0
0	0	0	0	0	0	0	0	0	0	1	0	1	1	1	0	0	1	0	1	0	1	0	1	0	0	0

Step	Search	Write	Comment
0	Don't care	C=0	Clear Carry
1	X[i]=0, Y[i]=0, C=1	Z[i]=1, C=0	1 bit set
2	X[i]=0, Y[i]=1, C=0	Z[i]=1, C=0	1 bit set
3	X[i]=1, Y[i]=0, C=0	Z[i]=1, C=0	1 bit set
4	X[i]=1, Y[i]=1, C=0	Z[i]=0, C=1	2 bits set
5	X[i]=1, Y[i]=0, C=1	Z[i]=0, C=1	2 bits set
6	X[i]=0, Y[i]=1, C=1	Z[i]=0, C=1	2 bits set
7	X[i]=1, Y[i]=1, C=1	Z[i]=1, C=1	3 bits set
LOOP to Step one 8 times
8	C=1	Z[i]=1, C=0	Carry

As an example of mathematics in an Associative Array, let us look at the addition of two 8 bit fields, X and Y, to be put into a 9 bit Z result field. We will use another flag field as a carry bit C.

The subscripted X, Y and Z fields are marked with i=0 in the starred field on the right. That is a total of 58 operations to do an 8 bit add - is it worth it ?

The point to bear in mind is that this addition is taking place in all locations in the Content Addressable memory - however deep that might be. It is also worth bearing in mind that none of this data exits the CAM chip - all processing is happening in situ. Much of the access delay of regular RAM chips occurs because the signals must be boosted large enough to traverse printed circuit board tracks that take it to the processor chip actually doing the work.

The example given is an 8 bit add - trivially, this can be expanded (with more steps) to any field width, any operation (like multiply, logical, or floating point operations)

We saw an extra flag field being used for Carry - typically there might be another four flag bits used for row sub-selection, or intermediate state for other operations.

There is also a resolver (mentioned earlier) to pick the first matching field, and possibly more complex hardware to set all bits between one flag and another.

Other web resources

Content-Addressable Memory Introduction by Kostas Pagiamtzis
Content-addressable memory (CAM) circuits and architectures: A tutorial and survey K. Pagiamtzis and A. Sheikholeslami
Using Content-Addressable Memory for Networking Applications By Sherri Azgomi
Altera APEX 20K Device Family Architecture Programmable logic device including CAM - optimised for lookup

Wizzy Africa

Apple's iPad - a n00b experience

Old timer

Internet

An iPad manual

iCitizenship

GSM standards

Bluetooth

USB

Summary

Whisky Live Festival, Cape Town November 2011

International Convention Centre

Glen Grant

Jack Daniels

Centre for High Performance Computing national meeting

Connectivity at CHPC

EPCC - Edinburgh

National Center for Supercomputing Applications (NCSA)

Computational Physics centres in Africa

Other presentations

Operational Oceanography

Westin Grand

Using the Centre for High Performance Computing, Cape Town

What this is not

First steps

Task description

Collecting the data

Python

Firewall

MOAB

Loading and unloading

Users

Eavesdropping today's smartphones

Public key encryption

Duality of the key pair

Secure communication protocols

Blackberry phones

Snooping traffic

BlackBerry Internet Service

Android

Conclusions

wikileaks and the twitterverse

Crowd-sourcing

Kenya Election

Iran

South Africa

Europe

America

Democracy

More Afghan War Documents

My first tweet

Centre for High performance computing in Cape Town

What is the CHPC ?

What is Marine Remote Sensing?

Research at the CHPC

How do you program a supercomputer ?

Update

Kiwix - enabling offline copies of wikimedia projects

Readers available

Windows

Linux

Zim files

Server

Using Freeradius with Mikrotik wireless routers

Mikrotik

RouterOS setup

Wired interface

Wireless interface

Radius

Radius server

MySQL

Zimbabwe sanctions

Africa have your say

Unity governments

SADC

Zanu-PF intransigence

Kiwix install at Kwena Malapo school Johannesberg

Update:

Jacob Zuma: president of South Africa

Jazz in Cape Town