Thoughts on Ubuntu 8.04 LTS update

Well, after using it 3 weeks on my laptop, I am underwhelmed. 7.10 was much better. Everything just worked and there were no crashes. From Firefox 3.0-beta5 which broke about 50% of my plugins, through the sudden hard locks with the Verizon cell card (the other system did not do this), to the still completely borked video driver bit.
Just try to install a Cuda graphics driver. You have to edit /sbin/lrm-video and comment out its “intelligence” as the other published methods simply do not work.

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high user load

Sorry folks, been incredibly busy for last 3 weeks. Very little time to comment on anything. Email box full of stuff I am working through. Will get back into this early this coming week.

Frightening vulnerabilities …

There was a bit of a kerfluffle last week over weak random number generators and SSL for Debian and Debian based distributions. This vulnerability made it actually easy to crack a key generated with the OpenSSL code.
Think about the basis for this risk. SSL is based upon hard to guess integers which are built out of “entropy” (the CS definition, not the physical definition) to ensure “randomness” of some sort, and then used to construct keys. These keys, which are private, are then used for encryption. The idea being that if the key generation is fed “high quality” random numbers, it is hard to guess the key, and therefore hard to decode the packets without a brute force approach.
Works well in theory.

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Benchmarking

I have been a long proponent of meaningful benchmarks. Meaningful benchmarks are those that can be used with a reasonable level of predictive power to help in sizing and other issues.
I am also a proponent of market/institutional knowledge … if you have been working in HPC for a while, you might have a clue as to how some systems run, some good design points, some really bad ideas (“hey lets run a cluster over pairs of SLIP lines”).
Well, had an amusing exchange on Beowulf list today. The person seemed put off by my pointing out that in a cluster, IO is an issue, and you need to think carefully about the IO prior to setting a particular expectation. This person doesn’t have a great deal of experience in HPC, well, none from what I can see, and was put off by my pointing out that IO performance is an issue, and you need to think carefully about how to address it.
One of the things that our customers find valuable is our experience in catching these issues, helping to align/set expectations. The last thing you want to do is to create a scalable resource, and place a decidedly non-scalable element in there at a critical point.

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