Re: [ccp4bb]: Choice of OS platform for (bio)crystallographic computing

[David Gohara]

Hi All,   First a shameless plug about MacResearch.  For those of you who took part in our survey (and there were a good number of you), the results have been posted online and answers to the questions from our meetings are also posted in my final report.   http://www.macresearch.org   Some things there are public answers for, some things I couldn't say or can't comment on. The crystallography demographic was definitely well represented.  Thanks! One drawback of the Apple products: you are restricted to the few products they support, so you might not be able to pick & choose your graphics card. You can expect the one they sell you to be supported very well though.   This is an issue (especially with regard to stereo support) and as I mentioned in the report above, I've been very vocal about more options. Hopefully there will be more options in the future. The current card is too expensive and given that stereo hardware support doesn't work in all cases (i.e. X11, see the report for more information) is a big issue. But the situation will hopefully be resolved soon. Dial boxes: I wish someone would build & sell a USB dial box. It's so <CENSORED> obvious. The technology is very simple: 8 rotary optical counters in a box with a USB microprocessor. Design it well and you wouldn't even need a separate power cord, you could power it off the USB bus. The biggest impediment is probably the small market.   We actually looked into building and designing our own before I wrote the library to interface current dials boxes with OS X based systems.  The end result after speaking with people at Apple (not that they were going to build it, one of the evangelists was just discussing implementation details) and a few peripheral companies was that it isn't worth it (although everyone I spoke with say the value in it). The estimates were that at least 100,000 units needed to be sold for it to be justifiable given the price point people would want. I don't think there is that type of market demand. My Macintel iMac runs Mosflm 3x as fast as I would expect on processor speed alone, (compared with g77/gcc on PPC Macs) - I guess this is something to do with the dual core chip. It also runs the PPC copy of Mosflm at the same speed as I'd get on an equivalent speed PPC Mac (this is through Rosetta).   The new processors in the Intel Macs handle general purpose scalar code quite well (compared to the PowerPC). My general observation (clock for clock, which isn't terribly valid) is that scalar code typically is 2-5x faster on the new CPU's (compiler dependent) relative to PowerPC.  SIMD aside (which SSE doesn't even compare) the new CPU's are fantastic (again for general scalar code).   Regards, Dave David W. Gohara, Ph.D. Harvard Medical School (actually on vacation :) http://www.sbgrid.org