RB=Roelof Brouwer, RM=Raul Miller,DM=Devon McCormick RB> What are my options for a windows based computer with the RB> main critera being fast computing of J code.
RM> The important characteristics are: RM> RM> [1] A fast CPU (currently, J uses only one CPU per process), This first point requires more consideration. Witness Devon's observations at http://www.jsoftware.com/pipermail/programming/2006-December/004273.html : DM> The big surprise is that I can run two simultaneous J sessions on my DM> laptop (real data) giving me twice the throughput! Apparently this DM> dual-core chip is really like having two processors. and DM> The biggest speed increase so far is to run on multiple machines - DM> it's coarsely parallelizable. One J instance can only take advantage of one (virtual) CPU, but nothing says your application has to be a single J instance. Besides, chip manufacturers are now skewing towards quantity, not quality. My desktop is a couple of years old, yet the market has not surpassed its clock speed (3.2Ghz). Moore's law has stalled [1]. So, a top-end PC these days is going to be multicore: you'll be paying for at least one extra "CPU" anyway. If you write J code to take advantage of that, it would transparently extend to taking advantage of multiple physical CPUs, and purchasing one might be money wisely spent. That said, if I were buying $5K worth of machine, I'd: (A) Buy a 64 bit machine & OS, (B) weight my money towards RAM volume (at the highest speed). A quick glance at dell.com [2] shows you can get a dual 3.2Ghz Xeon desktop with 8GB of RAM for about $4000, or 16GB of RAM without the second processor. But that only leaves you about $1K for disks, a monitor, and all the other necessities and niceties. Also, you may want to save some of that money for your power bills :) RM> I can't speak for planned future versions of J. I wouldn't worry about this too much; it'll be a race between the obsolescence of the computer Roelof's about to buy, and Roger's making some very significant changes to J's architecture. I believe J Software's current focus is on leveraging the 64 bit platform. -Dan [1] For the nonce? http://www.itwire.com.au/content/view/8989/53/ [2] Can someone explain the following price quotes from Dell on memory? 32GB, DDR2 SDRAM FBD Memory, 533MHz, ECC (8 DIMMS) [add $26,670] 16GB, DDR2 SDRAM FBD Memory, 533MHz, ECC (4 DIMMS) [add $14,670] ... 16GB, DDR2 SDRAM FBD Memory, 667MHz, ECC (8 DIMMS) [add $2,970] How come the slower memory is an significantly more expensive? There must be another difference, because they don't even offer a 32GB configuration of the faster memory. I can't imagine how one could get $25K worth of value out of RAM. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
