palmer@cogsci.berkeley.edu (Stephen E. Palmer) (04/27/88)
I am looking for some information about speed of data transfer from hard disks for an IBM-AT (8 MHz, 4 MB memory). I am using the AT to control real-time experiments on human vision using an AT&T TARGA-24 graphics board. A full 512 X 512 TARGA image takes about a megabyte of storage, and so speed of transferring them to the graphics board is essential for our experiments. I currently am using two standard IBM 30-MB drives. I don't know the specs on them, but the question is whether I could decrease the time required to get stored images onto the TARGA by purchasing a higher-speed, higher-performance disk for use on this machine. I am not even sure where the bottleneck is: the access time of the disk, the data transfer rate of the disk, the speed of the disk controller, or the speed of the CPU. I do know that the images take much less time to display when they are stored on RAM disk than when they are stored on the hard disk, so the currently limiting factor is unlikely to be the CPU or the rate at which the TARGA can accept data. Steve Palmer (palmer@cogsci.berkeley.edu)
bkliewer@iuvax.cs.indiana.edu (Bradley Dyck Kliewer) (04/27/88)
In article <23776@ucbvax.BERKELEY.EDU> palmer@cogsci.berkeley.edu (Stephen E. Pa >of transferring them to the graphics board is essential for our experiments. >I currently am using two standard IBM 30-MB drives. I don't know the specs on >them, but the question is whether I could decrease the time required to get >stored images onto the TARGA by purchasing a higher-speed, higher-performance >disk for use on this machine. I am not even sure where the bottleneck is: the >access time of the disk, the data transfer rate of the disk, the speed of the You might want to look at products available from Core International; 7171 N. Federal Highway; Boca Raton, FL 33431; (305) 997-6055. They have fast drives (down to 15ms, I believe) and ESDI controllers (which operate at 10 Mbits/sec instead of 5). I haven't timed the combination, but I have used it and it makes a significant difference. You should also try a disk optimizing program (if you haven't already). Fragmented disks can run very slowly. Bradley Dyck Kliewer Hacking... bkliewer@iuvax.cs.indiana.edu It's not just an adventure It's my job!