allred@ut-emx.UUCP (Kevin L. Allred) (07/25/89)
I still need to get the hard disk/controller summary ready that I promised to prepare a couple weeks ago, but in the mean time, I bought an ST02 (SCSI adapter with flopy dirve controller) and ST296N (84 MB 28ms SCSI). I played with formating it for a few hours on my 16 MHz 386sx, and I found that I couldn't get it to do do 1:1 interleave at 16 MHz, but it would do 2:1 interleave just fine even running at 8 MHz. The motherboard runs the bus at 8 MHz regardless of CPU speed. I had the 0WS jumper enabled, and the ST02 BIOS is 2.00 (Seagate says that BIOS 3.00 will be out 'really soon now' -- they didn't say wheather it would improve performance, but they did say that it would recognize 7 SCSI peripherals). I haven't played with all the permutations to see if I could somehow get it to run with 1:1 interleaving -- if someone else has gotten it to run with 1:1 interleave post the info, so that the rest of us will know what to try (if the info is, run your bus at 12 MHz, then many of us are out of luck). In the mean time, I am satisfied with the 2:1 interleave -- I have lots of memory for disk caching. Low level formating and verifying took <15 minutes with 2:1 interleave thanks probably to the bad block smarts being in the drive and not the controller. As for performance: CoreTest says: Transfer rate: 450 KBPS Average Seek: 30 ms Track-track: 10 ms Spintest says: Transfer rate: 522,240 BPS Common Sense says: 2 revolutions at 3600 RPM to read 34 (512 byte) sectors = 17 KB / (1/30 sec) = 510 KBPS = 522,240 BPS. (This by the way is the same speed as an MFM drive running with 1:1 interleave, but only 65% the speed of a 1:1 interleave RLL drive.) Obviously the folks who are getting >900 KBPS are running with a 1:1 interleave. The cost for this set up was $531, including ST296N, ST02, SCSI cable, AT floppy cable, and Disk Manager software, but not drive rails. I got it from "Treasure Chest" (800)-245-3040 -- see their add in the July Computer Shopper. I ordered Friday, and the drive arrived Tuesday (UPS). Beyond good prices, I don't know anything about "Treasure Chest". -- Kevin Allred allred@emx.cc.utexas.edu allred@ut-emx.UUCP