Xref: utzoo comp.sys.amiga.tech:6089 comp.sys.amiga:36470 Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!sun-barr!cs.utexas.edu!uunet!van-bc! From: lphillips@lpami.wimsey.bc.ca (Larry Phillips) Newsgroups: comp.sys.amiga.tech,comp.sys.amiga Subject: Re: Pal, Jr. HD controller info needed Keywords: SCSI 2090 Harddrive Message-ID: <613@lpami.wimsey.bc.ca> Date: 6 Jul 89 17:11:05 GMT Lines: 37 To: van-bc!rnews In <1492@ethz.UUCP>, visinfo@ethz.UUCP (VISINFO Moderators) writes: In <1492@ethz.UUCP>, visinfo@ethz.UUCP (VISINFO Moderators) writes: >In article <727@orbit.UUCP> baxt@pnet51.cts.com (Bill Backstrom) writes: >>>In article <292@titan.tsd.arlut.utexas.edu> lofaso@titan.UUCP (Bernie Lofaso) >>writes: >>>>I have a PAL, Jr. expansion chassis for my A1000. This unit has what is >>>>essentially a 2090 hard disk controller on a Zorro I form factor. I'm using >>>>it with an ST506 interface (a Seagate ST225 disk). Although I have been >>>>happy with the unit, after running DiskPerf I found that I was actually >>>>getting pretty slow transfer rates - about 50k/sec. My disk is formatted >>>>with the FFS and is running 1.3. I have read postings of much higer >>>>transfer rates... > >I don't know if you could speed up ST506 drives. The ST506 standars is much >slower than SCSI. So I my utilities will only work with SCSI drives. >Sorry, but this IBM standard is really to bad to use it for professional >usage on the AMIGA. A common misconception. An ST506 drive transfers data at a rate of 5 Mbits/second if it's MFM, and 7.5 Mbits/second if it's RLL. The final effective speed of data transfer into the computer is a function of the controller used, up to the maximum speed of the ST506 drive itself. The upper limit on an MFM ST506 drive (assuming 17 sectors/track), is about 510K bytes/second (522240 bytes/second) (60 revs/second * 17 sectors/revolution). Don't judge the speed/suitability of an interface solely on the implementations you have seen. -larry -- Van Roy's Law: An unbreakable toy is useful for breaking other toys. +----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca or uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 | +----------------------------------------------------------------------+