ohrnb@edstip.EDS.COM (Erik Ohrnberger) (03/09/90)
Does anyone have any experience with a Perstore disk controller cards? As I understand it, Perstor has developed a method to greatly decrease the diskspace that is needed for each byte of information, thusly increasing the density, with a matching increase in throughput. What sort of controller card does it look like to the host CPU? Or does it matter? I know that other MFM controllers usually top out 5.0 Mb/sec, ESDI usually delivers 10-15Mb/sec, and SCSI between 7-15 Mb/sec. How does Perstor achieve 9 MB/sec? and how reliable are the units? (how long do they last? MTBF) Are they compatible with Xenix? Any information would be greatly appreciated, Erik. -- Erik Ohrnberger Work: uunet!edsews!edstip!ohrnb 2620 Woodchase Court Home: sharkey.mi.org!nucleus!echocen!erik (preferred) Sterling Heights, MI 48310
larry@nstar.UUCP (Larry Snyder) (03/09/90)
In article <868@edstip.EDS.COM>, ohrnb@edstip.EDS.COM (Erik Ohrnberger) writes: > > Does anyone have any experience with a Perstore disk controller > cards? > > As I understand it, Perstor has developed a method to greatly decrease > the diskspace that is needed for each byte of information, thusly > increasing the density, with a matching increase in throughput. > > What sort of controller card does it look like to the host CPU? Or > does it matter? I know that other MFM controllers usually top out > 5.0 Mb/sec, ESDI usually delivers 10-15Mb/sec, and SCSI between > 7-15 Mb/sec. How does Perstor achieve 9 MB/sec? and how reliable are > the units? (how long do they last? MTBF) Are they compatible with Xenix? > Bag of worms - stay clear of the PS16 controllers from these guys. First throughput on these boards is not much better than a "standard" controller with coretests of around 290kb/sec best. With the current crop of 1:1 MFM controllers available producing throughput in the 500kb/sec range and the 1:1 RLL in the 680kb/sec range - the thoughput is slow. No drives are certified for use with this controller. Miniscibe, Seagate, Priam - none of these companies support the use of these controllers on their products. Several vendors actually claim that pushing the drive to the limits of the Perstor controller will actually void the warranty. Several friends of mine actually had problems with the Perstor controllers actually ruining a drive. Bad sectors start showing up after anywhere from 3 - 8 months of use on a regular basis. After a time the drive refuses to boot - and has to be sent in for repair. I consider it better (for me a least) to spend more $$$ and get something that runs within specifications. -- The Northern Star Public Access Unix Site, Notre Dame, Indiana USA uucp: iuvax!ndmath!nstar!larry internet: larry@nstar USR HST 219-287-9020 * PEP 219-289-3745 * Hayes V9600 219-289-0286
pmartin@psmsd.UUCP (Paul Martin) (03/13/90)
In article <868@edstip.EDS.COM>, ohrnb@edstip.EDS.COM (Erik Ohrnberger) writes: > > Does anyone have any experience with a Perstore disk controller > cards? > I am using a Perstor with a seagate 4096 80 meg and it works great! This combination gives me approx 146 megs. The card acts like an RLL by putting 31 sectors per track as opposed to 17 with an MFM on a seagate 4096. On a 20 mhz 386 I can only use a 3:1 interleave giving me throughput of 360k a second. A standard MFM on this machine uses a 2:1 interleave getting 260k a sec transfer rate (according to spinrite). As you can see, the card is superior to a standard MFM or RLL controllers. If you are going to use Xenix, be sure to get the 16FN perstor. This is an AT style hard/floppy controller for networks. The only caution I have is make sure that your case for the drive has good ventilation. The perstor will cause your drive to get hotter than normal thus causing a failure. This is because the drive spins faster under the perstor. I ran into this problem after having my drive fail. I moved it to an external case and it has work flawlessly ever since. My mini tower case has a poor design for allowing good circulation of cool air. I also have a full complement of boards and memory. A friend of mine is using 2 perstor controllers (1 in an AT and the other in a 386) with 2 seagate 4096 drives hanging off of each controller. He has never had a problem, and he bought his first perstor over 2 years ago. Also be aware that the controller is not an MFM or an RLL so programs like the new spinrite II don't like it. This is the only package that I know of that doesn't like the perstor. You can even low level format with disk manager when using a perstor. I am running both Xenix/386 and dos 3.3 with no problems at all. > 7-15 Mb/sec. How does Perstor achieve 9 MB/sec? and how reliable are I guess you would need a 33mhz or faster machine to be able to use 1:1 interleave. I for one have never seen a perstor do 9mb/sec. I hope this helps! -- +--------[ Paul Martin at P.S.M. Software Development ]--------+ | Smart: pmartin@psmsd.UUCP | "Yes I am serious, and don't | | Dumb: ...uccba!psmsd!pmartin | call me Shirley!" | +-------------------------------+------------------------------+