davidsen@steinmetz.ge.com (William E. Davidsen Jr) (05/13/88)
I have a system which needs a bit more disk. One possibility would be to
use an RLL controller, the other to place a full height disk externally
to replace the half height currently in use. For controllers I would get
the Adaptec 2732 (1:1 RLL) or the WD1006 (1:1 tk buf MFM).
The disks I have are ST4096 (80 MB formatted) and ST251 (42MB
formatted).
I have heard all sorts of rumors about using normal disks with RLL,
ranging from "unreliable" to "melts the coating off the disk." Has
someone already *tried* this who can give me some real info. The only
hard data I have is my local clone maker who tried this with the ST225
(super slow 20MB) who reported "every f***ing one of them stopped
working after about two weeks."
Obviously it would be cheaper to put in one really big disk rather than
replace the ones I have.
Reply by mail or post as pleases you.
--
bill davidsen (wedu@ge-crd.arpa)
{uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -meg-thaler@gumby.cs.wisc.edu (Maurice Thaler) (05/14/88)
I have recently ordered and am waiting for an ARLL card from Perstor out of Scottsdale AZ. This is a new 16bit controller for AT's and 386's which is supposed to run w/ any hard disk which you could normally use with your machine. It also has support for the >1024 cylindar disks. They have two versions of this unit one of which has RAM on the card to perform caching to improve the data transfer rate. According to the stats from CORETEST2.7 my hard disk (ST 4096 80Megabyte) gets about 250k/sec with a standard WD control card. The tech at Perstor said that in my 386, I can expect to get a transfer rate close to 2000k/sec with this new card and the size will be 1.9x or aprox 150 meg. I know that many BBS's around the country have been using this company's earlier efforts (they have an 8bit card which works in XT's and AT's) for extended periods of time without many complaints. I am using one of these older cards on a BBS I run and so far it has been trouble free. I am using this older card w/ an ST251-1 40meg (now 76Meg). This is NOT an RLL approved drive but has been one of the most popular drives to use with the earlier Perstor card. They give a drive table in the install manual that lists quite a few different head/cylinder counts and the will apprently burn custom rom's for unusual drives. I think that the new 16bit card would be much more universal since it is not dependent on its rom, you can use the CMOS configuration that comes w/ your AT. I asked the tech about all the concerns about abusing drives will RLL cards. He said that many RLL cards apply data at a higher frequency (I might be misquoting him a little) on both the pre-comp and the actual data tracks, but Perstor used a different technique which does not use the higher frequency on the data tracks and is generally as gentle to your drive as a WD control card. I have seen very little press about this board but I know that many BBS people are enthusiastic about this product. The 8 bit card takes up an extra slot on your machine and can control two hard disks (they can be different types). The sixteen bit cards REPLACE your WD control card and handle 2 floppies as well as two hard disks (and I have heard that it might be possible to run two of these cards so you could have 4 hard disks and 4 floppies!) I am awaiting this new card which has been delayed in shipping since it is a first run edition. When I called last, the cards were back from Taiwon or where- ever they were being printed, and they were being popualated here and will ship around June 1. I will run it through its paces in my Dell SYSTEM 310 and try to report to the net how it works. I am not into advertising for Perstor, but I do like the idea of inovation and this product seemed interesting to me. I do a lot of desktop publishing and need all the space I can get (I have almost 30 Meg of soft fonts!) as do most other heavy computer users I know. This will not give the performance of an ESDI drive since the access time is not increased, but a high data transfer rate is very useful if you are reading many contiguous files (such as soft fonts , image files etc which DTP people use). The price of a 4096 w/ this card gives 150Meg at about half the price of the ESDI equivalent. You can't fight the 28ms access time, but the high data transfer rate is appealing. The data is place in 31 sectors instead of the standard 17 sectors used by MFM.
pete@octopus.UUCP (Pete Holzmann) (05/15/88)
In article <10831@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes: }I have a system which needs a bit more disk. One possibility would be to }use an RLL controller, the other to place a full height disk externally }to replace the half height currently in use. For controllers I would get }the Adaptec 2732 (1:1 RLL) or the WD1006 (1:1 tk buf MFM). Try Adaptec 2372? }The disks I have are ST4096 (80 MB formatted) and ST251 (42MB }formatted). I've used both the ST251 and the St251-1 for a while without trouble. Both the St251 and 4096 are recent designs using plated media. If it works well to begin with, I wouldn't expect any trouble. }I have heard all sorts of rumors about using normal disks with RLL, }ranging from "unreliable" to "melts the coating off the disk." Has ^^^^ could be, ^^^^^ *silly*!!! depending on drive/ctrlr. }someone already *tried* this who can give me some real info. The only }hard data I have is my local clone maker who tried this with the ST225 }(super slow 20MB) who reported "every f***ing one of them stopped }working after about two weeks." Sounds about right for the ST225, a cheapo drive if there ever was one. (But hey, they've sold a zillion! I can't knock success!) } bill davidsen (wedu@ge-crd.arpa) One last thought on using RLL: If you want to make SURE that you won't get in trouble with it, get a disk-format-renewer program. Disk Technician is one; SpinRite is the best I've seen, is cheap ($60?) and getting better. If you run SpinRite once a month, it will re-do your low level format without requiring a backup; this will eliminate any soft errors that have cropped up. A nice insurance policy to have around.... Pete -- OOO __| ___ Peter Holzmann, Octopus Enterprises OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete ___| \_____ Phone: 408/996-7746
berger@clio.las.uiuc.edu (05/16/88)
I've had a lot of success running RLL encoding on conventional disks.
However, you have two Seagate disks. Seagate is the only company I've
dealt with that explicitely voids their warranty if you use RLL with
any of their standard disk drives. Maxtor, CDC, NEC, Fujitsu, and
others have been very helpful. Seagate was very hard to deal with -
no technical information, just threats.
Mike Berger
Department of Statistics
Science, Technology, and Society
University of Illinois
berger@clio.las.uiuc.edu
{ihnp4 | convex | pur-ee}!uiucuxc!clio!berger