sparks@batcomputer.tn.cornell.edu (Steve Gaarder) (03/02/88)
We have an old AT (model 99) which we use as a file server with Novell
Advanced Netware 286. We recently purchased a Miniscribe 40 Meg drive
for it. This drive is, I believe, a type 36. Now we have a problem.
Our machine only supports 4-bit drive types. This, I understand, can
be fixed by upgrading the bios. Ok, so I called the IBM flunky here.
He told me that the upgrade was available ONLY with the purchase of a
massively overpriced IBM hard drive. (expletives deleted)
So, folks, the question is: what can I do to upgrade my bios? Is there
a way to get the IBM ROMs? Can a buy a Phoenix or other bios that will
work in my AT? Is there a clever hack I can use?
--
Steve Gaarder
Cornell University, 171 Hollister, Ithaca NY 14853 607-255-5389
UUCP: {cmcl2,shasta,rochester,uw-beaver}!cornell!batcomputer!sparks
BITNET: sparks@crnlthry.BITNET ARPA: sparks@tcgould.tn.cornell.edugerard@tscs.UUCP (Stephen M. Gerard) (03/09/88)
In article <3903@batcomputer.tn.cornell.edu> sparks@tcgould.tn.cornell.edu (Steve Gaarder) writes: >We have an old AT (model 99) which we use as a file server with Novell >Advanced Netware 286. We recently purchased a Miniscribe 40 Meg drive >for it. This drive is, I believe, a type 36. Now we have a problem. >Our machine only supports 4-bit drive types. This, I understand, can >be fixed by upgrading the bios. >So, folks, the question is: what can I do to upgrade my bios? Is there >a way to get the IBM ROMs? Can a buy a Phoenix or other bios that will >work in my AT? Is there a clever hack I can use? You can solve this problem if you have access to an EPROM programmer and two 27256 EPROMs. Basically, you have to pick out a drive table entry that you are not likely to need, and set the values for that entry to values that match your drive. The drive table is composed of sixteen 16 byte entries that specify the number of heads, cylinders, Write Precompensation Cylinder, the landing zone, etc. This table begins at location 0xE401 in the IBM AT BIOS (the BIOS resides in memory at segment offset 0xF000). After changing the drive table, you will have to adjust the checksum byte or else your machine will not be happy with you. :-) If you have access to an EPROM programmer and wish to tackle the project, write me via e-mail and I will tell you the specifics. ------------------------------------------------------------------------------ Stephen Gerard - Total Support Computer Systems - Tampa - (813) 876-5990 UUCP: ...{codas, gatech}!usfvax2!tscs!gerard US-MAIL: Post Office Box 15395 - Tampa, Florida 33684-5395
gerard@tscs.UUCP (Stephen M. Gerard) (03/10/88)
In article <3903@batcomputer.tn.cornell.edu> sparks@tcgould.tn.cornell.edu (Steve Gaarder) writes: >We have an old AT (model 99) which we use as a file server with Novell >Advanced Netware 286. We recently purchased a Miniscribe 40 Meg drive >for it. This drive is, I believe, a type 36. Now we have a problem. >Our machine only supports 4-bit drive types. This, I understand, can >be fixed by upgrading the bios. >So, folks, the question is: what can I do to upgrade my bios? Is there >a way to get the IBM ROMs? Can a buy a Phoenix or other bios that will >work in my AT? Is there a clever hack I can use? If this article appears twice, sorry. Our neighboring site had some news hungar pains, and appears to have eaten this article. You can solve this problem if you have access to an EPROM programmer and two 27256 EPROMs. Basically, you have to pick out a drive table entry that you are not likely to need, and set the values for that entry to values that match your drive. The drive table is composed of sixteen 16 byte entries that specify the number of heads, cylinders, Write Precompensation Cylinder, the landing zone, etc. This table begins at location 0xE401 in the IBM AT BIOS (the BIOS resides in memory at segment offset 0xF000). After changing the drive table, you will have to adjust the checksum byte or else your machine will not be happy with you. :-) If you have access to an EPROM programmer and wish to tackle the project, write me via e-mail and I will tell you the specifics. ------------------------------------------------------------------------------ Stephen Gerard - Total Support Computer Systems - Tampa - (813) 876-5990 UUCP: ...{codas, gatech}!usfvax2!tscs!gerard US-MAIL: Post Office Box 15395 - Tampa, Florida 33684-5395
brad@looking.UUCP (Brad Templeton) (03/13/88)
I just did some work on that 40 meg miniscribe on my old AT. The only thing you need that's tough is to get a low level format done on the whole drive. You need a low level format program (like SpeedStore and others) that can format a drive that isn't in the list of official ones. The dealer who sold you the drive should format it for you. It's the simplest way. Anyway, with this done, the neat thing is that, once under Dos 3.3, fdisk is the only program that looks at the cylinder number. So, use this little TSR provided below to temporarily change the drive descriptor to the 808 cylinders of the miniscribe (I hear some can do as many as 840, mind you) and then use fdisk (dos 3.3) to create an extra dos partition beyond the 32 megs. After that, the drive will still work, even set as a 32 meg drive type code "3". Here's the TSR. It's really boring, and you don't need it all the time. PROGRAM SEGMENT PARA PUBLIC 'CODE' ASSUME cs:PROGRAM TBSR PROC ; set up our table mov al,41h ; int number for disk table mov ah,37 ; dos function to set vector push cs pop ds ; put code segment into ds mov dx,offset drive + 100h int 21h ; now terminate, but stay resident mov dx,(lastloc-TBSR+15+256) / 16 mov ah,49 ; TSR mov al,0 int 21h ; terminate program drive dw 808 ; number of cylinders db 6 ; heads dw 0 dw 300 ; write pre-comp db 0 db 0 ; control byte db 0,0,0 ; dunno dw 808 ; landing zone db 17 ; sectors db 0 lastloc LABEL NEAR TBSR ENDP PROGRAM ENDS END -- Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473
berger@clio.las.uiuc.edu (03/15/88)
I wouldn't rely on the dealer. Even if he formats it for you, there's
no guarantee his disk controller will be compatible with yours, that
he'll use a suitable interleave factor, or that he'll enter the list
of bad sectors. Doing it yourself is the safest way.
Mike Berger
Department of Statistics
Science, Technology, and Society
University of Illinois
berger@clio.las.uiuc.edu
{ihnp4 | convex | pur-ee}!uiucuxc!clio!berger