mvolo@ecsvax.uncecs.edu (Michael R. Volow) (08/30/89)
Thanks to all who responded to my query about upgrading a hard disk on the original IBM AT. >In our lab we have one of the early 6 MHz IBM AT's. Although the >20 Meg original HD is still working (yes it was one of those that >was supposed to die - CMI? - I believe). We need more disk space, >somewhere between 40-70 MB. What do we need to do? I've heard that >the ROM's in this machine have only a limited number of disk sizes >and types. Should we spring for a new controller at the same time? >Any recommendations about sturdy HD's in this range suitable for >frequent usage? Any help would be appreciated. > >M Volow, VA Medical Center, Durham, NC 27705 >mvolo@ecsvax.UUCP 919 286 0411 Responses: ************************** I would use the Seagate st296N and sto1B host adapter. It's 1/2 height so you should have room for it and the old drive. You don't need to set it up in Rom, and the host adapter can co-exist with your old drive/ controller. $550 or so for the Kit and you get 80 meg and 28ms access. Bob -- Bob Duckworth Georgia Insitute of Technology, Atlanta Georgia, 30332 uucp: ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!gp310ad ************************** I too have an original AT. I have been quite satisfied with my Seagate 251-1 since my old CMI croaked 2 years ago. It is a relatively fast ~28msec 42meg drive and does not require BIOS or controller changes (comes with OnTrack partitioning software that works just fine). + Ronald S. Woan ron@woan.austin.ibm.com + + outside @cs.utexas.edu:ibmaus!auschs!woan.austin.ibm.com!ron + ************************* I have been using CDC 94155-86 drives in my AT-now-a-386SX machine for quite a while. They are very well built, sturdy drives with auto-parking heads. (AT&T used them in the non-SCSI 3B2 series) Mine are now formatted RLL for 110 MB. MFM yields about 72MB. The -86 model is 925 cylinders, 9 heads. There is a 94155-85 model which is 1024 cylinders, 8 heads. This is a more common drive type for PCs. When I used these in my AT, I used type 12 which had the wrong number of cyls/heads, but used OnTrack Disk Manager to change parameters and format all. Anyway, a source of mine has had these drives on *special*. I could sell you one for about $500. Should work fine with your current controller. Or if you want to format RLL and get 110 MB, the RLL controllers (16 bit) are $125-$150. BTW, the average access on the drives mentioned above is 28 ms. I have seen some 40 MB Atasi drives for around $200 but I think they are slower, ~45ms.? Drop a line if you are interested or need more info. doc@holin.att.com (David Mundhenk) ************************ I was faced with the same problem when the 6MHz AT in my lab sent it's CMI 20 meg to never-never land. I just bought a copy of Speed stor and I've had combinations of 10,20,32,40,70,and 80 Meg disks installed with no problems. I would highly recommend the speed stor program even if you do get a drive that is BIOS supported (which aint many). Mike Davis (davis@louie.udel.edu) (128.175.1.3) ************************ I recommend you purchase a Maxtor drive and an Adaptec 2372B RLL controller. The controller will allow the AT to talk to drives independent of the limited BIOS drive-types table; and the Maxtors are high enough quality to work with RLL regardless of whether or not they're "qualified" as RLL or not. Our standard configuration includes the Adaptec RLL controller and a Maxtor XT-1085. We even push the drive beyond it's specified 1024 cylinders to 1224 (usually) but you may not want to do that. With the 8 heads, 1024 cylinders, 26 sectors/track and 512 bytes/sector you'll get almost 110 Megabytes _formatted_ capacity. If you're looking fo a vendor I can recommend K.I.S. Computer Center 519 Mantague Expwy. Milpitas CA 95035 (408) 942-8088 The controller is about $140; the drive is about $595. From: keithe@tekgvs.labs.tek.com (Keith Ericson) *********************** I would look at getting the fixed disk from CDC (Control Data Corporation). It is from the Imprimis division which (I believe) was recently sold to Seagate. Anyway, we've had good luck with their drives (we OEM their stuff for our products at Tektronix). You might also look at some of the newer controllers. The old IBM BIOS only supported a few (14) drive types; many which are very unusual drives. The old IBM systems are their model 99; they also made a model 299 which ran at 6 MHz but had a newer BIOS that supported more drives. Anyway, here we've used the Adaptec 2372 RLL controller with good success. Western Digital was also supposed to release a new RLL controller which was stated to be better. I don't have any experience here, though. For drives, you'd probably be interested in: 1. CDC Wren II Half height (which is 40 MEGs standard; 60 MEGs RLL). 2. CDC Swift 3 1/2" (which is 80 MEG standard; 120 MEGs RLL). For the Swift you'll need a 3 1/2" to 5 1/4" adapter. Adaptec and Western Digital controllers should be available from Wyle Laboratories (who is one of their distributors). CDC is generally available either directly from CDC or through Almac Electronics; we buy direct. jamesa@amadeus.LA.TEK.COM *********************** In my PC AT I have a Maxtor XT-1140 harddrive. This beast cranks out 112 Meg worth of disk space. Using DOS3.3 this gives you roughly 3.5 30Meg drives installed. I use it as my main drive. With the size of the regular 20Meg AT drive, it fits perfectly. Call or Write: Maxtor Corp. 211 River Oaks Parkway San Jose, CA. 95134 (408) 432-1700 They should be able to help you out. Also, you might look into some of the larger Seagate drives. George W. Pogue, 1300 Two Tandy, Fort Worth, TXtexbell!letni!rwsys!trsvax!slimer *********************** I've just replaced my old CMI disk in an original-issue AT with a really nice Toshiba 66 MB RLL disk. You can also use it as a 44 MB MFM, but it's definitely worth springing the $150 (or less, perhaps) for a new controller board. I have a Western Digital. A little tricky to install, but it works fine. One thing to watch out for, however. I thought it was the CMI that failed -- and it may very well have. But the power-down problem I was hearing on the CMI reappeared (once only, so far) with the Toshiba about a week after I installed it. I would definitely look into replacing the power supply as well. It was underpowered to begin with and after four or five years the Wheatstone bridge components probably start to degrade due to heat and use. From: slimer@trsvax.UUCP ********************** >For an old IBM AT, I am trying to locate the table which contains >the dimensions (e.g. meg, cylinders, heads, etc.) of the 15 or >so drives compatible with the original ROMs. The place you want to look is the IBM Technical Reference manual for the AT. In case you don't have one (IBM no longer publishes it since the AT is defunct) I've included the following summary from page 1-63: Type Cylinder Heads Write Precomp Landing Zone 1 306 4 128 305 2 615 4 300 615 3 615 6 300 615 4 940 8 512 940 5 940 6 512 940 6 615 4 none 615 7 462 8 256 511 8 733 5 none 733 9 900 15 none 901 10 820 3 none 820 11 855 5 none 855 12 855 7 none 855 13 306 8 128 319 14 733 7 none 733 15 Extended Parameters (hex 19 and 1A) The next table refers to the extended parameter table which is used if you have the newer IBM BIOS Type Cylinder Heads Write Precomp Landing Zone 16 612 4 All Cyl 663 17 977 5 300 977 18 977 7 none 977 19 1024 7 512 1023 20 733 5 300 732 21 733 7 300 732 22 733 7 300 733 23-255 RESERVED Hope this helps. James E. Akiyama jamesa@amadeus.LA.TEK.COM M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411
mr@cica.cica.indiana.edu (Michael Regoli) (08/31/89)
mvolo@ecsvax.uncecs.edu (Michael R. Volow) writes: >Thanks to all who responded to my query about upgrading a hard disk >on the original IBM AT. (damn! i'm sorry i missed this. --mr) here was one recommended solution: >>I too have an original AT. I have been quite satisfied with my >>Seagate 251-1 since my old CMI croaked 2 years ago. It is a >>relatively fast ~28msec 42meg drive and does not require BIOS or >>controller changes (comes with OnTrack partitioning software >>that works just fine). >>+ Ronald S. Woan ron@woan.austin.ibm.com + >>+ outside @cs.utexas.edu:ibmaus!auschs!woan.austin.ibm.com!ron + yes, that's what we did too, to our original IBM-AT when our CMI began developing alzheimer's... the 251-1 is a swift drive for this "voyager (tm)" of a PC in today's world... however, OnTrack formats this drive into two, and, as far as my experiments go, CANNOT accept DOS 4.01 since the old BIOS table doesn't support drives whose IDs are >15. there *has* to be a better way around this. of course Big Blue has abandoned support for this machine and replacement updated ROMs are scarce as "hen's teeth." has anyone experimented with a phoenix or award BIOS to put into this machine to extend its drive table? i've got DOS 4.01 ready and waiting to use that 42Mb as one drive... (as a side note, our CMI 20Mb disk *just* departed: it served us amicably for almost FIVE YEARS. this from a drive (according to PC MAGAZINE) wouldn't last one year. [remember the pictures of the guys in florida dumping the drives into the ocean?!]) -- michael regoli mr@cica.indiana.edu regoli@iubacs.bitnet ...rutgers!iuvax!cica!mr