Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!hpccc!samc From: samc@hpccc.HP.COM (Samuel Chau) Newsgroups: comp.periphs Subject: Re: ESDI HARD DRIVE Message-ID: <5740002@hpccc.HP.COM> Date: 29 Mar 89 05:45:06 GMT References: <501@ultb.UUCP> Organization: HP Corporate Computing Center Lines: 55 > I am trying to get a 70 megabyte ESDI hard drive to work with an IBM AT > clone (Reliant 286 system to be exact). It has Phoenix Bios 3.10 installed > in it. From what little I found out about the hard drive, it seems to be a > drive of type: 67. The ROM BIOS SETUP goes to type 47. Is there a way around > it? If you can look at the drive and tell me the name of the manufacturer I may be able to help. I have just downloaded a master drive list from Western Digital's support BBS that lists many ESDI drives from various manufacturers. And, like you said, most BIOS ROM hard drive tables stop at type 47, so type 67 doesn't sound right. > I want to put XENIX on it which doesn't use the bios anyway. If I just had > a way of knowing where the registers are and how many cylinders, sectors > per track, landing zone, Ecc, write precomp, and a couple of other > parameters and I think Xenix wouldtake off and do its thing but I don't > know what the parameters are and no one seems to know. Of course IBM > is of no help as usual and the Santa Cruz Operation won't help either. > I have a Western Digital ESDI controller which operates the 1.2meg > floppy just fine... It is possible for an ESDI controller to query the drive for its physical parameters. Of course, it will take some clever programming (probably in assembly language) to get it to work. I assume your ESDI controller is a WD-1007A-WA2? If so, then whether you can configure the drive properly hinges on whether there is a BIOS ROM chip on the controller. WD's BIOS includes a drive parameter table covering several "popular" ESDI drives, as well as low-level formatting and defect sparing routines. The standard DEBUG g=c800:5 enters the utility and should start you off. After the low-level format, DOS 3.3 FDISK and FORMAT can be used to create the appropriate partitions. If your ESDI controller has no BIOS ROM, then according to WD documentation, the motherboard BIOS drive table must provide an entry with the EXACT physical parameters of the drive. #cylinders, #heads and #sectors/track (SPT) are the three most important parameters. Unfortunately most BIOS ROMs include only entries conforming to ST-506 MFM drives, namely with 17 SPT. ESDI drives need 34 SPT. Thus, if you have the facilities to alter the BIOS ROM contents, you can hack in a correct entry for your drive, possibly over an existing drive type that you'll never use. This is exactly what I did for my 386 system to get my new ESDI drive to work just a few weeks ago. Of course, ROM hacking can be very messy, but short of that, you will have to order the WD-1007-WA2 BIOS chip from WD, or hope that the next revision of your motherboard BIOS will provide ESDI drive support! Western Digital's support BBS number is: (714) 756-8176 1200/2400 baud N81 Send me e-mail if you want more information regarding BIOS alterations. Sam Chau HP Cupertino samc@hpda (408) 447-0238 Disclaimer: The opinions expressed above are not those of Hewlett Packard, but only from my humble self.