Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!ugle.unit.no!ugle.runit.sintef.no!thoger From: thoger@solan.unit.no (Terje Th|gersen) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: How to partition a drive on AT without drive table entry? Message-ID: Date: 19 Mar 91 06:25:35 GMT References: <5831@trantor.harris-atd.com> <1991Mar15.134518.10866@bwdls61.bnr.ca> <5854@trantor.harris-atd.com> Sender: news@ugle.unit.no Organization: Institute of Physical Chemistry, NTH Lines: 58 In-Reply-To: sonny@charybdis.harris-atd.com's message of 18 Mar 91 20:39:54 GMT In article <5854@trantor.harris-atd.com> sonny@charybdis.harris-atd.com (Bob Davis) writes: In article <1991Mar15.134518.10866@bwdls61.bnr.ca> coop4y44@bwdla28.bnr.ca (Takis Skagos) writes: >In article <5831@trantor.harris-atd.com>, sonny@charybdis.harris-atd.com (Bob Davis) writes: >> >> I have an AT clone for which I am trying to partition >> an MFM drive using DOS's FDISK command. Apparently FDISK only >> knows to assume Cylinders and Heads for the drive as those selected >> during Setup of CMOS RAM. But there is no match of Cyls/Hds available >> during Setup on my machine to match my hard drive. >> Is there some way that I can partition this MFM drive without having >> the right drive type in BIOS? Is there software available to do whatever >> my Adaptec controller BIOS did before? > > On my machine there is a blank entry in my drive table that >can be set up by the user. You might want to check that out. > > Taki Thanks for the reply. This weekend, I heard the rumor that both AMI and Award BIOSes have such a wild card Drive Type entry. Can someone enlighten me on how to access and use these to specify any desired number of Cylinders and Heads for a non-standard disk drive? AMI BIOS' will tell you 'strike DEL to enter Setup / Diagnostics' on bootup. On Award types you strike Ctrl-Alt-Esc on bootup. Re doing this in software, here's a *really* quick and dirty way of doing it : You know all those interrups? They all have a 4-byte entry down in low dos memory. When the machine executes an interrupt, these entries are used as a jump table. Now, a lot of interrupts are never used, (the BASIC-vectors on a non-IBM machine come to mind), which leaves us with a little bit of "free" memory down there. On my old Sperry/IT semi-AT compatible, i wrote a small (10 turbo-pascal lines) program which put the drive-table entry for my harddisk into this area, and set Int 41h vector (which is the vector that's assigned to point to the drive table for HD 1) to point to the table. I probably left lot of people shocked out there now, but this worked like a charm for close to two years. The advantage of doing it like this is that you don't need a RAM-hogging TSR or need to figure out how to write a device-driver. Of course, you'd better be sure that those interrupts you are zapping really aren't used. I'm afraid I don't remember which ints I decided were safe. The machine still ran Windows 3.0, WP, TP 5.5, TC 2.0, TCPP 1.0, + a lot of games etc, etc, with the table installed. Send me a note, if you want the code. (If you send me your drive-parameters, I might even modify it for you..) Regards, -Terje -- ____________________________________________________________________________ thoger@solan.unit.no | Institute of Physical Chemistry THOGER AT NORUNIT.BITNET | Div. of Computer Assisted Instrumental Analysis | Norwegian Institute of Technology