Return to BSD News archive
Newsgroups: comp.unix.bsd Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!darwin.sura.net!jvnc.net!nuscc!ntuix!eoahmad From: eoahmad@ntuix.ntu.ac.sg (Othman Ahmad) Subject: Re: DOS and 386BSD (and NT and OS2) Message-ID: <1992Oct15.081904.20697@ntuix.ntu.ac.sg> Organization: Nanyang Technological University - Singapore X-Newsreader: TIN [version 1.1 PL6] References: <1992Oct15.025722.15943@fcom.cc.utah.edu> Date: Thu, 15 Oct 1992 08:19:04 GMT Lines: 45 A Wizard of Earth C (terry@cs.weber.edu) wrote: : |> : |> I am somewhat confused now. Should the DOS primary partition be put first : |> (avoiding the problem that you can't run past cyl. 1023) or second, to : |> keep asboot, disklabel, family happy? : : I believe that the confusion here lies with the fact that Othman's procedure : will not work on a geometry translated drive. : I may be wrong but I recall being told that the translation is not done by bios, rather by the controller. The real geometry of the IDE disk is that of variable number of sectors for each cyclinder, to get the maximum number of bytes. I do not think that there is any OS that can handle varaible sector number so the disk controller must convert the variable sector number to a linear number. The input parameters are the number of sectors per head, and number of heads per cylinder. Theoretically, we can just choose any geometry on the bios, and it will work. Provided your bios/software know the geometry that you store your data in. I did this on a Western Digital 40Mbyte hard disk. However the IDE controller may allow software to read a recommended geometry, which may be different from the BIOS setting(in CMOS RAM). DOS still works because of the above reason. The problems come because of the mismatch between BIOS and disklabel geometries. However DOS and 386bsd can still co-exist in this circumstances. Just instruct the OS boot manager to load the appropriate partitions calculated using the BIOS informations, converted from the disklabel info. I have worked with 200Mbyte Conner, 200Mbyte Maxtor, 120 Mbyte Maxtor. I have another 240mbyte quantum pro IDE, but I believe I can install the DOS as well, but I must have the OS-BS software. Otherwise, it will surely fail. -- Othman bin Ahmad, School of EEE, Nanyang Technological University, Singapore 2263. Internet Email: eoahmad@ntuix.ntu.ac.sg Bitnet Email: eoahmad@ntuvax.bitnet