Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!srhqla!demott!kdq
From: kdq@demott.COM (Kevin D. Quitt)
Newsgroups: comp.os.msdos.misc
Subject: Re: help: peculiar msdos 3.3 crash
Message-ID: <680@demott.COM>
Date: 5 Oct 90 22:30:55 GMT
References: <1286.270b48d3@iccgcc.decnet.ab.com>
Reply-To: kdq@demott.COM (Kevin D. Quitt)
Organization: DeMott Electronics Co., Van Nuys CA
Lines: 47

In article <1286.270b48d3@iccgcc.decnet.ab.com> browns@iccgcc.decnet.ab.com (Stan Brown, Oak Road Systems) writes:
>In article <5XwDq2w163w@bluemoon.UUCP>, andy (Andy Vaught) writes:
>> It looks like you're going to have to go and do a low-level reformat and 
>> backup.
>
>In an earlier posting, I disagreed.  I still disagree.(*)

    So do I.


>> The following restrictions apply:
>>  1) IBMBIO.COM (IO.SYS) must be the first file in the root directory
>>  2) IBMDOS.COM (MSDOS.SYS) must be the second file
>>  3) The files must be the first files stored on disk, and they must be
>> stored in order in contiguous clusters.
>
>1 and 2 are true for all DOS versions up through 3.3 (which was the
>original poster's question).  3 is >> FALSE << for DOS 3.3.  Sometime

    The first cluster of IO.SYS/IBMBIO.COM *must* be in the first data
cluster (cluster #2).  The bootstrap loader does assume it is the first
files on disk and is contiguous, but after the furst cluster it doesn't
matter.  The first thing the code in that first sector's worth does is
to read in the FAT, and reload IO.SYS.

>There may be another problem that will make you reformat your hard disk,
>but this problem is not it.
>
>(*) If IBMBIO.COM/IBMDOS.COM are scrogged beyond repair, and something
>else is occupying their sectors, then you do have to reformat your hard
>disk.  But it's not a low-level reformat, just a simple "FORMAT C: /S".

    Even still should not require a format.  Judicious use of debug to
move cluster around, and something like NU to make it easier to edit the
contents would allow you to move whatever's in cluster 2 away, then you
can either SYS the disk, or reboot from floppy and COPY io.sys and
msdos.sys onto the hard disk.  (the reboot is necessary so that DOS will
re-use that lowest cluster instead of the lowest "cluster that hasn't
been used yet this session". 

-- 
 _
Kevin D. Quitt         demott!kdq   kdq@demott.com
DeMott Electronics Co. 14707 Keswick St.   Van Nuys, CA 91405-1266
VOICE (818) 988-4975   FAX (818) 997-1190  MODEM (818) 997-4496 PEP last

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