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Date:	Wed, 22 Oct 2003 20:48:46 PDT7
From:	Steve Carter <scarter@vcnet.com >
Reply-To:	scoug-help@scoug.com
To:	scoug-help@scoug.com
Subject:	SCOUG-Help: sysinstx ?

Content Type: text/plain

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All this DOS stuff makes my head hurt.
------------------------------
Programs compressed with PKLite for DOS can be expanded with:

CAUNLITE.EXE 17,376 1-01-93
DISLITE .DOC 19,337 4-14-92
DISLITE .EXE 17,358 4-14-92

All of which I still have handy (for no reason other
than sloth and cheap, large hard disks). LXLite is OS/2 specific.

I believe that SYS.com merely placed copies of MSDOS.SYS and IO.SYS
(or their equivalents in the IBM/DRDOS world) in the correct locations,
i.e. the _VERY_ first entries in the FAT 16 partition.
The MBR loader was not smart enough to find them otherwise.

Traditionally, the MBR took up just one sector, the very first
one on the disk. The partition table was at the end of that sector,
and defined the four possible partitions. So boot code was limited
to well under 512 bytes. The other sectors in cylinder 0 were vacant.
Partitions start on a cylinder boundary.

This leaves considerable room for both boot sector viruses or
boot managers to locate additional code for a more complicated
procedures. I think PowerQuest's PQBoot is such a product,
as opposed to IBM's Boot Manager which requires a partition.

+++++++++++++++++++
On 10/22/03, Peter Skye wrote, in part:
>>
>> SYS.COM didn't transfer the Master Boot Record (MBR)
>> and you needed to use FORMAT if you wanted an MBR.
>
>I may have blown it on the above. It would make no sense for SYS.COM to
>_not_ write an MBR. I just tried to look inside SYS.COM (MS-DOS 6.22)
>to see if there was any in-line documentation but the top of the program
>says "PKLITE Copr. 1992 PKWARE Inc. All Rights Reserved" and there's not
>much else readable so it might be a compressed executable (LXLITE) or
>something. (And I don't know how to uncompress an LXLITE executable for
>viewing.)
>
>Anyway, SYS.COM might write the MBR in which case SYSINSTX probably also
>writes the MBR. And if that's the case then SYSINSTX might mess up your
>boot loader (any flavor including the one that comes with LVM) or your
>MaxDrive (or whatever Maxtor called it) or anything else that puts
>itself on the very first cylinder of your first disk.
>
>The triumvirate of SYSINSTX, boot loader compatibilities and LVM are
>severely straining my noggin's quest to understand them. Comments more
>intelligent than mine would be GREATLY appreciated. >- Peter

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