Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!psuvax1!psuvm!jxs118
From: JXS118@psuvm.psu.edu (Jeff Siegel)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: When can you SYS a disk not originally formatted with /S?
Message-ID: <91123.230837JXS118@psuvm.psu.edu>
Date: 4 May 91 03:08:37 GMT
References: <1991May3.191723.24131@midway.uchicago.edu>
 <Ec8V7vK00awO06V0ZW@andrew.cmu.edu>
Organization: Alphabetical
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A (hopefully) complete answer on when you can sys a disk. For a disk to
be bootable, the following conditions must be true:

1) The disk has a valid bootstrap sector. This is true of practically every
disk formatted with the DOS FORMAT command. If you used some other formatting
process, it may not be the case.

2) The first two directory entries on the disk are IBMBIO.COM and IBMDOS.COM,
in that order.

3) The file IBMBIO.COM is the first file to occupy the data space. The
clusters of the file must be in order and must be contiguous.

4) The file IBMDOS.COM is on the disk somewhere. Can be anywhere, and doesn't
have to be contigiuous.

Thus a disk is 'sys'able if the first two directory slots are empty and if
there is room to put IBMBIO.COM down as the first file in the data space.
However, I would bet the DOS sys command is stupid and therefore applies
more restrictions than are actually necessary.

Jeff