Compaq Portable II - Restoration Problem, Help requested

Chuck Guzis cclist at
Sat Jan 2 17:48:12 CST 2010

On 2 Jan 2010 at 14:24, Fred Cisin wrote:

> Instead of messing with my boot sector, howzbout creating a bogus
> directory entry, as is done for disk name, or long filenames, at the
> physical end of the directory sectors.

This is particularly ironic since Microsoft had complete control over 
what constituted an MS-DOS floppy boot sector since the beginning.  
Indeed, they even changed it a couple of times.

The annoying thing about the boot sector rewrite is that it happens 
if the floppy is writable (i.e. write-protect is off); it doesn't 
matter if a file was opened on the floppy for writing or not.

I'm too lazy to verify this, but I believe that most standard DOS 
floppy formats do not fully occupy the last sector of the FAT with 
allocation information.  So writing the volume tracking data (if you 
had to do it) at the end of the last FAT sector in the second FAT 
copy would likely do the least damage.

In any case, why track volume information if (a) the floppy doesn't 
have files open for writing and (b) one can handle write-protected 
floppies anyway?

But then, Microsoft has the top technical talent, don't they?


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