5-1/4 diskette drive on current computers

Chuck Guzis cclist at sydex.com
Tue Oct 23 19:50:11 CDT 2007

On 23 Oct 2007 at 14:03, M H Stein wrote:

> Nevertheless, in light of the amount of misinformation about the
> subject (apparently even on the MS site) it might be worth mentioning 
> again that at least XP does not have any problems with any of the standard 
> floppy formats (although all except 3.5HD require formatting from a CLI), 
> and that the restrictions, if any, are in the modern BIOSs and mobo 
> hardware no matter how modern (or not) the OS may be.

Anent XP and 2K, one thing that's absolutely required to get anywhere 
is a Windows-conforming boot sector on a disk to be read, complete 
with media descriptor.  The NT/XP/2K/Vista floppy driver reads that 
sector on any newly-inserted floppy then matches it against a table 
of media descriptors it knows about.  No match means you get a 
"General Failure" or some such error, no matter how readable the 
diskette might be in non Windows terms.  This should (but I haven't 
checked) eliminate PC-DOS 1.1 diskettes.

Interestingly, it's possible to *write* a non-Windows conforming boot 
sector on 2K/XP.  When the diskette just written is reinserted, 
however, you won't be able to read it.

This situation obtains even if you use 16-bit VMM access using port 
I/O or BIOS calls. 


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