Yay, now I need some Osborne boot media!

Sun Nov 23 22:00:16 CST 2014

On 11/23/2014 06:53 PM, Fred Cisin wrote:
> On Sun, 23 Nov 2014, Jules Richardson wrote:
>> Some PCs will write SD, of course, although I think far fewer will write SD
>> and 128 byte sectors.
>
> The good news is that the Osborne single density was 256 bytes per sector.
> 10 sectors per track, single sided, 40 tracks

It's 128-byte MFM (not FM) that's the problem with a huge swath of PC 
controllers.  And, wouldn't you know it, there were a few systems using 
just that.

The National Semi DP8473 is one of the controllers that can pull that 
one off.  Apparently they reverse-engineered the NEC 765 and didn't 
reproduce the bug.  Shame on them!  Didn't they understand 
"compatibility"?  And yes, the same NS controller handles FM flawlessly.

--Chuck