WTD: 5.25' DSDD drive & Acorn Master128 keystrip scan/schematic

[Tony Duell]

> It was common practice to use 96 tpi drives for both 40 and 80 track
> disks on BBC micro systems. If someone only had a 48 tpi drive and
> couldn't read the disk written on the 96 tpi drive the usual solution
> was to format it on the 48 tpi drive and then re-write it on the 96
> tpi drive.


What good does that do? The 40 cylidner drive will write a wide track 
when formatting, the 80 cylinder drive will re-write the middle of it 
with data when you write to the disk, the 40 cylinder drive will then get 
a mix of the data and the formatting pattern. That's the sort of thing 
that _causes_ the problems

You'd be better off bulk-erasing the disk (with an AC-enegized 
electromagnet, not a disk drive!), formatting it on the 80 cylinder 
drive, writing it there, and the reading it on the 40 cylinder one.

-tony