ST-506 hard drive emulation

[Pete Turnbull]

On Jul 26 2005, 14:42, Jules Richardson wrote:

> I'm not sure how complex such a box would be. I *think* an ST506-
> interface drive looks pretty much like a big floppy, just with more
> heads. Far as I know, it doesn't do anything intelligent on the drive
> itself, just responds to head select / step commands from the
controller
> and reads or writes data.

Yes, except normally the step pulses are buffered, so you can send them
fast and the drive will handle them at the correct rate.  At least, all
but the oldest drives do that.  That's the main difference between
ST506 (not buffered) and ST412 interfaces.

> The bit I don't know is the nature of the data signal at the
interface -
> it uses +/- signal lines for both read and write data. I'm not sure
if
> that's an analogue signal or a digital one.

Digital.

> I don't think there's a need to handle anything complex in the
virtual
> drive. I believe an ST506 drive's purely a data store/replay device
and
> it knows nothing of the actual data stored on it - most of the
circuirty
> on board is presumably just motor control and head amplifiers /
filters.

Correct.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York