Other disk and drive types (Was: Hard-sector discs -- how many

Philip Pemberton classiccmp at philpem.me.uk
Fri Nov 20 17:22:54 CST 2009

Fred Cisin wrote:
> Will your circuitry be able to handle the doubled data transfer rate?

The acquisition clock rate is 40MHz. That means every clock tick in the 
acquired timing data represents 25 nanoseconds. My current torture-test 
is to feed it a 10MHz "read data" signal, which it's handling fine. It's 
actually having more trouble with the slower bit rates because there are 
one or two little issues with the pseudo-RLE compression.

I seem to recall mentioning that it'll read MFM hard drives, which 
typically have a 5Mbps data rate. 1Mbps should not be an issue. You'll 
have more trouble soldering the adapter cable together than you will 
getting a valid data readback!

> I think that the first 34 pins are the same.  I only have a few of those
> drives, and they are many archeological layers deep.   The pinout of the
> ones that IBM used on the PS/2s (with the 6 extra pins for power) might be
> in the AT "Options and Adapters" Tech Ref

Knowing IBM, I wouldn't be surprised. I think my 2.88 drive is buried in 
a box somewhere (it was "liberated" from a dead PS/2 of some 
description) but I don't have any discs for it.

classiccmp at philpem.me.uk

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