Date   : Thu, 01 Nov 2007 07:16:07 +0000
From   : mike@... (Mike Tomlinson)
Subject: BBC drives

In article <000701c80b45$a9c666a0$0a00a8c0@...>, Mark Usher
<mu.list@...> writes

>Just out of curiosity... And before I get my screwdriver out....
>Has anyone tried using a BBC 5.25" drive connected to a PC to read and write
>BBC discs ?

Yes. I found it worked much more reliably than using a PC 1.2Mb drive.
I think one reason is that a 1.2Mb drive spins high density disks at
360rpm vs. 300rpm for double-density media.

I used the BBC cable (i.e. straight through), not the PC cable with the
twist.

[[[ As an aside, I always thought a 1.2Mb drive slowed its spindle speed
to 300rpm to read/write double-density discs, but was not sure how this
was done (whether the drive senses the disk density and chooses the
appropriate speed, or whether it is done by the disk controller.)

A google suggests that the drive doesn't actually slow down, but
supplies the data to the controller at a higher rate, which may cause
difficulties for older applications like FDC and Anadisk not expecting
this.  See:

  http://www.retrotechnology.com/herbs_stuff/drive.html#300K
  http://www.strafom.force9.co.uk/bbc/Retrobbc/FDC.htm  ]]]

In any case, I had very good results attaching a BBC drive to a PC and
using that to read/write BBC discs.  Another advantage is that you're
writing disks on the same drive, so when it's returned to the BBC, there
are no head alignment issues to worry about.

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