Re: //c 5 1/4 to PowerMac

[nathan@visi.com (Nathan Mates)]

In article <4039180286.20312924@lamg.com>,
Robert Roehm <Robert_Roehm@lamg.com> wrote:
>"Dumb" means it does not have any data on how the floppies are written and
>read... that information has to be sent from the disk utility on the HD or
>controller card. 

   Problem: most of the drives are already pretty dumb as per your
definition; it's the stumbling block of the controller card requiring
data in a particular format (MFM on IBM PCs, GCR on Apple IIs). The
drive takes signals as to head positioning, motor stop/start, write
protect, and a signal representing the bit encoding (read/write).
However, the controller card is responsible for turning this signal
into a bitstream for the host computer, and PC and Apple IIs have
rather different formats.

   With a new controller card, the 'dumb' drives can read the wrong
system's disk. The only other alternative is the real 'smart' drives
that can munge data into the form the controller card expects or some
other method. Apparently the Commie 64 drives (they had their own 6502
controlling them, so I guess they definitely are not dumb) can read
GCR and MFM disks because the controller could be reprogrammed for a
new format. Can't do that to the hardwired logic of PC and Apple II
controllers.

Nathan Mates

--
<*> Nathan Mates http://www.visi.com/~nathan/      <*>
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# think-- what are the facts, and to how many decimal places?  -R.A. Heinlein