RX01 Floppies

Johnny Billquist bqt at update.uu.se
Fri Nov 21 18:28:56 CST 2014

On 2014-11-21 12:44, tony duell wrote:
>>> Is it correct that RX01 format floppies can be created from blank
>>> floppies with a standard PC floppy controller (or at least some
>>> controllers / motherboards, depending on the controller chip) while
>>> RX02 format floppies cannot?
>> Yup.  The RX02 ("double density") use a whacky MFM scheme (with some
>> code substitutions) for data with FM sector headers.  Not doable at all
>> with a standard PC setup.  RX01s are pretty much stock FM.
> I seem to remember that if you format an 8" floppy, single sided, single density
> 'IBM3740 format' (the standard one, 77 tracks, 26 sectors/track, 128 bytes/sector)
> then at least an RX02, and probably an RX01 can be convinced to put the DEC
> type directory, etc. on it. An RX02 can re-format it as MMFM too.

Of course. You don't even need to do any convincing. A directory (which 
differs between different OSes) can always be written. That is just 
bytes of data on the floppy.

> Most CP/M machines with 8" drives can do the intial format

I should probably point out that an RX01 or RX02 cannot actually format 
floppies at all. They need preformatted floppies, in the IBM format.


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