>Although I know of someone who tried
>and partially succeeded to make a *network* using two specially programmed
>FDCs and some hardware glue. The network was peer to peer MFM (which has
>the property of passing through RF transmitters and other media). This was
>a hack and did not take off either. imho 4MBps MFM for the price of a
>little hardware glue using a plain PC architecture is not a bad deal. Some

The problem with using MFM to do this is that you cannot distinguish between
continuous 0's and continuous 1's. It is alright for a floppy controller as it
makes an assumption at the beginning of a sector that the data sync is all 0's,
and locks on appropriately.

I built a modem using an EPROM and latch chip using M2FM (M squared FM) as
originally proposed by Shugart for double density floppies. This scheme did not
take off as it is slightly more complicated, but it can distinguish between
continuous 0's and continuous 1's for syncing purposes. See a manual for the
Shugart SA800 series disk drives if you need further info. If really needed I
can still dig out the "definition" of the data stream.