Re: PLIP: Parallel Line IP.

["C.P.Briscoe-Smith" <cpb4@ukc.ac.uk>]

>Check out this link to find out about PLIP, a networking
>protocal that uses the Parallel port.  Would be useful
>to Falcon users for High speed links with MiNT, Linux,
>or some other Unix type OS.  It would help in the transfer
>of data between PC, Amigas and Falcons.

>http://www.medunsa.ac.za/linux/nag/38.htm

Thanks for all the interesting links you've been suggesting.  Many have
been ending up in my bookmarks list!

MiNT already has a PLIP driver, believe it or not.  I can FTP between
two standard STs at about 15Kb per second across it.  Unfortunately,
it's not the same PLIP as Linux uses.

Linux PLIP outputs 4 bits of data and a strobe through D0, D1, D2, D3
and D4, and inputs them through ERROR, SLCT, PAPOUT, ACK and BUSY.
This gives a 4-bit full duplex path.  The Atari parallel port doesn't
have ERROR, SLCT, PAPOUT or ACK, though.  Atari PLIP uses D0-D7 to
carry data, and STROBE->BUSY to strobe.  If both ends send data at
once, both will be driving the same lines at once, which seems not to
harm the Atari's parallel port drivers (anyone know more about this?).
I'd be reluctant to try the same thing with a PC, though; I've no idea
how well the line drivers would cope with this.

Oh, I've just seen (I'm looking at drivers/net/README1.PLIP in the
Linux v1.2.13 sources) that Linux has an 8-bit PLIP mode, too.  This
also seems to use many more lines than the ST has access to (INT, ACK,
AUTOFD, PAPOUT, SLCT, SLCTIN) and it warns not to use it "on
unidirectional ``printer'' (as opposed to ``parallel'') ports or when
the machine isn't configured for PLIP, as it will result in output
driver conflicts and the (unlikely) possibility of damage."

So, do we change MiNT to work with Linux, or change Linux to work with
MiNT?

--Charles