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From: rlw@ttardis.UUCP (Ron Wilson)
Newsgroups: comp.sys.3b1,u3b.tech,comp.sys.att
Subject: Re: SCSI or ethernet via parallel port ?
Message-ID: <2675@ttardis.UUCP>
Date: 2 Feb 91 04:13:19 GMT
Organization: Gallifrey
Lines: 31

In article <38458@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) writes:
>merce@iguana.uucp (Jim Mercer) in <1991Jan25.035120.11117@iguana.uucp> writes:
>
>	there exist on the market a number of "thingy"'s that attach to the
>	parallel port.
>	[...]
>	but there are newer gizmos which can, with drivers under MS-DOS, adapt
>	the port into a SCSI controller or an ethernet NIC.
>	[...]
>	on the unix-pc/CT miniframe, you can write loadable device drivers.
>	could a driver be implemented to use one of these devices?
>
>Nope.  The 3B1/UNIXPC's parallel port is NOT a programmable I/O device with
>data-direction registers; it is a printer port, period.

While I can't speak for these parallel port SCSI and ethernet adaptors, I do
know that PC products like Fast-Lynx (aka Fast-Wire), Brooklin Bridge, Lap
Link and others use the port data pins ONLY as outputs and use the control
signal inputs for data input - thus only transfering 4 data bits at a time
with OUT reconfiguring the parallel port.

In theory, the same trick could be used with the Unix-PC parallel port.

----------------------------------------------------------------------------
About MS-DOS: "... an OS originally designed for a microprocessor that modern
                kitchen appliances would sneer at...."
                   - Dave Trowbridge, _Computer Technology Review_, Aug 90

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