Path: utzoo!utgpu!watmath!clyde!bellcore!rutgers!ucsd!ucbvax!VAX.FTP.COM!jbvb
From: jbvb@VAX.FTP.COM (James Van Bokkelen)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: ethernet card portability
Message-ID: <8812080058.AA05309@vax.ftp.com>
Date: 8 Dec 88 00:58:49 GMT
References: <8812062152.af22648@Obelix.TWG.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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In general, a PC-bus (8-bit slot) card will run in all machines.  A 16-bit
slot card usually requires an AT (but 3Com's 3C505 will go 16-bit on an AT,
but runs in an 8-bit slot on PCs).

There are two classes of potential problems:  Some cards aren't fast enough
to deal with fast (>6Mhz) busses.  Early U-B NIC cards were this way, but
they've fixed it.  Another problem is drivers that contain timing loops on
very fast processors (regardless of bus speed).  There are a few cards out
there (usually with on-board processors) which require waits in the driver
that can't be done with clock interrupts (they take too long and the card
times out).  This problem may be software-vendor-dependent, too.

The 3C503 and the WD8003 should work in all the machines you mention.  One
of the advantages of the MCA bus is that it is supposed to be sufficiently
well specified that the clock rate problems I mention above can't happen,
but you can still get the timing loop problem....

James VanBokkelen
FTP Software Inc.