Subject: Re: Some Questions
To: None <port-sun3@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: port-sun3
Date: 08/11/1995 10:43:49
>> #1: Is DMA working now (Ethernet and/or SCSI)?
>>     The last time, i ran NetBSD, its performance was worse than
>>     bad, because it did no DMA at all!

> I fail to see how Ethernet could work at all without DMA.  Ethernet
> requires that you be able to take input at 1.25 MB/s immediately upon
> start of packet.  On the Sun3, this is done via DMA into a buffer.

Not that I wish to suggest it is relevant to the Sun-3, but there is
nothing about Ethernet that demands DMA.  For example, I could easily
imagine a card that delivered packet data by reading some register
repeatedly.  (No, it's not something I'd want to use for routine use.
But it might be useful for boot ROMs that want to be small and simple.)

					der Mouse