Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!uunet!hitachi!jon
From: jon@hitachi.uucp (Jon Ryshpan)
Newsgroups: comp.arch
Subject: Re: Fast Data transfer between ATs
Message-ID: <452@hitachi.uucp>
Date: 12 Jun 90 01:11:39 GMT
References: <1990May25.230643.11857@monu6.cc.monash.oz>
Reply-To: jon@hitachi.UUCP (Jon Ryshpan)
Organization: Hitachi America - Semiconductor & IC Div.
Lines: 14

In article <1990May25.230643.11857@monu6.cc.monash.oz> rda903l@monu6.cc.monash.oz (m.c. 8846372 vella) writes:
>...	Is DMA the fastest way to transfer data between my board
>and memory?

I don't think so.  In the AT the data has to go from the peripheral to
the DMA chip and then out of the DMA chip into memory.  Very often the
CPU can do this faster.  This can be the best way if the CPU doesn't
have anything better to do (very common under DOS) or if you really want
the *fastest* data transfer possible.

Some but not all of the implementations of the AT bus support transfer
of bus mastership.  On such a backplane, DMA would be fastest.

Jonathan Ryshpan		<...!uunet!hitachi!jon>