Re: question about DMA devices

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Article #10837

#10837

From: Don Stokes
Date: Thu, 24 Dec 1992 01:37

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jan@pallas.neuroinformatik.ruhr-uni-bochum.de (Jan Vorbrueggen) writes:
> A number of smaller Vaxen (only the uVaxI? or also the 725/730?) didn't have
> these and in general had to do I/O a page at a time...probably still slightly
> faster than a PC/XT :).

The MicroVAX I addressed memory on the Qbus, in the same way it addressed
peripherals.  DMA is no different on these systems, except that there is no
need for mapping registers because the memory is in the same address space
as the peripheral and can be addressed directly.  I'm not sure about the 
11/730, but there's nothing special about the I/O adapters -- bog standard
Unibus devices that presumably have some sort of map into memory.

--
Don Stokes, ZL2TNM (DS555)                        don@zl2tnm.gen.nz (home)
Network Manager, Computing Services Centre            don@vuw.ac.nz (work)
Victoria University of Wellington, New Zealand              +64-4-495-5052

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Path: arc1-ca.pugleaf.net!sparky!uunet!comp.vuw.ac.nz!zl2tnm!toyunix!don
Newsgroups: comp.arch
Subject: Re: question about DMA devices
Message-ID: <17596358@zl2tnm.gen.nz>
From: don@zl2tnm.gen.nz (Don Stokes)
Date: 24 Dec 92 01:37:25 GMT
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