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- Path: 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
- Sender: news@zl2tnm.gen.nz (GNEWS Version 2.0 news poster.)
- References: <JAN.92Dec22183354@pallas.neuroinformatik.ruhr-uni-bochum.de>
- Distribution: world
- Organization: The Wolery
- Lines: 16
-
- 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
-