Article View: comp.sys.amiga.tech
Article #2496Re: DMA in VM
From: Valentin Pepelea
Date: Sun, 03 Dec 1989 08:14
Date: Sun, 03 Dec 1989 08:14
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In article <14068@grebyn.com> ckp@grebyn.UUCP (Checkpoint Technologies) writes:
>
>It happens that the 68851 PMMU, as used in the A2620 card, has just that
>feature: a separate page table for a DMA device. It may be remotely
>possible to press this into service in the Amiga, but I doubt it.
The 68851 MMU resides between the main processor and memory. If a DMA device
wanted to access the memory through the MMU, it would have to be sitting on the
same side as the processor. Obviously impossible.
>However, the 68030's built-in PMMU doesn't have this feature, ...
For obvious reasons.
Valentin
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!cbmvax!valentin From: valentin@cbmvax.UUCP (Valentin Pepelea) Newsgroups: comp.sys.amiga.tech Subject: Re: DMA in VM Message-ID: <8800@cbmvax.UUCP> Date: 3 Dec 89 08:14:35 GMT References: <14059@grebyn.com> <838@tardis.Tymnet.COM> <14068@grebyn.com> Reply-To: valentin@cbmvax.UUCP (Valentin Pepelea) Organization: Commodore Technology, West Chester, PA Lines: 20