Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!apple!jrg
From: jrg@Apple.COM (John R. Galloway)
Newsgroups: comp.arch
Subject: Re: PMAX/DS3100 frame buffers
Message-ID: <27738@apple.Apple.COM>
Date: 23 Mar 89 03:47:12 GMT
References: <93849@sun.Eng.Sun.COM> <5845@mit-vax.LCS.MIT.EDU> <1989Mar22.175616.1420@utzoo.uucp>
Organization: Galloway Research
Lines: 17

In article <1989Mar22.175616.1420@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In article <5845@mit-vax.LCS.MIT.EDU> keith@mit-vax.UUCP (Keith Packard) writes:
>>I'd rather see special blt hardware though.  I can imagine all sorts
>>of fun uses (like system/user data copy) for a fast piece of general
>>memory copy hardware.
>
>Before asking for copy hardware, find out whether your CPU is good enough
>(when programmed carefully) to saturate the memory bandwidth doing copying.

Its not quite that simple, since if the copy hardware runs direclty out
of memory (or has its own cache) then the CPU can be running in its own
cache and doing other useful work while the copy is going on, until the
copy is interrupted for the CPU to get another cache line.
apple!jrg	John R. Galloway, Jr.       contract programmer, San Jose, Ca

These are my views, NOT Apple's, I am a GUEST here, not an employee!!