Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: A4000,Lotus,Microsoft,UNIX...
Message-ID: <14898@cbmvax.commodore.com>
Date: 5 Oct 90 03:59:50 GMT
References: <32040@nigel.ee.udel.edu> <22345@grebyn.com> <2040@jimi.cs.unlv.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 40

In article <2040@jimi.cs.unlv.edu> maniac@hammond.cs.unlv.edu (Eric J. Schwertfeger) writes:
>In article <22345@grebyn.com>, ckp@grebyn.com (Checkpoint Technologies) writes:
>|> heard); superficialy it resembles the A3000 and in fact beats it "by
>|> the numbers": 32MHz 68030, 4 Meg RAM,

>Ah, but what they don't tell you is that all 4 Meg, and any expansion
>memory, is the equivelent of the Amiga's Chip Ram.  Sounds good, until
>you realize that the video eats half of the memory bandwidth, apparently
>regardless of video mode.  

Really?  I though they would have some equivalent to Fast memory.  Of course,
that was just a natural assumption based on what's necessary to make things
go fast.  Though at 32MHz, if they're supplying anything slower than 60ns
RAM, the CPU clock speed is likely far more for spec sheets and marketing than
any actual user benefit.  

When Apple went to an integrated, flexible video chip (on the IIci), they 
shipped the machine with video memory, which acts much like our Chip memory,
and actually gets most of its bandwidth devoted to video fetch if you set
up a 640x480x8 display.  However, this "A" memory can be augmented by "B"
memory, which is equivalent to Fast memory on an Amiga.  

Most systems these days don't permit expansion memory beyond the 16Meg or 
thereabouts available on the motherboard, so they only cope with these
two basic memory types.  The A3000 can actually support 4 possible types
of Fast memory; as well as on-board Fast, there's CPU Slot memory, Zorro III
memory, and Zorro II memory.  If A3000 on-board memory is "Fast", you
might call CPU slot memory "Faster", Zorro III memory "Not quite as Fast",
and Zorro II memory "We used to think this was Fast".  That's essentially
the way that 2.0 treats them, though there's only an ordering
distinction in the memory lists; they're all considered Fast, as in, 
not Chip-bus-delayed.

>Eric J. Schwertfeger, maniac@jimi.cs.unlv.edu


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
	Standing on the shoulders of giants leaves me cold	-REM