Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Re: Re: A3000UX Seems Fated (Kill file alert!)
Message-ID: <17091@cbmvax.commodore.com>
Date: 3 Jan 91 23:03:33 GMT
References: <39228@nigel.ee.udel.edu> <1990Dec17.052316.19609@NCoast.ORG> <1990Dec24.220257.12208@ddsw1.MCS.COM> <1990Dec25.045537.13517@NCoast.ORG> <1990Dec25.234322.836@ddsw1.MCS.COM>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 45

In article <1990Dec25.234322.836@ddsw1.MCS.COM> karl@ddsw1.MCS.COM (Karl Denninger) writes:

>NEITHER the Amiga 3000 or the ISA machine will make a good server.  For that
>you need a real system bus, such as VME.  

The A3000 bus, like EISA and MCA, isn't all that slower than full 32 bit VME.
VME can kick up to about 66MB/s (as I recall).  Zorro III theoretical limits
(the numbers the VME, EISA, MCA, and NuBus people always give you) are 50 MB/s
for single cycle, 150 MB/s for burst cycles.  Typical values depend on the bus
master -- the A3000 bus master implementation itself hits around 20 MB/s for 
single cycles.  The A3000 local bus (where the 68030 and SCSI DMA sit) runs a
minimal 20 MB/s to memory, which maxes out at around 44 MB/s (on-page burst
to Fast RAM).  CPU slot expansion memory can go considerably faster.  

While you can clock a "PC-AT" bus faster, the Industry Standard Architecture
bus has a standard clock speed of 8MHz.  It is 16 bits wide, and a transfer
across it takes 4 clock cycles.  Thus, you have a basic 4 MB/s bus.  The A3000
will work as well as any personal computer and most workstations in an I/O
intensive environment.  No ISA bus machine even need apply.  As for what's
available now, VME would certainly win, since MCA and EISA are too new to have
a good number of high performance cards available, and Zorro III is even newer
still.

>I have no idea on the 3000UX -- but I'll bet ethernet performance will be 
>one of the sore spots.  Hell, ISA Ethernet is faster than Ethernet on MCA 
>systems!

Hmmm, I'm sure all them folks with RS/6000 systems would be a little surprised
by that comment.  It depends on who built the boards, of course.  The only
Ethernet boards available now for the A3000 are Zorro II boards, which of
course are slow, like ISA boards.  The C= board is a non-DMA board, which is
faster than the Ethernet boards we have in our PCs around here, but we most
likely don't have the fastest ISA ethernet boards available.  We also don't
have the fastest Amiga compatible ethernet boards either -- two third parties
(Hydra in England, who's board is marketed in the US by GVP, and ASDG) make
bus mastering Ethernet cards which you'd expect to be much faster.  

>Karl Denninger (karl@ddsw1.MCS.COM, <well-connected>!ddsw1!karl)


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
	"Don't worry, 'bout a thing. 'Cause every little thing, 
	 gonna be alright"		-Bob Marley