Path: utzoo!utgpu!cunews!cognos!alzabo!andras
From: andras@alzabo.uucp (Andras Kovacs)
Newsgroups: comp.arch
Subject: Re: Acorn RISC Machine memory management
Keywords: ARM, Acorn, MMU, 4MB
Message-ID: <1990Sep25.071707.3641@alzabo.uucp>
Date: 25 Sep 90 07:17:07 GMT
References: <13942@hydra.gatech.EDU> <1990Sep24.194432.26087@watdragon.waterloo.edu>
Reply-To: andras@alzabo.UUCP (Andras Kovacs)
Organization: Brian's XENIXlings, Ottawa, Canada
Lines: 45


 Some news about Acorn, Archimedes and MMU:
  Acorn does have an ARM3 with 8 KB on-chip cache. It is available in 20 MHz
 and 30 MHz versions (2 micron and 1.5 micron is the difference). The faster
 one is roughly about 650 pounds (I mean on a card with the new - faster -
 MMU so you just plug it in); VERY steepy price indeed for North Americans 
 who are accustomed to IBM PC clone prices. But in your old Archimedes 310
 (with 8 MHz bus clock) it supposedly around 10-12 MIPS.
  So Acorn has that mentioned UNIX machine. They just announced a new non-UNIX
 one, the Archimedes A540. It has
    - ARM3 (30 MHz) with 12 MHz RAM speed
    - 4 MB RAM expandable to 16 MB by plug-in modules
      (they use their new MEMC - MMU - for it so they can drive it 12 MHz
       but one MEMC can handle only 4 MB. So they master-slave together max.
       five of them - one master and four slaves - which increases the max.
       RAM to 16 MB. But there they hit a hard limit; without redesigning the
       MEMC they cannot go beyond 16 MB)
    - 100 MB SCSI 18 ms drive
    - RISC-OS (not bad for an OS)
    - 13.5 MIPS
    - apparently it runs with standard VGA and SVGA monitors

 And now:

    !!! With (software) PC Emulator it runs as fast as an AT !!!

 Whoa!

 Price: 2995 pound sterling

 I have an A310 which I am very happy with; the only problem is to upgrade.
 I paid 200 pounds for a ST-506 hard drive controller (without drive :-) );
 some third party developers in England want around 575 pounds for a 4 MB
 upgrade card. I am doing 4 MB upgrade DIY but it is very tedious; I have
 to "remap" 7 pins on a 256x4 Kbit chip to match the pinout of a 64x4 Kbit
 one. And there is 32 of the suckers on the motherboard. Of course all 32
 chips are soldered into a 4-layer board; I succeeded to de-solder them and
 put in sockets but now I have to do the RAMs.

 Anyway, if anyone wants more info send me a mail.

 Egeszsegetekre

 Andras Kovacs
 ...@alzabo.andras