Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.arch > #110110

Re: What is an N-bit machine?

From Lynn Wheeler <lynn@garlic.com>
Newsgroups comp.arch
Subject Re: What is an N-bit machine?
Date 2024-11-28 11:45 -1000
Organization Wheeler&Wheeler
Message-ID <87jzcnyqv1.fsf@localhost> (permalink)
References <memo.20241128153105.12904U@jgd.cix.co.uk>

Show all headers | View raw


jgd@cix.co.uk (John Dallman) writes:
> In early computer designs, arithmetic registers were much longer than
> addresses, the classic examples being machines with 36-bit words and 15-
> to 18-bit addresses. 
>
> Large logical address spaces started with the IBM 360, which had 32-bit
> arithmetic registers and 32-bit address registers. You couldn't put
> 32-bits worth of physical memory in a machine for over a decade after it
> appeared, but it was allowed for in the architecture.

360 had 32bit registers but addressing only used 24bits (16mbyte)
... except for 360/67 virtual memory mode which had 32bit addressing
(when got around to adding virtual memory to all 370s, it was only 24bit
addressing ... it wasn't until the 80s with 370/xa that 31bit addressing
was introduced). 360/67 also allowed for all (multiprocessor) CPUs to
address all channels (360/65 multiprocessor and later 370 multiprocessor
simulated multiprocessor I/O with multi-channel controllers connected to
different dedicated processor channels at the same address).

360/67
https://bitsavers.org/pdf/ibm/360/functional_characteristics/A27-2719-0_360-67_funcChar.pdf
https://bitsavers.org/pdf/ibm/360/functional_characteristics/GA27-2719-2_360-67_funcChar.pdf

Before 370/xa, MVS was getting so bloated that they did hack to 3033 for
64mbyte real memory ... still 24bit (real & virtual) instruction
addressing ... but they scavanged two unused bits in the virtual memory
16bit PTE, used to prefix the 12bit page numbers (4096 4096byte pages
... 16mbyte) for 14bit page numbers (16384 4096byte pages) aka
translating 24bit (virtual) addresses into 26bit (real) addresses
(64mbytes) ... pending 370/xa and 31bit

-- 
virtualization experience starting Jan1968, online at home since Mar1970

Back to comp.arch | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

What is an N-bit machine? jgd@cix.co.uk (John Dallman) - 2024-11-28 15:31 +0000
  Re: What is an N-bit machine? scott@slp53.sl.home (Scott Lurndal) - 2024-11-28 16:33 +0000
  Re: What is an N-bit machine? Michael S <already5chosen@yahoo.com> - 2024-11-28 18:55 +0200
    Re: What is an N-bit machine? John Levine <johnl@taugh.com> - 2024-11-30 02:37 +0000
      Re: What is an N-bit machine? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2024-11-29 22:30 -0800
        Re: What is an N-bit machine? John Levine <johnl@taugh.com> - 2024-11-30 19:40 +0000
          Re: What is an N-bit machine? Michael S <already5chosen@yahoo.com> - 2024-11-30 22:38 +0200
            Re: What is an N-bit machine? "Paul A. Clayton" <paaronclayton@gmail.com> - 2024-12-01 11:23 -0500
              Re: What is an N-bit machine? scott@slp53.sl.home (Scott Lurndal) - 2024-12-01 19:52 +0000
          Re: What is an N-bit machine? mitchalsup@aol.com (MitchAlsup1) - 2024-11-30 22:39 +0000
            Re: What is an N-bit machine? Thomas Koenig <tkoenig@netcologne.de> - 2024-12-01 08:19 +0000
              Re: What is an N-bit machine? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-01 08:35 +0000
            Re: What is an N-bit machine? Terje Mathisen <terje.mathisen@tmsw.no> - 2024-12-02 09:48 +0100
              Re: What is an N-bit machine? "Brian G. Lucas" <bagel99@gmail.com> - 2024-12-02 19:56 -0500
                Re: What is an N-bit machine? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2024-12-03 00:01 -0800
              Re: What is an N-bit machine? antispam@fricas.org (Waldek Hebisch) - 2024-12-15 18:20 +0000
      Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-30 06:28 +0000
        Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-30 11:35 +0000
          Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2024-11-30 11:58 +0000
            Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-30 16:57 +0000
              Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Michael S <already5chosen@yahoo.com> - 2024-11-30 19:32 +0200
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-30 18:08 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Michael S <already5chosen@yahoo.com> - 2024-11-30 20:28 +0200
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-01 09:28 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2024-12-01 14:03 +0000
                Re: Keeping other stuff with addresses David Schultz <david.schultz@earthlink.net> - 2024-12-01 08:15 -0600
                Re: Keeping other stuff with addresses Thomas Koenig <tkoenig@netcologne.de> - 2024-12-01 14:40 +0000
                Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-04 02:19 +0000
                Re: Keeping other stuff with addresses John Levine <johnl@taugh.com> - 2024-12-04 03:25 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-01 07:32 -0800
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2024-12-01 17:53 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Michael S <already5chosen@yahoo.com> - 2024-12-01 20:05 +0200
                Re: Keeping other stuff with addresses EricP <ThatWouldBeTelling@thevillage.com> - 2024-12-01 18:16 -0500
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Brett <ggtgp@yahoo.com> - 2024-12-01 20:02 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-31 08:54 -0800
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-01 15:28 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-01-01 17:39 -0800
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-02 09:59 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-01-08 10:00 -0800
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2025-01-08 19:18 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-01-27 17:05 -0800
                Re: Keeping other stuff with addresses David Brown <david.brown@hesbynett.no> - 2025-01-28 08:30 +0100
                Re: Keeping other stuff with addresses Thomas Koenig <tkoenig@netcologne.de> - 2025-02-02 08:37 +0000
                Re: Keeping other stuff with addresses Terje Mathisen <terje.mathisen@tmsw.no> - 2024-12-02 17:10 +0100
                Re: Keeping other stuff with addresses Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-31 08:46 -0800
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) John Levine <johnl@taugh.com> - 2024-11-30 19:12 +0000
                What is an N-bit machine? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-01 08:41 +0000
                Re: What is an N-bit machine? scott@slp53.sl.home (Scott Lurndal) - 2024-12-01 15:52 +0000
                Re: What is an N-bit machine? antispam@fricas.org (Waldek Hebisch) - 2024-12-16 22:39 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) Thomas Koenig <tkoenig@netcologne.de> - 2024-11-30 22:06 +0000
                Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-01 08:38 +0000
        Re: Keeping other stuff with addresses (was: What is an N-bit machine?) scott@slp53.sl.home (Scott Lurndal) - 2024-11-30 17:57 +0000
          Re: Keeping other stuff with addresses (was: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-01 09:38 +0000
        Re: Keeping other stuff with addresses "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-01 15:22 -0800
          Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-02 01:26 +0000
            Re: Keeping other stuff with addresses "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-01 20:12 -0800
              Re: Keeping other stuff with addresses "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-02 16:54 -0800
                Re: Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-03 11:51 -0500
                Re: Keeping other stuff with addresses John Levine <johnl@taugh.com> - 2024-12-03 18:19 +0000
                Re: Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-03 13:46 -0500
                Re: Keeping other stuff with addresses John Levine <johnl@taugh.com> - 2024-12-03 23:33 +0000
                Re: Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-03 18:52 -0500
                Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-04 02:36 +0000
                Re: Keeping other stuff with addresses Thomas Koenig <tkoenig@netcologne.de> - 2024-12-04 06:29 +0000
                Re: Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-04 10:32 -0500
                Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-04 19:47 +0000
                Re: Keeping other stuff with addresses Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-04 15:47 -0800
                Re: Keeping other stuff with addresses scott@slp53.sl.home (Scott Lurndal) - 2024-12-04 16:31 +0000
                Re: bytes, Keeping other stuff with addresses John Levine <johnl@taugh.com> - 2024-12-05 00:39 +0000
                unaligned load/store (was: Re: Keeping other stuff with addresses) Jonathan Thornburg <jonathan@gold.bkis-orchard.net> - 2024-12-21 23:22 +0000
                Re: unaligned load/store mitchalsup@aol.com (MitchAlsup1) - 2024-12-22 01:27 +0000
                Re: unaligned load/store Thomas Koenig <tkoenig@netcologne.de> - 2024-12-22 10:01 +0000
                Re: unaligned load/store anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-22 11:06 +0000
                Re: unaligned load/store jgd@cix.co.uk (John Dallman) - 2024-12-22 11:42 +0000
                Re: unaligned load/store "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-22 19:41 -0800
                Re: unaligned load/store Thomas Koenig <tkoenig@netcologne.de> - 2024-12-22 21:04 +0000
                Re: unaligned load/store mitchalsup@aol.com (MitchAlsup1) - 2024-12-22 23:32 +0000
                Re: unaligned load/store Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-26 13:38 -0500
                Re: unaligned load/store George Neuner <gneuner2@comcast.net> - 2024-12-26 16:31 -0500
                Re: unaligned load/store mitchalsup@aol.com (MitchAlsup1) - 2024-12-26 21:59 +0000
                Re: unaligned load/store "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-26 14:05 -0800
                Re: unaligned load/store (was: Re: Keeping other stuff with addresses) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-12-22 10:33 +0000
                Re: bits and bytes, Keeping other stuff with addresses John Levine <johnl@taugh.com> - 2024-12-04 03:39 +0000
                Re: bits and bytes, Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-04 10:36 -0500
                Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-03 19:22 +0000
                Re: Keeping other stuff with addresses "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-03 17:03 -0800
                Re: Keeping other stuff with addresses "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-03 16:56 -0800
                Re: Keeping other stuff with addresses Stefan Monnier <monnier@iro.umontreal.ca> - 2024-12-04 10:37 -0500
        Re: Keeping other stuff with addresses Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-12-03 17:43 -0800
          Re: Keeping other stuff with addresses mitchalsup@aol.com (MitchAlsup1) - 2024-12-04 02:42 +0000
  Re: What is an N-bit machine? Thomas Koenig <tkoenig@netcologne.de> - 2024-11-28 17:56 +0000
    Re: What is an N-bit machine? mitchalsup@aol.com (MitchAlsup1) - 2024-11-28 19:02 +0000
      Re: What is an N-bit machine? Brett <ggtgp@yahoo.com> - 2024-11-28 19:39 +0000
    Re: What is an N-bit machine? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-28 21:42 +0000
      Re: What is an N-bit machine? jgd@cix.co.uk (John Dallman) - 2024-11-28 22:08 +0000
        Re: What is an N-bit machine? Lynn Wheeler <lynn@garlic.com> - 2024-11-28 12:44 -1000
          Re: What is an N-bit machine? jgd@cix.co.uk (John Dallman) - 2024-11-28 22:58 +0000
          IBM and Amdahl history (Re: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-29 07:22 +0000
            Re: IBM and Amdahl history (Re: What is an N-bit machine?) Lynn Wheeler <lynn@garlic.com> - 2024-11-29 08:24 -1000
            Re: IBM and Amdahl history (Re: What is an N-bit machine?) scott@slp53.sl.home (Scott Lurndal) - 2024-11-29 18:29 +0000
            Re: IBM and Amdahl history (Re: What is an N-bit machine?) Lynn Wheeler <lynn@garlic.com> - 2024-11-29 11:51 -1000
            Re: IBM and Amdahl history (Re: What is an N-bit machine?) Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-29 21:51 +0000
              Re: IBM and Amdahl history (Re: What is an N-bit machine?) scott@slp53.sl.home (Scott Lurndal) - 2024-11-30 17:45 +0000
                Re: IBM and Amdahl history (Re: What is an N-bit machine?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-30 18:19 +0000
                Re: IBM and Amdahl history (Re: What is an N-bit machine?) jgd@cix.co.uk (John Dallman) - 2024-11-30 22:19 +0000
                Re: IBM and Amdahl history (Re: What is an N-bit machine?) Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-30 23:21 +0000
        Re: What is an N-bit machine? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-11-29 02:17 +0000
          Re: What is an N-bit machine? Brett <ggtgp@yahoo.com> - 2024-11-30 01:29 +0000
          Re: market power, What is an N-bit machine? John Levine <johnl@taugh.com> - 2024-11-30 02:42 +0000
          Re: What is an N-bit machine? Lynn Wheeler <lynn@garlic.com> - 2024-11-29 17:42 -1000
  Re: What is an N-bit machine? mitchalsup@aol.com (MitchAlsup1) - 2024-11-28 19:01 +0000
  Re: What is an N-bit machine? Lynn Wheeler <lynn@garlic.com> - 2024-11-28 11:45 -1000
  Re: What is an N-bit machine? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2024-11-29 08:03 +0000
    Re: What is an N-bit machine? Thomas Koenig <tkoenig@netcologne.de> - 2024-11-29 19:17 +0000
    Re: What is an N-bit machine? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-12-22 21:37 +0000

csiph-web