Groups > sci.electronics.design > #453722

Re: big drives

From	Don Y <blockedofcourse@foo.invalid>
Newsgroups	sci.electronics.design
Subject	Re: big drives
Date	2017-03-26 03:33 -0700
Organization	A noiseless patient Spider
Message-ID	<ob8598$raa$1@dont-email.me> (permalink)
References	(7 earlier) <0i0ddc1dokesujr1qfen6ojbrvb72b2ui6@4ax.com> <ob6alq$74v$1@dont-email.me> <fimddclg0mijti8fqhe4jh6q9acju8cml2@4ax.com> <ob6pue$om4$1@dont-email.me> <0d1fdchip2tev0pjl2gfjp8bd1qnqkko4e@4ax.com>

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On 3/26/2017 2:18 AM, upsidedown@downunder.com wrote:
> On Sat, 25 Mar 2017 15:14:19 -0700, Don Y
> <blockedofcourse@foo.invalid> wrote:
>
>> On 3/25/2017 2:11 PM, upsidedown@downunder.com wrote:
>>> On Sat, 25 Mar 2017 10:53:42 -0700, Don Y
>>> <blockedofcourse@foo.invalid> wrote:
>>>
>>>> On 3/25/2017 7:54 AM, John Larkin wrote:
>>>>> The PDP-11 was a 16-bit machine programmed in octal. Because it had 8
>>>>> registers, octal worked. I could once compile instruction to octal by
>>>>> sight; I probably still can do some. It fit beautifully.
>>>
>>> I programmed a lot of diagnostic code into the PDP-11 using front
>>> panel (binary) switches. That was quite easy. The problem was entering
>>> the branch instruction offsets, especially backwards, when you had to
>>> calculate the negative offset and had to consider the actual value of
>>> the PC, when the branch was taken.
>>
>> And, remembering "specialty" opcodes (e.g., INTDS) that didn't fit a nice
>> "decoding pattern".
>>
>>>> This was true of a lot of machines.  I used to bit-switch diagnostics
>>>> into Novas by just writing the code in my head and "assembling" it
>>>> as the nerve impulses traveled down to my fingertips before hitting the
>>>> DEP-NEXT toggle.
>>>
>>> The Nova was a 74181 ALU chip with steroids :-)
>>>
>>>> Worked at a place that had *heated* arguments as to whether to
>>>> "hand-assemble" code for the Z80 in hex or octal (a large swath
>>>> of the opcode space -- e.g., all the load/store group -- could be
>>>> easily mapped onto an octal representation).  I just shook
>>>> my head and asked:  "Why not let the *machine* remember all
>>>> those details CORRECTLY and reference things SYMBOLICALLY??"
>>>
>>> The 8080 (and hence Z80) are basically octal machines. I do not
>>> understand why Intel switched to hex after initially using octals.
>>
>> How is it -- or any machine -- an "octal" machine vs. a hexadecimal
>> machine vs. a binary machine vs. ...?  Does it process data in groups
>> of three bits -- instead of four?  or 8?  or 1?
>
> Then there were also decimal computers used for accounting etc.
> I once wrote a cross assembler for a Philips  machine with exactly
> 1000 memory words, each of which IIRC was 10 decimal digits

But you don't need a "decimal computer" to do decimal arithmetic.
And, an "octal computer" doesn't do "octal arithmetic" -- any
more than it does "hexadecimal arithmetic".

Thread

big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-21 10:21 -0700
  Re: big drives bitrex <bitrex@de.lete.earthlink.net> - 2017-03-21 13:47 -0400
    Re: big drives George Herold <gherold@teachspin.com> - 2017-03-21 12:42 -0700
      Re: big drives dagmargoodboat@yahoo.com - 2017-03-21 12:55 -0700
        Re: big drives George Herold <gherold@teachspin.com> - 2017-03-21 13:37 -0700
          Re: big drives bill.sloman@ieee.org - 2017-03-21 21:51 -0700
            Re: big drives George Herold <gherold@teachspin.com> - 2017-03-22 07:26 -0700
  Re: big drives Winfield Hill <hill@rowland.harvard.edu> - 2017-03-22 03:38 -0700
    Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-22 14:23 +0000
      Re: big drives David Brown <david.brown@hesbynett.no> - 2017-03-22 16:43 +0100
        Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-22 18:35 +0000
          Re: big drives David Brown <david.brown@hesbynett.no> - 2017-03-23 10:24 +0100
            Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-23 16:11 +0000
              Re: big drives krw@notreal.com - 2017-03-23 13:05 -0400
                Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-23 17:39 +0000
                Re: big drives krw@notreal.com - 2017-03-23 21:05 -0400
                Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-24 03:01 +0000
                Re: big drives krw@notreal.com - 2017-03-23 23:09 -0400
                Re: big drives Don Kuenz <g@crcomp.net> - 2017-03-24 04:15 +0000
                Re: big drives krw@notreal.com - 2017-03-24 22:34 -0400
      Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 12:25 -0700
        Re: big drives dplatt@coop.radagast.org (Dave Platt) - 2017-03-22 13:57 -0700
          Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 16:03 -0700
        Re: big drives krw@notreal.com - 2017-03-22 20:29 -0400
  Re: big drives tabbypurr@gmail.com - 2017-03-22 04:36 -0700
    Re: big drives Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-03-22 08:57 -0400
      Re: big drives Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-22 11:59 -0400
        Re: big drives krw@notreal.com - 2017-03-22 13:23 -0400
          Re: big drives Jon Elson <jmelson@wustl.edu> - 2017-03-22 16:38 -0500
            Re: big drives krw@notreal.com - 2017-03-22 20:31 -0400
            Re: big drives gray_wolf <g_wolf@nospam.com> - 2017-03-23 20:59 -0500
            Re: big drives gray_wolf <g_wolf@nospam.com> - 2017-03-23 21:00 -0500
        Re: big drives Robert Baer <robertbaer@localnet.com> - 2017-03-23 22:21 -0800
    Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-22 07:51 -0700
      Re: big drives krw@notreal.com - 2017-03-22 13:23 -0400
      Re: big drives Robert Baer <robertbaer@localnet.com> - 2017-03-23 22:19 -0800
      Re: big drives tabbypurr@gmail.com - 2017-03-24 04:26 -0700
        Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 08:38 -0700
    Re: big drives Jon Elson <jmelson@wustl.edu> - 2017-03-22 16:37 -0500
      Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-22 16:07 -0700
        Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 16:21 -0700
          Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-22 16:45 -0700
            Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 23:21 -0700
              Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 13:06 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 16:56 -0700
                Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 17:35 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 21:47 -0700
      Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 16:19 -0700
        Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-22 16:50 -0700
          Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 17:58 -0700
            Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-22 21:00 -0700
              Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-22 22:50 -0700
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-23 08:27 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 12:25 -0700
      Re: big drives tabbypurr@gmail.com - 2017-03-24 04:31 -0700
        Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 06:38 -0700
          Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 08:41 -0700
            Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 11:38 -0700
              Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 13:55 -0700
              Re: big drives tabbypurr@gmail.com - 2017-03-24 17:14 -0700
                Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 17:41 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 18:00 -0700
  Re: big drives Joerg <news@analogconsultants.com> - 2017-03-23 09:35 -0700
  Re: big drives "Michael A. Terrell" <mike.terrell@earthlink.net> - 2017-03-23 18:38 -0400
    Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 16:18 -0700
      Re: big drives Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-23 18:29 -0400
        Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 18:38 -0700
          Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 18:54 -0700
            Re: big drives pcdhobbs@gmail.com - 2017-03-23 19:16 -0700
              Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 19:28 -0700
                Re: big drives pcdhobbs@gmail.com - 2017-03-23 19:55 -0700
                Re: big drives krw@notreal.com - 2017-03-23 23:04 -0400
                Re: big drives pcdhobbs@gmail.com - 2017-03-23 22:00 -0700
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 08:46 -0700
                Re: big drives krw@notreal.com - 2017-03-24 22:38 -0400
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-23 22:22 -0700
                Re: big drives pcdhobbs@gmail.com - 2017-03-23 23:08 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 00:21 -0700
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 09:00 -0700
                Re: big drives David Brown <david.brown@hesbynett.no> - 2017-03-24 17:14 +0100
                Re: big drives tabbypurr@gmail.com - 2017-03-24 09:19 -0700
                Re: big drives David Brown <david.brown@hesbynett.no> - 2017-03-24 17:47 +0100
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 12:01 -0700
                Re: big drives Jasen Betts <jasen@xnet.co.nz> - 2017-03-24 20:30 +0000
                Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 14:06 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 11:55 -0700
                Re: big drives "Michael A. Terrell" <mike.terrell@earthlink.net> - 2017-03-25 04:00 -0400
                Re: big drives upsidedown@downunder.com - 2017-03-24 22:18 +0200
                Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 14:15 -0700
                Re: big drives Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-25 13:21 +0200
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-25 07:54 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-25 10:53 -0700
                Re: big drives upsidedown@downunder.com - 2017-03-25 23:11 +0200
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-25 15:14 -0700
                Re: big drives upsidedown@downunder.com - 2017-03-26 12:18 +0300
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-26 03:33 -0700
                Re: big drives Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-26 16:36 -0400
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-26 14:13 -0700
                Re: big drives Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-25 21:04 +0200
                Re: big drives pcdhobbs@gmail.com - 2017-03-24 19:03 -0700
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 08:53 -0700
                Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 12:12 -0700
                Re: big drives John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-24 14:20 -0700
                Re: big drives krw@notreal.com - 2017-03-24 22:43 -0400
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 20:10 -0700
                Re: big drives krw@notreal.com - 2017-03-24 23:23 -0400
                Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-24 22:25 -0700
                Re: big drives Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-25 13:23 +0200
        Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-23 19:36 -0700
      Re: big drives upsidedown@downunder.com - 2017-03-24 10:14 +0200
        Re: big drives Don Y <blockedofcourse@foo.invalid> - 2017-03-24 01:31 -0700
    Re: big drives John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-23 16:21 -0700
      Re: big drives "Michael A. Terrell" <mike.terrell@earthlink.net> - 2017-03-24 08:54 -0400

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