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Groups > sci.electronics.design > #453554

Re: big drives

From John Larkin <jjlarkin@highlandtechnology.com>
Newsgroups sci.electronics.design
Subject Re: big drives
Date 2017-03-25 07:54 -0700
Organization highland technology
Message-ID <0i0ddc1dokesujr1qfen6ojbrvb72b2ui6@4ax.com> (permalink)
References (7 earlier) <ob2h95$obg$1@dont-email.me> <59gadc55dm58qr5q9eqn5q67vabhblf949@4ax.com> <hvuadc9h9tbsdg49v4pqu43v6l8u9gcbbj@4ax.com> <kl2bdc9jid0ukj8ptvc5m53lg5cmd396ih@4ax.com> <ob5jlh$s0q$1@dont-email.me>

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On Sat, 25 Mar 2017 13:21:05 +0200, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:

>On 24.3.17 23:15, John Larkin wrote:
>> On Fri, 24 Mar 2017 22:18:48 +0200, upsidedown@downunder.com wrote:
>>
>>> On Fri, 24 Mar 2017 09:00:57 -0700, John Larkin
>>> <jjlarkin@highlandtechnology.com> wrote:
>>>
>>>> On Fri, 24 Mar 2017 00:21:50 -0700, Don Y
>>>> <blockedofcourse@foo.invalid> wrote:
>>>>
>>>>> On 3/23/2017 11:08 PM, pcdhobbs@gmail.com wrote:
>>>>>>> How much did you part with for the kit YOU were using in the mid 70's?
>>>>>>
>>>>>> Your reference was from 1970,
>>>>>
>>>>> No, the MANUAL that I referenced was from 1970.  My reference to the
>>>>> *equipment* was:
>>>>>     "My first *hard* disk had a capacity of 256K words..."
>>>>> John Larkin referenced 1970 (feel free to check back up-thread)
>>>>>
>>>>>> when I was 10 years old and had just got a
>>>>>> soldering gun and some plumber's solder for my birthday. (My parents were
>>>>>> very supportive but didn't know much about radio. The debt I owe them has
>>>>>> hopefully been paid to the next generation.)
>>>>>>
>>>>>> Soon after that point I had to save up a month's pocket money plus what I
>>>>>> earned from extra chores to buy parts to build projects with.
>>>>>
>>>>> I built my first computers from "samples" begged from sales reps (while
>>>>> working my way through school).  And, from bits of kit gifted to me by friends
>>>>> who worked at firms like DEC (I could never afford to buy even USED kit of this
>>>>> sort AND arrange to pay my tuition, rent, board, etc.)
>>>>
>>>> The first (and only) computer that I actually designed was two boards
>>>> full of TTL. It had three instructions and a 20 KHz 4-phase clock.
>>>>
>>>> Everybody should design a CPU just once, even as a mental activity.
>>>
>>> Look at the original Data General Nova computer, which was designed
>>> around the 74181 ALU chip :-).
>>
>> It was a 4-bit architecture, multiple clocking one ALU to get to 16
>> bit data and instructions. Steve Wozniak said that he learned digital
>> design by studying the Nova schematics.
>>
>> The Nova, and the HP2114, were basically 16-bit PDP8s; an accumulator
>> or two, paged memory, conditional skips. DEC was going to do that, but
>> one late beer session invented the PDP-11 architecture, which was far
>> superior. I think the PDP-11 inspired the 68K.
>
>
>There were 4 accumulators on the Nova. There are rumors that the Nova
>was what should be PDP-11, but DEC delayed it to prevent problems to
>PDP-8 sales, and the guys spun off to found Data General.

That's the story, except that Gordon Bell and Rick Merrill and people
then had time (rumored to be one late-night session at Bell's house)
to think it over and come up with a new architecture.

>
>The PDP-11 did inspire the Motorola chip designers, but it went via
>the 6800 and 6809 until the 68K.
>
>There were 8 general registers on the PDP-11, but the idea was nothing
>new at that time: already the IBM S/360 had general registers.

I think s/360 probably inspired parts of the PDP-11 architecture.

The PDP11/20 (I got a very early one) was all TTL, about 510 MSI chips
on two big boards. It was all hard logic, no microcode, and was done
in the classic DEC hairball logic design style: a tangle of async
clocks, one-shots, RCs, tapped delay lines. There were some short
instruction sequences that would lock it up hard. Later on somebody
taught them about synchronous state machines and microcoding.

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.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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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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