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From: "Ronald Natalie" <ron@ronnatalie.com>
To: "Kenneth Goodwin" <kennethgoodwin56@gmail.com>,
	"Will Senn" <will.senn@gmail.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: [TUHS] Re: Split addressing (I/D) space (inspired by the death of the python... thread)
Date: Thu, 03 Aug 2023 21:10:14 +0000	[thread overview]
Message-ID: <emc5ba4f43-13ab-4113-8ef3-3ed9c0d876a2@1984688d.com> (raw)
In-Reply-To: <CAMQbRb2e6ef5926wW=w=QjpzdHE2zSFa10jofdNH0b=dUkPOPg@mail.gmail.com>

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Having cut my UNIX teeth on the JHU 11/45, I can tell you very much that 
it did have split I/D.    V6 supported split I/D for user mode programs. 
   The kernel originally wasn’t split I/D.   Version 7, if I’m recalling 
properly, did run the kernel split I/D on the 45 and 70.



------ Original Message ------
From "Kenneth Goodwin" <kennethgoodwin56@gmail.com>
To "Will Senn" <will.senn@gmail.com>
Cc "The Eunuchs Hysterical Society" <tuhs@tuhs.org>
Date 8/3/23, 5:05:31 PM
Subject [TUHS] Re: Split addressing (I/D) space (inspired by the death 
of the python... thread)

>At the risk of exposing my ignorance and thus being events long long 
>ago in history....
>And my mind now old and feeble...
>
>😆 🤣
>
>1.  I don't think the 11/45 had split I & d.
>But I could be wrong.
>That did not appear until the 11/70
>And was in the later generation 11/44 several years later.
>
>2. The kernel determined it by MMU type and managed it solely. The 
>assembler and loader always built the binary object file as the three 
>sections - instructions,  data and bss spaces so loading an object file 
>could be done on any platform.
>Programmers generally did not worry about the underlying hardware
>
>3. I don't recall if a systype style system call was available in v7 to 
>give you a machine type to switch off of.
>
>With something like that you could determine memory availability hard 
>limits on the DATA/bss side if you needed to.
>
>But that was also easily determined by a allocation failure in 
>malloc/sbrk with an out of memory error.
>
>If you really needed to know availability,  you could have a start up 
>subroutine that would loop trying to malloc ever decreasing memory 
>sizes until success and until out of available memory error.
>Then release it all back via free(). Or manage it internally.
>
>As I recall however vaguely,  there was an attempt to split the kernel 
>into two pieces. One running in kernel mode and one running in 
>supervisor mode in order to double the amount of available  instruction 
>and data spaces for the operating system. I recall playing around with 
>what was there trying to get it to work right.
>I was trying to support over 200 users on a pdp 11/70 at the time 
>running a massive insurance database system.
>
>On Thu, Aug 3, 2023, 4:35 PM Will Senn <will.senn@gmail.com> wrote:
>>Does unix (v7) know about the PDP-11 45's split I/D space through
>>configuration or is it convention and programmer's responsibility to
>>know and manage what's actually available?
>>
>>Will
>>
>>On 8/3/23 12:00, Rich Salz wrote:
>> > What, we all need something to kick now that we've beaten sendmail?
>> > How about something unix, ideally a decade old?
>>

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  reply	other threads:[~2023-08-03 21:10 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-30 18:22 [TUHS] Re: Cool talk on Unix and Sendmail history, by Eric Allman Norman Wilson
2023-07-30 21:43 ` Rob Pike
2023-07-30 23:34   ` George Michaelson
2023-07-30 23:59     ` Erik E. Fair
2023-07-31  0:26       ` Warner Losh
2023-07-31 22:57         ` Grant Taylor via TUHS
2023-07-31 23:05           ` Warner Losh
2023-08-01  2:45             ` Grant Taylor via TUHS
2023-08-01  1:51         ` Niklas Karlsson
2023-08-01  2:47           ` Grant Taylor via TUHS
2023-08-01  3:20           ` Theodore Ts'o
2023-07-31  0:41       ` segaloco via TUHS
2023-08-01  9:22       ` Marc Donner
2023-08-01 10:58         ` Erik E. Fair
2023-08-02  0:37           ` Dave Horsfall
2023-08-02 14:52             ` Ron Natalie
2023-08-02 21:14               ` Grant Taylor via TUHS
2023-08-02 22:20                 ` segaloco via TUHS
2023-08-02 22:37                   ` Warner Losh
2023-08-02 23:49                   ` Rich Salz
2023-08-03  0:51                     ` [TUHS] Re: python Larry McVoy
2023-08-03  1:20                       ` George Michaelson
2023-08-03  2:53                         ` Bakul Shah
2023-08-03  2:55                         ` segaloco via TUHS
2023-08-03  3:24                         ` George Michaelson
2023-08-03  3:32                           ` Warner Losh
2023-08-03  3:55                           ` Bakul Shah
2023-08-03  8:32                             ` Rob Pike
2023-08-03 14:19                               ` Bakul Shah
2023-08-03 14:56                                 ` Dan Halbert
2023-08-03 15:20                                   ` will.senn
2023-08-03 22:05                                     ` Dan Cross
2023-08-04  0:24                                       ` John Cowan
2023-08-04 15:17                                         ` Dan Cross
2023-08-05  4:44                                       ` Bakul Shah
2023-08-03 15:41                                 ` John Cowan
2023-08-03  2:07                       ` Clem Cole
2023-08-03  2:21                         ` Pete Wright via TUHS
2023-08-03  2:56                           ` Warner Losh
2023-08-03 12:36                         ` Mike Markowski
2023-08-03 13:29                           ` Rob Pike
2023-08-03 15:24                             ` emanuel stiebler
2023-08-03 15:39                               ` Steffen Nurpmeso
2023-08-04  1:01                             ` Larry McVoy
2023-08-04  1:28                               ` segaloco via TUHS
2023-08-04  1:58                                 ` Adam Thornton
2023-08-04 15:04                                   ` Dan Cross
2023-08-04 15:10                                     ` Larry McVoy
2023-08-03 16:57                         ` [TUHS] Re: [TULSA] " Phil Budne
2023-08-03 17:00                           ` Rich Salz
2023-08-03 20:35                             ` [TUHS] Split addressing (I/D) space (inspired by the death of the python... thread) Will Senn
2023-08-03 21:05                               ` [TUHS] " Kenneth Goodwin
2023-08-03 21:10                                 ` Ronald Natalie [this message]
2023-08-03 21:16                                   ` Warner Losh
2023-08-03 21:24                                     ` Ronald Natalie
2023-08-03 22:34                                   ` Kenneth Goodwin
2023-08-03 21:05                               ` Ronald Natalie
2023-08-03 21:44                               ` Clem Cole
2023-08-03 22:08                                 ` Will Senn
2023-08-03 22:54                                   ` Clem Cole
2023-08-03 23:08                                     ` Dave Horsfall
2023-08-03 23:15                                     ` Clem Cole
2023-08-04  0:38                                     ` John Cowan
2023-08-03 17:29                           ` [TUHS] Re: [TULSA] Re: python Alejandro Colomar
2023-08-03 17:51                             ` John Cowan
2023-08-03 18:05                               ` Alejandro Colomar
2023-08-03 21:29                                 ` Dan Cross
2023-08-03 23:55                                   ` [TUHS] printf (was: python) Alejandro Colomar
2023-08-04 16:06                                     ` [TUHS] " Dan Cross
2023-08-04 16:57                                       ` Alejandro Colomar
2023-08-04 21:16                                         ` Dan Cross
2023-08-03 21:02                           ` [TUHS] Re: [TULSA] Re: python Steffen Nurpmeso
2023-08-03 23:47                           ` Larry McVoy
2023-08-03 23:54                             ` Will Senn
2023-08-04 19:20                         ` [TUHS] " Ed Bradford
2023-08-04 19:47                           ` Larry McVoy
2023-08-05  5:40                             ` Ed Bradford
2023-08-02 23:33               ` [TUHS] Re: Cool talk on Unix and Sendmail history, by Eric Allman Dave Horsfall
2023-08-03 21:48 [TUHS] Re: Split addressing (I/D) space (inspired by the death of the python... thread) Noel Chiappa
2023-08-03 23:10 Noel Chiappa
2023-08-03 23:42 ` Warner Losh
2023-08-03 23:14 Steve Simon
2023-08-04 21:40 Noel Chiappa

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