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From: arnold@skeeve.com
To: tuhs@minnie.tuhs.org, jnc@mercury.lcs.mit.edu
Cc: jnc@mercury.lcs.mit.edu
Subject: Re: [TUHS] Alternative Implementation Proposal for Unix/370 (BTL, 1979)
Date: Sat, 07 May 2022 13:03:42 -0600	[thread overview]
Message-ID: <202205071903.247J3gQD002051@freefriends.org> (raw)
In-Reply-To: <20220506153317.D499D18C07A@mercury.lcs.mit.edu>

Thanks Noel.

Those reasons are quite compelling. One gets the sense that they wanted
to get UNIX going on the 370 as quickly as posible.

jnc@mercury.lcs.mit.edu (Noel Chiappa) wrote:

>     > From: Tom Lyon
>
>     > there were a few icustomer nstallations. Bell Labs Indian Hill was one
>     > - so that's why TSS was the base of their UNIX port.
>
> "A UNIX System Implementation for System/370" (by W. A. Felton, G. L. Miller,
> and J. M. Milner):
>
>   https://www.bell-labs.com/usr/dmr/www/otherports/ibm.html
>
> says "code to support System/370 I/O, paging, error recording and recovery,
> and multiprocessing already existed in several available operating systems,
> we investigated the possibility of using an existing operating system, or at
> least the machine-interface parts of one, as a base to provide these
> functions for the System/370 implementation ... Of the available systems,
> TSS/370 came the closest to meeting our needs and was thus chosen as the base
> for our UNIX system implementation". Alas, it doesn't say which other systems
> were also considered.
>
>
>     >> On May 6, 2022, at 09:39, arnold@skeeve.com wrote:
>
>     >> So, why, given the letter from these folks, including DMR, did they go
>     >> ahead and use the TSS solution anyway?
>
> That paper says: "We initially thought about porting the UNIX operating
> system directly to System/370 with minimal changes. Unfortunately, there are
> a number of System/370 characteristics that, in the light of our objectives
> and resources, made such a direct port unattractive. The Input/Output (I/O)
> architecture of System/370 is rather complex; in a large configuration, the
> operating system must deal with a bewildering number of channels,
> controllers, and devices, many of which may be interconnected through
> multiple paths. Recovery from hardware errors is both complex and
> model-dependent. For hardware diagnosis and tracking, customer engineers
> expect the operating system to provide error logs in a specific format;
> software to support this logging and reporting would have to be written. ...
> Finally, several models of System/370 machines provide multiprocessing, with
> two (or more) processors operating with shared memory; the UNIX system did
> not support multiprocessing."
>
> Presumably these factors outweighed the factors listed in the
> Haley/London/Maranzaro/Ritchie letter.
>
> 	Noel

  reply	other threads:[~2022-05-07 19:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06 15:33 Noel Chiappa
2022-05-07 19:03 ` arnold [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-05-05 21:32 Tom Lyon via TUHS
2022-05-05 23:01 ` Adam Thornton
2022-05-06 22:54   ` Kevin Bowling
2022-05-06  7:35 ` arnold
2022-05-06  8:08   ` Ron Natalie
2022-05-06 14:21     ` Tom Lyon via TUHS
2022-05-06 15:51       ` Tom Ivar Helbekkmo via TUHS

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