The Unix Heritage Society mailing list
 help / color / mirror / Atom feed
From: Arrigo Triulzi <arrigo@alchemistowl.org>
To: Paul Winalski <paul.winalski@gmail.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] Old mainframe I/O speed (was: core)
Date: Thu, 21 Jun 2018 16:49:21 +0200	[thread overview]
Message-ID: <CE5AFD89-9E9E-41DD-A243-6DD471B54B2A@alchemistowl.org> (raw)
In-Reply-To: <CABH=_VSzhumPL4xUfLpwpJRH9Qgv5TLy8M5ombeiw2VnGikdYg@mail.gmail.com>

On 21 Jun 2018, at 16:00, Paul Winalski <paul.winalski@gmail.com> wrote:
[...]
> for the microcode to customers.  There were several hacks in there to
> slow down the disk I/O so that it didn't outperform the model 30.

Is this the origin of the lore on “the IBM slowdown device”?

I seem to recall there was also some trickery at the CPU level so that you could “field upgrade” between two models by removing it but a) I cannot find the source and b) my Pugh book is far and cannot scan through it.

Arrigo 




  reply	other threads:[~2018-06-21 15:28 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-15 15:25 [TUHS] core Noel Chiappa
2018-06-15 23:05 ` Dave Horsfall
2018-06-15 23:22   ` Lyndon Nerenberg
2018-06-16  6:36     ` Dave Horsfall
2018-06-16 19:07       ` Clem Cole
2018-06-18  9:25         ` Tim Bradshaw
2018-06-19 20:45           ` Peter Jeremy
2018-06-19 22:55             ` David Arnold
2018-06-20  5:04               ` Peter Jeremy
2018-06-20  5:41                 ` Warner Losh
2018-06-20  8:10                   ` [TUHS] Old mainframe I/O speed (was: core) Greg 'groggy' Lehey
2018-06-20 16:33                     ` Paul Winalski
2018-06-21  3:05                       ` Peter Jeremy
2018-06-21 14:00                         ` Paul Winalski
2018-06-21 14:49                           ` Arrigo Triulzi [this message]
2018-06-21 20:39                             ` Paul Winalski
2018-06-22  5:32                               ` Erik E. Fair
2018-06-22 13:32                                 ` Clem Cole
2018-06-23  6:08                             ` Dave Horsfall
2018-06-23 17:02                               ` ron minnich
2018-06-22 13:11 Noel Chiappa
2018-06-22 17:49 ` Erik E. Fair
     [not found] <mailman.1.1529690481.3725.tuhs@minnie.tuhs.org>
2018-06-23 10:32 ` Johnny Billquist
2018-06-23 11:39   ` Clem cole
2018-06-24  7:50   ` Mutiny
2018-06-27 13:59     ` Clem Cole
2018-06-24  3:14 Norman Wilson
2018-06-24 13:03 ` Paul Winalski
2018-06-24 14:41   ` Lawrence Stewart
2018-06-24 15:47     ` Arthur Krewat
2018-06-24 18:49 Norman Wilson
2018-06-24 18:49 Norman Wilson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CE5AFD89-9E9E-41DD-A243-6DD471B54B2A@alchemistowl.org \
    --to=arrigo@alchemistowl.org \
    --cc=paul.winalski@gmail.com \
    --cc=tuhs@tuhs.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).