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From: Perry Smith <pedz@easesoftware.com>
To: zsh-users@zsh.org
Subject: Re: Parallel processing
Date: Mon, 28 Mar 2022 08:47:18 -0500	[thread overview]
Message-ID: <1193520F-22B1-4786-AA20-E9B0FE9D1596@easesoftware.com> (raw)
In-Reply-To: <20220327113705.1799@sachi>

> On Mar 27, 2022, at 13:37, jdh <dhenman@gmail.com> wrote:
> Re: the phrase "parallel processing":
> So that beginners do not get the wrong idea I wish to make clear that Unix based systems are not designed to, and can not do parallel processing.  Strictly speaking it is also not designed to do real time processing. Unix/Linux does do multitasking by using task switching.  Unix based systems does allow users with the proper priviledge to set task priority, which helps in deciding which task gets more run time.

Well… drifting off the original topic: parallel processing, real time processing, and SMP are all somewhat orthogonal concepts from each other.

The original "parallel processing" systems ran a version of AT&T unix (e.g. Sequent).  It predated SMP.  Or I suppose you could say that IBM was doing parallel processing even before that.

“Real time” processing is requirements that responses to events fall within the manufacture’s specifications.  i.e. “all context switches are guaranteed to occur within 50ms”.  Then the designers of the end applications can work with those constraints and develop systems that meet the requirements of their end users.

SMP is about the very tight coupling between the CPUs.  Apple’s latest glossy keynote on the M1 Ultra gives a whiff of the problems that parallel processing introduces which SMP solves.

  parent reply	other threads:[~2022-03-28 13:48 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-27 18:37 jdh
2022-03-27 19:06 ` Bart Schaefer
2022-03-27 19:24   ` Ray Andrews
2022-03-28 13:47 ` Perry Smith [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-03-26  4:34 jdh
2022-03-25  4:34 Perry Smith
2022-03-25 18:27 ` Bart Schaefer
2022-03-26 18:10   ` Philippe Troin
2022-03-26 22:19     ` Bart Schaefer
2022-03-27 17:32       ` Philippe Troin
2022-03-27 17:42         ` Bart Schaefer
2022-03-27 19:23 ` Dominik Vogt
2022-03-28 13:26   ` Perry Smith
2022-03-28 13:31 ` Perry Smith

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