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From: Ben Greenfield via TUHS <tuhs@minnie.tuhs.org>
To: Tuhs <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] CMU Mach sources?
Date: Wed, 26 Jun 2019 15:32:32 -0400	[thread overview]
Message-ID: <04827B96-5B5E-473E-A95F-67C4292B69D1@cogs.com> (raw)
In-Reply-To: <34DB62C2-7D8C-468B-99E1-CA035C9141A2@eschatologist.net>




> On Jun 26, 2019, at 3:22 PM, Chris Hanson <cmhanson@eschatologist.net> wrote:
> 
> One thing to remember about Mach is that it really was a *research* project. Some of the things that have been complained about, e.g. “pointless” or “needless” abstraction and layering, were done specifically to examine the effects of having those layers of abstraction. Does their presence enable different approaches to problems?

I’m surprised the study of Mach needs any justification.
Mach certainly happened and is certainly enjoys a large and growing installed base.
I’m bothered that some feel the need to belittle the interests of others.

I would be more impressed if those criticizing weren’t so hand-wavy and had more specific points….




> Do they enable new features altogether? What’s given up by having them? And so on.
> 
> Just as an example, a lot of the complexity in the Mach VM system comes from the idea that it could provide a substrate for all sorts of different types of systems, and it could have all sorts of different mechanisms underneath supporting it. This means that Mach’s creators got to do things like try dedicated network virtual memory, purpose-specific pagers, compressing pagers, etc. You may not need as much flexibility in a non-research system.
> 
> For another example, Mach did a lot of extra work around things like processor sets that wouldn’t be needed on (say) a dual-CPU shared-cache uniform-memory systems, but turns out to be important when dealing with things like systems with a hierarchy of CPUs, caches, and memories. Did they know about all the possible needs for that before they started?
> 
> Having met some of them, the people who created and worked on Mach were passionate about exploring the space of operating system architecture and worked to create a system that would be a good vehicle for that. That wasn’t their only goal—they were also part of the group creating what was at the time CMU’s next-generation academic computing environment—but the sum of their goals generally led to a very pragmatic approach to making things possible to try while also shipping.
> 
>  -- Chris
> 


  reply	other threads:[~2019-06-26 19:42 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-23  4:38 Chris Hanson
2019-06-23  5:15 ` Larry McVoy
2019-06-23  8:52   ` Andrew Warkentin
2019-06-23 13:39   ` Jon Forrest
2019-06-23 13:59     ` arnold
2019-06-23 14:03     ` Jason Stevens
2019-06-23  8:04 ` Jason Stevens
2019-06-23 14:54   ` Henry Bent
2019-06-23 21:52     ` Clem Cole
2019-06-25  0:06       ` Larry McVoy
2019-06-25  0:31         ` Theodore Ts'o
2019-06-25  0:45           ` Larry McVoy
2019-06-25  0:55             ` Kurt H Maier
2019-06-25  4:18               ` Larry McVoy
2019-06-26 23:19                 ` [TUHS] Craft vs Research (Re: " Bakul Shah
2019-06-27  0:16                   ` tuhs
2019-06-27 17:06                     ` Clem Cole
2019-06-25  1:00             ` [TUHS] " Richard Salz
2019-06-25  8:00               ` Kevin Bowling
2019-06-25 12:11                 ` Arthur Krewat
2019-06-25 12:17                   ` Arthur Krewat
2019-06-26  2:45               ` Kurt H Maier
2019-06-26  2:56                 ` Larry McVoy
2019-06-26 15:11                   ` Theodore Ts'o
2019-06-26 17:44                     ` Larry McVoy
2019-06-26 18:01                       ` arnold
2019-06-26 18:18                         ` Warner Losh
2019-06-26 19:22                       ` Chris Hanson
2019-06-26 19:32                         ` Ben Greenfield via TUHS [this message]
2019-06-26 20:21                           ` Larry McVoy
2019-06-27  0:22                             ` Chris Hanson
2019-06-27  1:02                               ` Larry McVoy
2019-06-27  1:26                                 ` Chris Hanson
2019-06-27  4:01                             ` Lyndon Nerenberg
2019-06-27 10:34                               ` Ben Greenfield via TUHS
2019-06-27 10:59                                 ` arnold
2019-06-27 11:13                                   ` Ben Greenfield via TUHS
2019-06-27 11:39                                     ` arnold
2019-06-27 14:58                                     ` Warner Losh
2019-06-27 17:25                                       ` Larry McVoy
2019-06-26 19:30                       ` Dennis Boone
2019-06-26 19:25                     ` Adam Thornton
2019-06-23  8:27 ` Kevin Bowling
2019-06-25  3:07 ` Gregg Levine
2019-06-25  8:15   ` Kevin Bowling
2019-06-25 18:18   ` Chris Hanson
2019-06-25 20:23     ` Gregg Levine
2019-06-26  1:04       ` Jason Stevens
2019-06-26  0:53     ` Jason Stevens
2019-06-25  7:49 ` Jason Stevens
2019-06-25  7:59   ` Andreas Grapentin
2019-06-23 22:08 Noel Chiappa
2019-06-23 23:54 ` Theodore Ts'o
2019-06-24 17:04   ` Jason Stevens
2019-07-01 13:20 Jason Stevens

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