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Groups > comp.os.linux.advocacy > #108174

Re: Why does Linux need memory management units and cache?

From Grant Edwards <invalid@invalid.invalid>
Newsgroups comp.os.linux.advocacy, comp.os.linux.embedded, uk.comp.os.linux
Subject Re: Why does Linux need memory management units and cache?
Date 2012-05-20 14:42 +0000
Organization PANIX Public Access Internet and UNIX, NYC
Message-ID <jpavsc$6q2$1@reader1.panix.com> (permalink)
References <exMtr.167357$JQ.57569@fx02.am4> <a1q0nqFjl3U1@mid.individual.net> <2RQtr.477893$y11.316125@fx21.am4>

Cross-posted to 3 groups.

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On 2012-05-19, 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> wrote:
> Niklas Holsti wrote:
>
>> On 12-05-19 15:40 , 7 wrote:
>>> Why does Linux need memory management units and cache?
>>> ------------------------------------------------------
>>>
>>> Excuse us, this is bothering me much.
>>>
>>> Why does Linux need memory management units
>> 
>> To implement virtual address spaces for processes.
>
> Virtual address space in a nut shell means program counter relative
> operation.

No, that's not what virtual address space means.

>> Linux doesn't need cache, logically. But Linux systems usually need
>> lots of memory, more than can be provided on chip, and access to
>> off-chip memories is usually so slow that a cache makes the system
>> much faster.
>
> So a cache could be implemented in software.

Not really, no.

> And if done properly with a fast program, it should run faster and
> better than hardware

Nope.

> which would use up a lot more software in setting up and managing a
> cache.

-- 
Grant

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Thread

Why does Linux need memory management units and cache? 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> - 2012-05-19 13:40 +0100
  Why does Linux need memory management units and cache? Kulin <remailer@reece.net.au> - 2012-05-19 14:26 +0000
  Re: Why does Linux need memory management units and cache? Niklas Holsti <niklas.holsti@tidorum.invalid> - 2012-05-19 19:40 +0300
    Re: Why does Linux need memory management units and cache? 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> - 2012-05-19 18:34 +0100
      Re: Why does Linux need memory management units and cache? Piergiorgio Sartor <piergiorgio.sartor.this.should.not.be.used@nexgo.REMOVETHIS.de> - 2012-05-19 19:44 +0200
        Re: Why does Linux need memory management units and cache? 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> - 2012-05-19 19:57 +0100
          Re: Why does Linux need memory management units and cache? Piergiorgio Sartor <piergiorgio.sartor.this.should.not.be.used@nexgo.REMOVETHIS.de> - 2012-05-19 21:17 +0200
            Re: Why does Linux need memory management units and cache? 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> - 2012-05-20 22:53 +0100
      Re: Why does Linux need memory management units and cache? Grant Edwards <invalid@invalid.invalid> - 2012-05-20 14:42 +0000
        Re: Why does Linux need memory management units and cache? Hadron<hadronquark@gmail.com> - 2012-05-20 16:48 +0200
          Re: Why does Linux need memory management units and cache? Nix <nix-razor-pit@esperi.org.uk> - 2012-05-20 22:19 +0100
            Re: Why does Linux need memory management units and cache? 7 <email_at_www_at_enemygadgets_dot_com@enemygadgets.com> - 2012-05-20 22:55 +0100
              Re: Why does Linux need memory management units and cache? Nix <nix-razor-pit@esperi.org.uk> - 2012-05-21 16:24 +0100
                Re: Why does Linux need memory management units and cache? chrisv <chrisv@nospam.invalid> - 2012-05-21 10:44 -0500
                Re: Why does Linux need memory management units and cache? GreyCloud <mist@cumulus.com> - 2012-05-21 10:51 -0600
                Re: Why does Linux need memory management units and cache? GreyCloud <mist@cumulus.com> - 2012-05-21 10:51 -0600
                Re: Why does Linux need memory management units and cache? Foster <frankfoster50@yahoo.com> - 2012-05-21 12:53 -0400

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