Mailinglist Archive: opensuse (686 mails)

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Re: [opensuse] 64 bit vs 32 bit RAM consumption
  • From: Per Jessen <per@xxxxxxxxxxxx>
  • Date: Wed, 31 Jul 2013 14:29:11 +0200
  • Message-id: <ktavv1$han$1@saturn.local.net>
Carlos E. R. wrote:

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El 2013-07-23 a las 12:08 -0400, Cristian Rodríguez escribió:

It uses 64 bit pointers which require twice as much space, so yeah it
is likely that some programs will use a lot more ram.

I forgot pointers.

Doesn't code use short or relative pointers?

No, not compiler generated code.

There is something called "x32 abi" , which is an x86_64
implementation with 32 bit pointers, so far, no distribution has been
released officially using this ABI model.

I don't know in Linux, but in MsDos you could choose the model of your
code,

Linux uses the flat memory model:

http://en.wikipedia.org/wiki/Flat_memory_model

and there were several possibilities of code size, data size,
etc. Pointers could be absolute or relative. The segment register
could be fixed and play with normal registers only (in theory the

DOS ran in real mode, Linux runs in protected mode. In protected mode,
you have access to the full 32bit address space, and the segment
registers are more or less disabled, except FS and GS.


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