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Re: Breaking /emul/ia32-linux for squeeze

md@Linux.IT writes:

> On Mar 16, Simon Richter <sjr@debian.org> wrote:
>> Well, it would get i386/amd64 in line with sparc/sparc64, powerpc/powerpc64
>> and s390/s390x. That would allow us to get rid of a lot of specianl cases,
>> including the hack for libc6-386.
> I think it would be very helpful if somebody could summarize why a
> multiarch system is useful, except for the obvious case of installing
> proprietary i386 software on amd64 systems.

People who use those systems frequently could probably provide more
cases, but I know of three cases beyond running "qualified" or
"supported" 32-bit binaries on 64-bit systems):

- On platforms where the 32-bit mode is not so register-poor as i386,
  using 32-bit binaries can be significantly faster and less
  cache-disruptive than 64-bit binaries because they need less memory
  bandwidth.  Even on amd64 systems, some executables have this trait.

- Some users have code that does not function properly on systems with
  sizeof(int) != sizeof(void*).  Multiarch gives them a chance to
  migrate this code at their own pace.

- For environments with certain configuration management or regulatory
  requirements, qualifying new binaries is a considerable cost --
  having nothing to do with whether the software is "proprietary" --
  and multiarch makes it easier for them also to migrate at a pace
  that makes sense to them.

Michael Poole

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