gpg: failed to create temporary file '/var/lib/lurker/.#lk0x573c7100.hantslug.org.uk.8147': Permission denied
gpg: keyblock resource '/var/lib/lurker/pubring.gpg': Permission denied
gpg: Signature made Thu Nov 22 20:25:56 2007 GMT
gpg: using DSA key 20ACB3BE515C238D
gpg: Can't check signature: No public key
On Thu, Nov 22, 2007 at 08:10:14PM +0000, Adam Trickett wrote:
> On Thursday 22 Nov 2007, Sean Gibbins wrote:
> > Rob Malpass wrote:
> > > Brilliant ;-] Thanks Al
> > >
> > > This prompts two more related questions:
> > > 1) I tried a 64 bit ubuntu version on my Sempron box last summer but
> > > couldn't really detect any major speed benefits - presume even now
> > > this will only be visible in certain (presumably maths intensive)
> > > applications?
> >
> > Correct.
>
> 64-bit CPUS can address more memory and address it more easily, so if you had
> 64Gb of RAM on your box in 64-bit life would be easy, in 32-bit mode it gets
> complicated. As most of us at most have at a maximum of only 4Gb it's not
> something to worry about much. AMD claim that their processors are mildly
> faster in 64-bit mode as it's cleaner than the legacy Intel 32-bit mode, but
> you'd hardly notice.
Actually, due to some of the awkwardnesses of the 32-bit x86
architecture, you start seeing issues and difficulties with 32-bit
machines handling more than 1GiB of RAM(*). Given the new Vistas of
opportunity opening up for the hardware manufacturers, new machines
will start pushing these limits quite quickly. Get used to 64 bit now,
before you absolutely have to. :)
Hugo.
(*) Below about 940MiB, 32-bit x86 is perfectly happy. Up to 3-4GiB,
you need a different memory model in the kernel, which slows things
down a little. Above 4GiB, you need yet _another_ memory model, which
in theory will go up to 64GiB, but in practice gets harder and harder
to manage as you increase the RAM(**). Current Athlon64 machines, in
64-bit mode, will handle up to 16TiB of RAM (44 bits of addressing
space), if you can find a box that will take that much. :)
(**) Someone on linux-kernel this week claimed that anyone running
more than 12GiB of RAM on 32-bit x86 needed their head testing. As you
increase the RAM, the amount of space needed to manage that RAM also
increases, and the whole thing gets out of hand quite fast.
--
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
--- 2 + 2 = 5, for sufficiently large values of 2. ---
