On Mon, Dec 22, 2014 at 09:20:28AM -0600, Robert Blair wrote:
> 
> Some experiments (ATLAS as a for instance) have decided to simply
> upgrade their SBCs to 64 bit capable rather than suffer through the
> various problems associated with trying to hang on to the old hardware.
>  We saw issues beyond just 32 bit vs. 64 bit.  The older systems were
> many generations back in terms of capability which caused numerous hard
> to diagnose problems.  In our case the pentium4 default broke some code
> since the SBCs we had were pentium3 only.  Most things worked but a few
> applications simply crashed.  The cost of upgrading was lower than the
> human cost of finding and fixing this sort of thing.
>

Ahem, we see no special problems with running SL6.6 on Pentium3 (1GHz, SDR RAM)
and 32-bit Athlon (DDR1 RAM) machines, even with low ram (0.5GB typical). Most
problems we do see are rooted in the old "laptop" chipsets used by these SBCs
that were never properly documented by Intel and properly supported by Linux.

But of course we do not run any full-featured applications (firefox, etc).

Upgrading to new hardware depends on the depth of your pockets of course,
but we also see technical problems - some new 2GHz+ 64-bit SBCs overwhelm
power supplies originally built to run 0.1GHz motorola 68020 SBCs. Also they are much
more sensitive to good air flow for cooling. Also we see a very high failure
rate of our chosen 64-bit VME SBC (vendor unnamed, suspect faulty PCBs or bad BGA soldering).

K.O.


> 
> On 12/18/2014 02:59 PM, Ian Murray wrote:
> > On 18/12/14 20:16, Konstantin Olchanski wrote:
> >> On Mon, Dec 15, 2014 at 04:51:19PM -0800, Keith Lofstrom wrote:
> >>> Again - the reason for 32 bit is not that I cherish old CPUs ...
> >>> And that is why I ask here; if anybody runs old machines for
> >>> compatibility reasons, it would be experimental scientists ...
> >>>
> >> On target you are.
> >>
> >> Us experimental scientists have embedded computers (VME form factor)
> >> with 32-bit CPUs and 0.5GB/1GB RAM. We run 32-bit SL4, SL5 and SL6
> >> on them today and I expect we will still be using these machines
> >> when SL6 becomes obsolete in 1-2-3 years. By then, I fully expect a 32-bit
> >> port of SL7/CentOS7 to become available, somehow.
> > Some talk of it here, with people having a first pass at it:-
> > 
> > http://www.karan.org/blog/2013/12/15/where-is-the-i686-in-rhel-7/
> > 
> > 
> >>
> >> But for today, I have not even digested the 64-bit SL7 yet, 32-bit SL7
> >> is not even on the wish list yet.
> >>
> >> Now, the ARM SL7 is a different matter. *that* I want yesterday.
> >>
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-- 
Konstantin Olchanski
Data Acquisition Systems: The Bytes Must Flow!
Email: olchansk-at-triumf-dot-ca
Snail mail: 4004 Wesbrook Mall, TRIUMF, Vancouver, B.C., V6T 2A3, Canada