From: Gronblom, Ernest (Ernest.Gronblom@brooks-pri.com)
Date: Wed Sep 25 2002 - 14:18:53 EDT
Thanks to: Alan, Johan Brusche, Raul Sossa S., and of course Tom Blinn.
All confirmed my sanity that Tru64/Alpha AXP have always been 64 bit.
Someone here was asking how to determine if an Alpha had a 32 bit or 64
bit version installed. I told him that I was pretty sure that all Alphas
were 64 bit, but we also have Sun and HP systems in here which have H/W
that is only 32 bit compatible so you can install either 32 or 64 bit
versions of the OS. This was causing some confusion so I knew if I
asked here I would get a definitive answer. Thanks again and I love
this list!
More details from the responses, for those interested:
o File offsets are 64 bit integers (off_t), allowing files
considerably larger than 2 GB.
o In V5, I think AdvFS uses 64 bit integers for the block
counts of file systems.
o 64 bit pointers are used everywhere.
o Some individual subsystem may impose 32 bit limits
- - - - - - - - - - - -
As you thought correctly, Alpha's always have been straight 64-bit
machines. There's nothing in the operating system nor in the hardware
that limits you to 32 bits. Physically in the hardware however
I believe there are only 48 bits available to address physical memory
locations, but still you have a 64bit virtual address space.
The "Alpha Architecture Handbook" is at:
http://www.support.compaq.com/alpha-tools/documentation/current/alpha-archt/
alpha-architecture.pdf
- - - - - - - - - - - -
Tru64 UNIX is a native 64 bit operating system. There have been, along
the way, some subsystems that still had some 32 bit data fields, most of
them have been made "long" over time. The OS is NOT a 32 bit system in
any meaningful sense. If you have more specifics, I can probably get
you a more detailed answer (if you need it). And bear in mind that for
interoperability with other UNIX systems, some of which are 32 bit, we
do use some 32 bit constrained interfaces, both in the kernel and in
some layered components (commands and utilities).
-----Original Message-----
> Hello Admins,
>
> This is hopefully a quick question and after searching on the archives I
> wasn't able to find anyone else who asked this question, and forgive me
> if it sounds absurd, but:
>
> I have thought that Alpha's have been 64bit all along. I know that you
> can compile code in 32bit mode, but is there any hardware limitation
> that causes the OS to run in a 32 bit mode?
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
= Ernest Gronblom Brooks-PRI Automation -
- Sr. Unix Administrator =
= E-Mail: Ernest.Gronblom@brooks-pri.com -
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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