topic Re: Processor Information for OpenVMS Alpha 8.2 in Operating System - OpenVMS

Processor Information for OpenVMS Alpha 8.2

Manesh Sasankan — Tue, 17 Apr 2007 01:54:27 GMT

i want to know whether OpenVMS Alphaserver 1000 4/266 running OpenVMS V8.2 is 32-bit or 64-bit RISC architecture.

is there any command to find this out. i have a application which was supported in OpenVMS Alpha V7.3-2. now i tried the same application in OpenVMS 8.2 & it looks like working. but is there any other constraint or short-comings for doing this.

Appreciate if you could comment on this!!

Re: Processor Information for OpenVMS Alpha 8.2

Steven Schweda — Tue, 17 Apr 2007 02:03:36 GMT

All Alphas are 64-bit. A newer version of
VMS will not change that.

> is there any other constraint or
> short-comings for doing this.

Do you really want someone who has not seen
your program to tell you if it will work
correctly on VMS V8.2? Ok. Of course it
will work correctly. What could go wrong?

Have you thought about running some tests?

Re: Processor Information for OpenVMS Alpha 8.2

Manesh Sasankan — Tue, 17 Apr 2007 02:12:26 GMT

Thanks for the reply steven.

Normally 64-bit architecture is backward compatible to 32-bit applications( exceptions may be there). and i think this the issue that i face now. i haven't run any test, but there may be a chance that it would fail for some certain test right!!!

thanks,
Manesh

Re: Processor Information for OpenVMS Alpha 8.2

Steven Schweda — Tue, 17 Apr 2007 02:19:31 GMT

OpenVMS Alpha V7.3-2 is as much 64-bit as
OpenVMS Alpha V8.2 is. What kind of
32-bit/64-bit differences do you fear?

Whenever the OS changes, whether it's a patch
or an upgrade, or the installation of some
other new product, it's possible that an
application will be affected. In this case,
it's not very likely.

Re: Processor Information for OpenVMS Alpha 8.2

Kris Clippeleyr — Tue, 17 Apr 2007 02:20:43 GMT

Hi,
Well-written, well-behaved user mode programs that were developed on an older release of OpenVMS rarely cause trouble on newer releases.
OTOH, if you have written kernel mode code, or used undocumented features, I suggest you recompile and relink on the newer version of OpenVMS and perform some serious testing.
Btw, normal, well-written, well-behaved user programs tend to be 32-bit (still).
Regards,
Kris (aka Qkcl)

Re: Processor Information for OpenVMS Alpha 8.2

Manesh Sasankan — Tue, 17 Apr 2007 02:27:01 GMT

Thanks for ur replies. I'm quite new to this VMS stuffs!! thats y I'm asking such queries which may look awkward !! :)

actually i was in a assumption that OpenVMS 7.3-1 & 7.3-2 had 32-bit architecture and the newer 8.2 had 64-bit architecture. thats y i raised this as a concern. i didn't know that the entire OpenVMS Alpha machine are 64-bit..

thanks to everyone.

Re: Processor Information for OpenVMS Alpha 8.2

Steven Schweda — Tue, 17 Apr 2007 02:36:03 GMT

> [...] normal, well-written, well-behaved
> user programs tend to be 32-bit (still).

That's a little over-simple. It depends on
what you mean by "32-bit". For a C program:

CC /POINTER_SIZE affects some things.

Various "#pragma" directives affect some
things.

The macro "_LARGEFILE" affects some things.

The programmer can affect almost anything.

> i didn't know that the entire OpenVMS Alpha
> machine are 64-bit..

That much is certainly true. It's also true
that moving a program to an _older_ version
of VMS may cause problems if it uses new VMS
features. Moving a program to a newer VMS
version is usually pretty safe, depending on
exactly what the program does.

Re: Processor Information for OpenVMS Alpha 8.2

Robert V Dixon — Tue, 17 Apr 2007 06:50:57 GMT

Best if you run some tests, but as an aside, introduced by your posting, OpenVMS itself is not the determining factor and for your concern about 32-bit or 64-bit, I suspect that the move from 7.3 to 8.2 is not the actual issue.

Summarily:
VAX/[Open]VMS is 32 bit for all VAX,
alpha/OpenVMS is 64 bit for all alpha.

Re: Processor Information for OpenVMS Alpha 8.2

Ian Miller. — Tue, 17 Apr 2007 08:14:10 GMT

alphaservers have always been 64 bit. OpenVMS Alpha introduced features to take advantage of the 64 bit addressing from V7.0 and continues to do so.

Re: Processor Information for OpenVMS Alpha 8.2

Robert Gezelter — Tue, 17 Apr 2007 08:48:16 GMT

Manesh,

First things first. All Alpha processors are 64-bit RISC.

The Alphaserver 1000 that was referenced uses an EV4 processor. There are some improvements in later generation chips, but they these improvements are not incompatible with code generated for earlier generations of chips.

In general, non-privileged programs should run on later releases without problems.

- Bob Gezelter, http://www.rlgsc.com

Re: Processor Information for OpenVMS Alpha 8.2

Sebastian Bazley — Wed, 18 Apr 2007 06:18:23 GMT

As to upwards compatibility on VMS:

We used to use this utility on VAX/VMS 5.x where it was originally compiled and linked (in 1994).

The executable (only) was copied to Alpha/VMS 1.x and VESTed (NOT recompiled), and it still works on Alpha/VMS 7.3-2.

It would probably perform better if it was recompiled and relinked on Alpha, but as we now rarely use it we have not bothered.

Re: Processor Information for OpenVMS Alpha 8.2

Martin Hughes — Wed, 18 Apr 2007 07:07:11 GMT

Can I ask why you are testing the application on 8.2? if you are planning on upgrading then you might want to consider the latest version - 8.3.