Difference VMS7.3-2 and 7.3

[Arch_Muthiah]

Hi,
I would like to build a application on Alpha DS10/OpenVMS 7.3-2. I contacted HP to get VMS 7.0 or 7.3 to use as a build sever. But they said that it is very difficult to get VMS 7.0. They suggested me to go for thrid party resellers to get that licenses.

I don't think any of our customers still using VMS 7.3-1 or earlier. Looks like all VMS customer already moved to VMS 7.3-2.

My question is that if I build our application on 7.3-2, will it have downwards compatiblity till VMS 7.0 or atleast 7.3?

Thanks
Archie

[Andy Bustamante]

Version 7.0 wasn't available for very long, you might still be able to come up with a 7.3 distribution, if you e-mail me I can provide a vendor.

If you build on 7.3-2, the app may or may not run on earlier versions. If your customer base is on 7.3-2 or better, you should use 7.3-2 as your build environment.


Andy

[Hoff · Accepted solution]

If you're approaching or at the "think" stage here, you might want to go and find out what version(s) your customer(s) are using; you'll want to know what versions are in use here, in order to make an appropriate choice, and in order to provide guidance to your customers.

If you're looking for upward-compatibility, you'll want to use a Prior Version Support release, probably OpenVMS V6.2 for this case. There are lists of PVS and current version support (CVS) releases around.

The oldest release that an AlphaServer DS10 will boot is OpenVMS Alpha V7.1-2 with ECOs, or V7.2-1 with ECOs, or a later release. The AlphaServer DS10 will not boot OpenVMS Alpha V7.0.

OpenVMS Alpha and OpenVMS I64 provide upward compatibility for user-mode code, and not downward or backward compatibility. There are any number of back-linking discussions around, and you'll end up reading those if you want to learn more about how to back-build. (This sequence is not supported, so you're going to have to figure out what works for your application.) It's reasonably likely that code built against V7.3-2 won't work on V7.3 -- not without a little extra work stashing RTLs and in the LINK command and options file(s) and some related care, and a test or three on the older release.

From my time in OpenVMS Engineering and my work since then, I'd not choose nor suggest V7.0 here. In the V7 range, I'd not suggest anything prior to V7.1-2 (with ECOs). And V7.3-2, and later, is a far better choice.

Some reading material on working toward downward/backward compatibility:
http://h71000.www7.hp.com/wizard/wiz_6829.html
http://h71000.www7.hp.com/wizard/wiz_7555.html
http://h71000.www7.hp.com/wizard/wiz_2932.html

Don't assume you can ship out the back-built code untested, either. Which then means you'll probably just build on the older release. If you want to discuss back-building, feel free to contact me offline. (I've done it, and have the scars to prove it...)

Stephen Hoffman
HoffmanLabs LLC

[Willem Grooters]

I have (had) to deal with building on higher versions than my customer, and the solution is fairly simple:

Compile your programs, and deliver the object files, a link procedure and related files, and, eventually, missing libraries and installation procedure. You can put all your objects into one or more object libraries and link from there, this may be more convenient in case of a large number of object files).

I've seen this working (and used it myself) when the application files were developed on 7.3-2 and delivered on 7.1-2. I cannot guarantee it will work in all cases, but it's worth a try.

HTH

Willem

[Steven Schweda]

I, too, would vote for V7.3-2 over earlier
versions. I've had success building some
all-C applications on V7.3-2 for a user at
V7.2, by defining __CRTL_VER appropriately.
You may find some useful info in:

SYS$LIBRARY:DECC$CRTL.README

[Arch_Muthiah]

Thanks Andy, Stewen, and Willem for your useful detals information. I will try to do as per Willem and Stewen suggestion.

And many thanks to Hoff for the detail information on this area. I know around 50 customers currently using 7.3-2, but this application has been sold to hundrads of customers, I have no list of them. As I doubt there may be customers who may come up with issues on their older version of VMS systems. Your information was very very useful. Now I am going to build on V7.3-2 only focusing the current customers.

When need I will certainly contact you all.

Archie