> To the extent that user_prefs files and (most) command-line options
> are similarly backwards- and forwards-compatible, this upgrade will
> be painless for us. To be more explicit, I would like to make
> necessary changes *before* the upgrade to the extent that I can, in
> such a way that the system will behave as expected both before and
> after the upgrade.
>
> What I'm trying to determine here is to what extent that's possible,
> and conversely to what extent I will have to synchronize various
> parts of the upgrade procedure.
My impression is that *probably* you can put the 3.0 syntax into user_prefs
files while running 2.6x, and things will probably still work. You will get
lint errors, but I don't *think* they will abort processing. Likewise the
2.6x values will cause lint errors in 3.0. But again, I *think* they will
not abort processing.
I would insure a blank line on each side of a line that is changing between
2.x and 3.0. I've occasionally had what appear to be scanner recovery
problems after an error, and the blank line gives the scanner a better
chance of correct recovery.
OTOH, I think you will have problems with command line arguments, unless you
clean out the depreciated things before attempting the upgrade. Since
presumably only depreciated things were actually removed in 3.0, there
should have either been a viable alternative in 2.6x that is still valid in
3.0, or the items should have been useless in 2.6x.
In either case, I think you should probably be able to get the command lines
up to 3.0 spec while still on 2.6x, IF they did it right. If not, you may
need to come up with some very clever script code to decide which line to
used based on the program version.
Loren
