"Gene Wirchenko" wrote

| I was at a Mac meeting on Monday. Someone described doing just
| that but with a machine that was about nine years old. It was a
| high-end laptop at the time it came out which might have softened the
| difficulty, but nine years.
|

But isn't that very much the exception? My
understanding is that Apple only supports 2
versions back, which is basically 2 years back.
And their fan base don't mind because most
of them want an excuse to buy new stuff.
The vast majority of software on Windows still
supports XP, now 17 years old.

| Microsoft's XP Mode system does not work properly on my Windows 7
| Professional system despite multiple tries. And it does not work --
| by design -- on my laptop which has Windows 7 Home. This is not
| backwards compatibility; it is backward combatability.
|

Yes. I haven't tried to use it but I'd guess
it's really more of a slight wrapper than an
actual compatibility mode. I remember debates
about that when Vista came out. The API
function GetVersionEx can be called to find out
what Windows version your software is running
on. But with Vista it started lying. For
"compatibility". If the software was run in compa
t mode GetVersionEx would return the compat
version! But lying to the software, of course,
doesn't cure anything. It just makes the
software look bad.
I had to write my own function to find the
real version. Then if my software was running
on Vista/7 and I hadn't yet updated it to support
those versions, I'd have it quit with a message.
The other option was to accept Microsoft's new
rules and have my software be untested at best
and malfunctioning at worst.

In other words, the compat mode didn't provide
XP compatibility. It just provided a slight wrapper
to make Vista/7 seem like XP by doing things
like lying with GetVersionEx and transparently
rerouting operations with folders that had moved.

I don't know all the details. I just made sure
none of my software would work until I'd got
around to updating and testing.