Date   : Sun, 24 Jul 2011 15:36:15 +0100 (BST)
From   : tommowalker@... (Tom Walker)
Subject: Risc PC (Was 'Minitel in France')

> Eh? Acorn was *built* on backwards compatibility. OSFILE 5 will read
> a file's information on everything from a BBC Model A to a BeagleBoard.

Try to run some actual software on these machines, rather than just API 
tests. The amount of software that broke on every stage of Arthur > RISC
OS 2 > RISC OS 3 > RISC OS 3.5 > RISC OS 3.7 > RISC OS 4 (just to keep to
the Acorn developed ones) is unbelievable.

Acorn's attitude to backwards compatibility seems similar to yours, and seems
to fail to take into account that programmers aren't perfect, and the kind
of mistakes that break software between OS versions are incredibly easy to make. 

And there's no tolerance at all - for example, the previously mentioned 
SWI "OS_UpdateMEMC", 64, 64. The only thing this call can do on a RISC OS 
3 machine is crash it. So why is it allowed to? It could easily be trapped 
and silently ignored, and then all the software that used it would still
work on RISC OS 3. Instead Acorn allowed all that software to break and forced
the user to obtain updates or simply buy new software. And that's just one
example.

Somehow having to bin half your software when upgrading doesn't seem like
successful backwards compatibility to me.

Tom