decompilation as archiving?

[Chuck Guzis]

> On Thu, 30 Nov 2006, Richard wrote:
> 
> Has anyone considered decompilation (producing sources from
> binaries) as a way of archiving system or application software that is
> defunct?

It depends.  I've disassembled plenty of ROMs in my day and it's not 
too bad--just time consuming.   Decompilation can be somewhat harder 
if you don't know the way the original compiler worked.  Aggressive 
automatic optimization can really obscure the original code, 
especially when the optimizer can move code or schedule instruction 
issue times.  A lot of the time, an optimization will result in a bit 
of clever code that not many programmers would consider writing, if 
they were working in assembly.  On the other hand, compilers organize 
data and code in a predictable way, which does give you a leg up over 
a hunk of code generated from assembly.

That being said, the occasional orphan application or operating 
system will yield its secrets only to decompilation/disassembly.  
Depending upon how littlel you understand the original program and 
its structure and optimization, the time required can be large.

For modern processors, I own a copy of IDA Pro, probably one of the 
best (and wouldn't you know that it comes out of Russia!).

The only worrisome nugget is that if you're in the USA, decompilation 
may be a violation of the DMCA--I'm not sure.

Cheers,
Chuck