> On May 9, 21:34, Dom Sweetman wrote:
> >o Workstations/computers from SGI and their "friends" Pyramid and
> > Siemens-Nixdorf. All big-endian, probably not adaptable. SGI's
> > success means that this is much the largest group of machines.
> I believe Larry McVoy mentioned in passing (on the sparc list) that SGI
> *could* do LE (or 'that other byte order' as he said :-) if necessary,
> although he certainly didn't mean bi-endian I think.
Yes, Andreas pointed that out too - and now I remember that SGI were
going to provide Windows/NT as an alternative OS, or on really
hallucinated days as a *replacement OS*.
> I have lots of software that I have carefully written (or made sure
> others have written) in a way portable enough to let me compile it
> without problems under Linux. I nfs-mount the whole disk with
> hundreds of megs of code and start the build, and it works fine.
> The problem comes when I execute the code: I want to share the data
> too, and I can't do that today without writing code to painfully
> byteswap field by field inside all the structs.. and I know this is
> a real pain to do, because I have already written the code for it
> for the (relatively small) part of the data which is sent out of the
> system (must be VAX-readable).
The C standard doesn't allow you to assume that the memory image of
data structures is portable between compilers, let alone between
architectures. Endianness is one problem - but so are different
numeric representations, size of data types and alignment rules.
For most purposes it's better to export/import data in 'printable
text' forms; but if this is really too slow then there are tools like
Sun's XDR. [Do you remember XDR, invented somewhere in the early-mid
80's? it had tools which would auto-generate modules to dump/load
arbitrary C data structures to a file-like stream of bytes. And it
went with a remote-call thing too.]
But if the $10M-per-year project which upgrades Word for Windows can't
afford to do anything other than brain-dump binary data, it seems a
bit unkind to expect unpaid volunteers to do so...
Dominic Sweetman phone: +44 171 700 3301
Algorithmics Ltd home: +44 171 226 0032
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