Re: Retrieving JPG and GIF file data in an AS/400 program

From: John Hall <jhall@hillmgt.com>
> Bob Crothers wrote:
> > Little/Big Endian refers to the byte ordering.
> > In the AS/400 world (Aka: Big Endian), integer data is stored with the
high
> > order bytes first and low order bytes last.  As you would expect.
> >
> > In the Intel (and others) world, they use little endian.  Eg: the LOW
order
> > bytes come first followed by the high order bytes...in reverse order than
> > you would expect.
> > Why is this done?  Beats me.  Has something to do with the hardware level
> > and efficiency.  I just know this is the way the world is.
> >
>
> I believe this can be traced back to the original 8 bit processors for
> intel.  The first one I worked on was an 8008.  It was all direct coding
> in octal.  As I recall to process two numbers you had to load the low
> order bytes first and then use the carry flag on the high order bytes.
> So the little endian order made more sense.  All the intel processors
> after that kept the same byte order (Z80, 8080, 8088, 8086, 80286,
> etc.).

John, it goes way further back to the PDP-11 of 1969, and for the
same reason you mention (adding up low-order first).



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