12 Feb
2003
12 Feb
'03
6:05 a.m.
> > I like the 186 myself but have to admit
that the time for segmented
> > memory has passed, in general purpose computing.
> Well, define general purpose computing. In my
eyes this describes real
> computers ... ala IBMish Mainframes, and Segmented memory never had a
> place there. When going for small systems, the 186 is still one of the
> best CPUs to use. Powerfull, fast, simple and high integrated. I don't
> know anything which can't be done in a megabyte of mem.
How about a database record sort on a field with a
data length greater
than 1MB?
First of all what kind of ill designed database this is?
Ok, don't answer. If that's your goal, I'd do it like any
other operation, read the fields to compare in chunks of
max say 64K (well in reality i'd use the block/cluster
size of the drive) and compare it. Chances are pretty
good that they will be already different in the first
block, and disk access time is here more relevant than
comparsion speed (which is done in one machine instruction,
at the spped of the data bus). Even if your CPU is be
able to handle megabyte size fields in one chunk, the
incremental compare will outperform... As so often
algorythm wins over brute force.
Gruss
H.
(I did several 100k of 80186 assembly :)
--
VCF Europa 4.0 am 03./04. Mai 2003 in Muenchen
http://www.vcfe.org/