3 Sep
1999
3 Sep
'99
6:04 a.m.
After reading all the comments on CP/M computers a
comment was made that CP/M
is a faster OS that DOS.. I have found this to be very true.
My Kaypro 1X boots up in 5 seconds, and loads MBASIC in about another 5
seconds, also
executes the same BASIC code faster than on my XT.
Now on my old Compaq XT, it takes about 30 seconds
just for the hardware to
powerup,
then another 20 seconds to boot to a DOS prompt, then another 15 seconds to
boot BASIC.
So can some of the experts here tell me why CP/M is so
much faster ?
Well, you should skip the hardware power up time when compareing,
since most old systems didn'n check anything at all, so its
5+5 vs. 20+15. Now take the more sophisticated OS into account.
MS-DOS (I assume something like 2.11 or higher) is a _way_ more
complex system (loadable device driver etc.) while CP/M is just
a memory image with some adjustments. If you take DOS 1.x _without_
any additional stuff, the needed time to boot gets _very_ close.
Further on, CP/M is barely more than a programm loader, while MS-DOS
offers quite more abstraktion - in fact, the CP/M functionality
is more like the PC-BIOS (I still won't call MS-DOS an OS either).
Next the programm structure on file is a bit more complex than just
loading the image - additional processing is needed. And finaly,
the Coding is bigger - this results in way longer loading times,
since the media (Minidisks) are at the same transfer rate.
Oh, and last but not least: If you compare a Z80 4MHz to an 8088 4.77MHz,
you get a very close finish ... especialy when the programm isn't realy
adapted to the processors - and most of the early apps have just been
(more or less) automatic conversion of 8080 code.
Gruss
H.
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Ich denke, also bin ich, also gut
HRK