From: ben <bfranchuk(a)jetnet.ab.ca>
To: cctalk(a)classiccmp.org
Subject: [cctalk] Re: terminology [was: First Personal Computer]
The third thing is a real OS. Nobody has one, as a
personal computer.
CP/M and MSDOS does not handle IRQ's. Unix for the PDP-11 is real
operating system but not personal as it requires a admin,and a
swapping media.
This an auld refrain among *nix partisans of the ESR type, but I've yet
to hear someone offer up a real defense of it. Even putting aside what
"handles IRQs" means here (yes, strictly speaking the IRQs on the IBM
PC are handled by the BIOS and/or add-on drivers/utilties, but DOS most
certainly makes use of the facilities provided,) why does that make it
"not a real OS?" What does PDP-11 Unix provide which MS-DOS doesn't to
make one "real" and the other not?
Certainly, nothing about a single-tasking single-user text-based
environment *requires* interrupt-based I/O, even if it may smooth out
performance in some aspects. And there's little if any call for a
security system that'd require an administrator account in such a
model; if one user "owns" the machine, whatever they decide to do to it
can be Considered Legitimate. Virtual-memory capability may certainly
enable the user to do more than they'd otherwise be able to, but it's
hard to make an argument for it as a *requirement;* even *nix can run
without swap, and in point of fact DOS can be support virtual memory
with a protected-mode extender.
Or is it multi-tasking capability itself that makes the difference?
Can't see why that should be the case; it's definitely convenient, but
as one person can only be doing so much at any given time, it's also
hard to see that as a *requirement.*
So what, then, consitutes a Real Operating System, and why?