Re: A Customer's Request For Open Source Software

[Kilgallen@SpamCop.net (Larry Kilgallen)]

In article <3F4EA616.30607@attbi.com>, "Robert I. Eachus" <rieachus@attbi.com> writes:

> The point though, is that you don't open a file and read it record by 
> record or line by line.  You map a segment into your process and can 
> address any bit in the segment at random.

> This was the paradox of Multics that most people never understood.  The 
> system could afford to have good security because compared to 
> conventional OSes security checks--and all of the other overhead of 
> accessing a file--only needed to be done maybe one-thousandth as often, 
> if that.

That sounds true for unrestricted access, but the number of occasions
for checks should have to be the same as any other operating system for
data protected as "single writer at a time".