Re: How to develop a random number generation device

On Sun, 16 Sep 2007 11:11:25 -0700, MooseFET <kensmith@xxxxxxxxx>
wrote:

On Sep 15, 10:59 am, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
[...]
Windows is a "big OS" in that thousands of modules make up the actual
priviliged runtime mess. A "small OS" would have a very tight, maybe a
few thousand lines of code, kernal that was in charge of memory
management and scheduling, and absolutely controlled the priviliges of
lower-level tasks, including the visible user interface, drivers, and
the file systems.

I'm not sure that I would call "file systems" controlling part of the
Kernal's job. I would step that out one layer. It really would be a
task that is given its time and access privilages by the kernal. By
splitting the two, you would make it easier to design and debug both.
Once you have, one file system controlling software going, You could
run a second one, being debugged, controlling different media.


That's what I meant; the file system, and user GUIs and such, are just
more jobs, not part of the kernal at all. VMS worked that way. File
systems were loadable tasks, not part of the os proper. RSTS had
multiple "runtime systems", API sets essentially, which is what the
user tasks saw; some emulated other OS's.

Drivers are an intermediate case. They can be dynamically loadable,
but must have hardware access and, directly or via DMA, can access all
of memory.

John


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