[unios] Re: Generic Design

[Pieter Dumon]

From: Pieter Dumon <Pieter.Dumon@rug.ac.be>

Some more comments on the real content of your document. 
I won't comment on the principles, allthough I'm not convinced.

> Hardware
> --------
> ...
> There are exceptions to the rule that hardware is objects. One is storage,
> which isn't used in the same way, and should be protected from being used
> up in some other way. 
 
Do you recon that storage is a big part of the devices in a computer?

>CPUs aren't objects either. Objects shouldn't deal
> with the CPU(s) at all. Their only worry is to get enough processing time,
> which is handled as concrete things that can be possessed. Realtime
> processes get a real value, whilst usual processes get a percentage of the
> availible processing power.

If you would try to implement such a schedulign algorithm, it would kill
you system. Just work with multiple priority queues. Real-time processes
and drivers get high, static priority, normal processes get a dynamic, low
priotity. Dynamic means it is changed by the way the process behaves: 
if the process uses up the time quantum that is assigned to it, its
priority decreases, if it yields control to the system before it's time is
used up, it's priority increases. Lower priority queues get a longer
time quantum.  In this way, interactive processes, i.e. processes that do
I/O or regularily wait for some event, get a higher priority but can
execute shorter. cpu-intensive processes get a lower priority but can hold
the cpu longer. This is roughly algorithm used in all OSs. Why? Just
because it closely resembles the mathematically best scheduling algorithm.
 
> Processing power is delegated down the system
> tree. The root owns all time. Each user maybe owns an equal percentage of
> the time. The users may then give their respective time shares to processes
> as they like. The same method could be used for all kinds of storage.
> Otherwise I can't think of any hardware device that shouldn't be an object.

This would really hurt the system! Users who only run one command-line 
UI don't need much power !!!!

Pieter
 
----------------------------------------
 Pieter.Dumon@rug.ac.be               
                                      
 http://studwww.rug.ac.be/~pdumon     
 
 ICQ  : 12428974
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