Fwd: Is Robert a Deterministic System?

[Roger Critchlow-2]

---------- Forwarded message ----------
From: Nicholas Thompson <[hidden email]>
Date: Nov 29, 2005 10:17 AM
Subject: Re: [FRIAM] Is Robert a Deterministic System?
To: Roger Critchlow <rec at elf.org>


Thanks, Roger.  That is great.  So computers, like the rest of us, are
subject to the fallacy of induction.

But further, at the risk of being TOTALLY otiose, I am still not quite sure
how the measurement of activity gets transformed into a measure of
performance.  I think I could guess at it from what you said, but I would
love to have you spell it out for me.

I have to take Penny to the doctor now, so wont answer till this evening.

This has been wonderful, everybody.

I am very grateful.

Nick

Nicholas Thompson
nickthompson at earthlink.net
http://home.earthlink.net/~nickthompson


> [Original Message]
> From: Roger Critchlow <rec at elf.org>
> To: <nickthompson at earthlink.net>; The Friday Morning Applied Complexity
Coffee Group <Friam at redfish.com>
> Date: 11/29/2005 11:56:20 AM
> Subject: Re: [FRIAM] Is Robert a Deterministic System?
>
> On 11/29/05, Nicholas Thompson <nickthompson at earthlink.net> wrote:
>
> >
> > So, I still want to know.... I didnt get where I am today without
asking the

> > same stupid question over and over again -- when you ask your cpu howzit
> > performing, what actually gets measured?
> >
>
> Your computer has a list of processes to run.  Some of these are
> system services and some are user processes.  If you type ctrl-alt-del
> on Windows, you'll get the Windows Task Manager (assuming your
> computer isn't currently locked up) and under the Processes tab you'll
> get the list of processes.
>
> Under the column labelled CPU you get the percent of the CPU time
> which each process is using.  Click on the column label a few times
> and you'll get the list of processes sorted in descending order of CPU
> usage.  The list will resort itself every second or two as the usages
> change.
>
> Most of the processes are using 0% of the CPU.  This is because
> they're sleeping, waiting for user input or for a service request from
> elsewhere.  When the event they're waiting on occurs, they will wake
> up, service the event, consume some CPU cycles, and then go back to
> sleep.
>
> Near the top of the CPU usage sorted list there will be a process with
> the Image Name of "System Idle Process".  This is a process which does
> nothing.  It gets scheduled to run whenever there's nothing else to
> do.  It's currently consuming about 80-90% of the CPU time on my
> computer, so my computer is running a 10-20% capacity load.
>
> How does the computer know this?  There's another process near the top
> of the list with the Image Name "taskmgr.exe".  It's running 0-5% of
> the CPU on my machine.  This process is reading the list of processes
> to run and deciding which process to run next.  When it schedules a
> process to run it notes that the process was allocated a time slice.
> When the running process yields the CPU, either by going to sleep
> waiting for an event or because its time slice finished, the taskmgr
> will note how much of the time slice was actually used. Add up all the
> time slices used over a second and you get 100% of the CPU usage, less
> the context switch and interrupt service overhead.  So the computer
> doesn't know what it's doing, but it knows what it did over the last
> 1000 time slices and gives you a statistical summary of that activity.
>
> That's the first order story.  The second order story gets into
> allocating memory for the process, filling the memory with the right
> bits so the process can run its program on its data, and saving the
> memory bits back to more permanent storage.  This happens at several
> levels, each of which has pathologies.
>
> -- rec --

[Robert Holmes-2]

And that brings us full circle back to people. Your question "how the
measurement of activity gets transformed into a measure of performance"
reminds me of the time-and-motion studies popular in the early days of
management science. This might be an easy enough correlation to make if you
work on a production line or if you are a bricklayer, less so if your
working day consists of staring into the middle-distance and thinking.

Maybe we should just stick with computers... so much more quantifiable :-)

Robert

P.S. I've just learned from Wikipedia that Gilbreth - one of the proponents
of time & motion studies - defined 17 basic hand motions (called therbligs)
for bricklayers. He was able to reduce the number of hand motions used in
laying a brick from 17 therbligs to 5. Hooray for modernism.



On 11/29/05, Roger Critchlow <rec at elf.org> wrote:

>
> ---------- Forwarded message ----------
> From: Nicholas Thompson <nickthompson at earthlink.net>
> Date: Nov 29, 2005 10:17 AM
> Subject: Re: [FRIAM] Is Robert a Deterministic System?
> To: Roger Critchlow <rec at elf.org>
>
>
> Thanks, Roger.  That is great.  So computers, like the rest of us, are
> subject to the fallacy of induction.
>
> But further, at the risk of being TOTALLY otiose, I am still not quite
> sure
> how the measurement of activity gets transformed into a measure of
> performance.  I think I could guess at it from what you said, but I would
> love to have you spell it out for me.
>
> I have to take Penny to the doctor now, so wont answer till this evening.
>
> This has been wonderful, everybody.
>
> I am very grateful.
>
> Nick
>
> Nicholas Thompson
> nickthompson at earthlink.net
> http://home.earthlink.net/~nickthompson
>
>
> > [Original Message]
> > From: Roger Critchlow <rec at elf.org>
> > To: <nickthompson at earthlink.net>; The Friday Morning Applied Complexity
> Coffee Group <Friam at redfish.com>
> > Date: 11/29/2005 11:56:20 AM
> > Subject: Re: [FRIAM] Is Robert a Deterministic System?
> >
> > On 11/29/05, Nicholas Thompson <nickthompson at earthlink.net> wrote:
> >
> > >
> > > So, I still want to know.... I didnt get where I am today without
> asking the
> > > same stupid question over and over again -- when you ask your cpu
> howzit
> > > performing, what actually gets measured?
> > >
> >
> > Your computer has a list of processes to run.  Some of these are
> > system services and some are user processes.  If you type ctrl-alt-del
> > on Windows, you'll get the Windows Task Manager (assuming your
> > computer isn't currently locked up) and under the Processes tab you'll
> > get the list of processes.
> >
> > Under the column labelled CPU you get the percent of the CPU time
> > which each process is using.  Click on the column label a few times
> > and you'll get the list of processes sorted in descending order of CPU
> > usage.  The list will resort itself every second or two as the usages
> > change.
> >
> > Most of the processes are using 0% of the CPU.  This is because
> > they're sleeping, waiting for user input or for a service request from
> > elsewhere.  When the event they're waiting on occurs, they will wake
> > up, service the event, consume some CPU cycles, and then go back to
> > sleep.
> >
> > Near the top of the CPU usage sorted list there will be a process with
> > the Image Name of "System Idle Process".  This is a process which does
> > nothing.  It gets scheduled to run whenever there's nothing else to
> > do.  It's currently consuming about 80-90% of the CPU time on my
> > computer, so my computer is running a 10-20% capacity load.
> >
> > How does the computer know this?  There's another process near the top
> > of the list with the Image Name "taskmgr.exe".  It's running 0-5% of
> > the CPU on my machine.  This process is reading the list of processes
> > to run and deciding which process to run next.  When it schedules a
> > process to run it notes that the process was allocated a time slice.
> > When the running process yields the CPU, either by going to sleep
> > waiting for an event or because its time slice finished, the taskmgr
> > will note how much of the time slice was actually used. Add up all the
> > time slices used over a second and you get 100% of the CPU usage, less
> > the context switch and interrupt service overhead.  So the computer
> > doesn't know what it's doing, but it knows what it did over the last
> > 1000 time slices and gives you a statistical summary of that activity.
> >
> > That's the first order story.  The second order story gets into
> > allocating memory for the process, filling the memory with the right
> > bits so the process can run its program on its data, and saving the
> > memory bits back to more permanent storage.  This happens at several
> > levels, each of which has pathologies.
> >
> > -- rec --
>
> ============================================================
> FRIAM Applied Complexity Group listserv
> Meets Fridays 9a-11:30 at Mission Cafe
> lectures, archives, unsubscribe, maps at http://www.friam.org
>

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