L
List Management Account
I have heard that before, "properly" is a really strong word in this case. Process priority is NOT enough in this case since even the highest priority processes "dies" for short periods
in my case I can literaly hear this since my sound card produces a quite distorted sound if it is not feed in time, and the process priority is set really high. This is probably a bad combination with my current network card being a really slow one. I would think at least one of the processors would be availiable to serve this high priority program even when the CD spins up but obviously not.
The major point is, there is a lot of "properly" things everywhere in a computer. I have heard from some place (It may be an evil rumor)
that microsofts own drivers (especially ATAPI) breaks the rules set by microsoft themselve for writing such a driver.
A properly set up NT system is probably good enough for controlling the question is: how do you know if it is set up properly and really
whitstand the disturbances. How do you do the swame thing with a PLC?
I would say it is easier to be reasonably sure a PLC works undisturbed than a computer with NT, especially if you really want to take any
advantage of the richer set of features on the computer. This does definitely NOT mean one is better than the other for all cases.
The original topic for this thread was not PLC v.s. computer but UNIX v.s. NT. My guess is that the average UNIX installation withstand
disturbances better than the average NT installation. This guess is not based on my own experience however. One basic difference between UNIX and NT that may affect this is the security philosophy: UNIX is closed but can be opended up if the administrator wants that, NT is open but
can be closed up if the administrator wants that. In UNIX can things the administrator thought people need be done, in NT can things the
administrator thought people dont need not be done.
You will ALWAYS find a particular installation of one of the systems to be better than another installation of the other, regardless of what system you want to proof beeing better.
/Johan Bengtsson
----------------------------------------
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
----------------------------------------
-----Original Message-----
From: Vladimir Bunyakin [SMTP:MIME :[email protected]]
> ------- Forwarded message follows -------
> From: [email protected]
>
> I would say that it heavily depends on what you mean by "disturbed".
...
> Another example (from my computer here at work). Every time I insert a
> CD, or the system thinks I may be trying to access the CD (like when
> changing directory and NT wants to know the name of the CD on order to
> display it). Sometimes almost everything in my computer stops for about
> 4-5 seconds while the driver spins up the CD and reads the needed
> information. I have understood this as a driver issue (ATAPI) (I don't
> really bother enough to do something about it, but if the computer would
> have been controlling something then...)
...then nothing unusual would happen. If the controlling part of software is properly designed and process priorities are properly assigned, inserting a CD in a tray and spinning it up definitely cannot bring any significant delays to the control programs.
in my case I can literaly hear this since my sound card produces a quite distorted sound if it is not feed in time, and the process priority is set really high. This is probably a bad combination with my current network card being a really slow one. I would think at least one of the processors would be availiable to serve this high priority program even when the CD spins up but obviously not.
The major point is, there is a lot of "properly" things everywhere in a computer. I have heard from some place (It may be an evil rumor)
that microsofts own drivers (especially ATAPI) breaks the rules set by microsoft themselve for writing such a driver.
A properly set up NT system is probably good enough for controlling the question is: how do you know if it is set up properly and really
whitstand the disturbances. How do you do the swame thing with a PLC?
I would say it is easier to be reasonably sure a PLC works undisturbed than a computer with NT, especially if you really want to take any
advantage of the richer set of features on the computer. This does definitely NOT mean one is better than the other for all cases.
The original topic for this thread was not PLC v.s. computer but UNIX v.s. NT. My guess is that the average UNIX installation withstand
disturbances better than the average NT installation. This guess is not based on my own experience however. One basic difference between UNIX and NT that may affect this is the security philosophy: UNIX is closed but can be opended up if the administrator wants that, NT is open but
can be closed up if the administrator wants that. In UNIX can things the administrator thought people need be done, in NT can things the
administrator thought people dont need not be done.
You will ALWAYS find a particular installation of one of the systems to be better than another installation of the other, regardless of what system you want to proof beeing better.
/Johan Bengtsson
----------------------------------------
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
----------------------------------------
-----Original Message-----
From: Vladimir Bunyakin [SMTP:MIME :[email protected]]
> ------- Forwarded message follows -------
> From: [email protected]
>
> I would say that it heavily depends on what you mean by "disturbed".
...
> Another example (from my computer here at work). Every time I insert a
> CD, or the system thinks I may be trying to access the CD (like when
> changing directory and NT wants to know the name of the CD on order to
> display it). Sometimes almost everything in my computer stops for about
> 4-5 seconds while the driver spins up the CD and reads the needed
> information. I have understood this as a driver issue (ATAPI) (I don't
> really bother enough to do something about it, but if the computer would
> have been controlling something then...)
...then nothing unusual would happen. If the controlling part of software is properly designed and process priorities are properly assigned, inserting a CD in a tray and spinning it up definitely cannot bring any significant delays to the control programs.
