From: b259phl@utarlg.uta.edu (PHILIP LIPPEL)
Subject: Re: info needed on realtime data collection
News-Software: VAX/VMS VNEWS 1.41    
Organization: The University of Texas at Arlington
Date: Fri, 22 Jan 1993 18:10:00 GMT

In article <93022.090839SXC3@psuvm.psu.edu>, <SXC3@psuvm.psu.edu> writes...
>We are thinking of using OS2 in our lab to make better use of our computers,
>since we use them for running the equipment and analyzing data.  However, the
>FAQ states that, under OS2, real time data collection may be compromised.
>Could someone explain how tweaking the OS2 DOS settings fixes this? Or are
>there other folk who use OS2 in a lab setting who can tell me how they work
>around this?  It's no use changing operating systems if it messes up our data,
>though I must admit the multitasking ability is very tempting.
>                 Thanks for your time,
>                         Sabrina Chase
>                         Penn State Physics Dept.
>                         sxc3@psuvm.psu.edu
Since OS/2 handles all interrupt services itself (emulating them for DOS
programs as required) it has to be a little bit slower than a DOS machine
directly handling the interrupts. It is impossible to know whether or not this
will affect your data acquisition efforts without knowing 
1) What your data acquisition rates are, and your acq hardware
2) What kind of machine (or at least, what processor type and speed) you 
  are using. 

I can, however, give you a few examples of acquisition setups I have used 
succesfully.

A 386/16 sx machine with 6Meg of memory running a mass spectrometer with
windows- based software (running under Win-OS2, of course). This is not a
very demanding application in that most of the "intelligence" is in the 
MS hardware. The MS electronics communicates with the PC through a serial
port.
This runs fine, and the PC is useful for word processing, network communications,
etc. These other apps are slow (it's a pretty low-power machine!) but the data-
taking never misses a step.

386/16 and 386/33 machines with Scientific Solutions Labmaster Data Acquisition
boards installed. (These are general purpose D/A, ditgital i/o , and 100 Mhz
A/D cards). The slower machine has been used to run data acq software for 
a tunneling microscope-- this is DOS software. No problems at up to a few hun-
dred points per second- hasn't been tested beyond that due to limitations of
the microscope and our present samples. Since this is a full-screen DOS session,
we don't do anything else simultaneously. We're working on OS/2 device drivers 
for this board and an OS/2 version of the software.
The second Labmaster card is being used primarily for digital i/o from a 2-dimen
sional position-sensitive detector. Expected data rate is up to 100k events
/second. Each even requires a sixteen bit data transfer. All parts of this
system are " under development". Eventually the data taker will be a 486/33,
but we have transferred data at 100kHz on the 486/33 using a preliminary, 
DOS-based, program running in a DOS window. 

Our experience so far: Interrupt emulation is excellent; we haven't had any
 problems with DOS software. 
Philip Lippel
Physics Dept.
UT Arlington
phl@sgiris.uta.edu

Newsgroups: comp.os.os2.misc