From: tmcreek@eos.ncsu.edu (TOBIN MATTHEW CREEK)
Subject: Re: COM3/4 problem.
Originator: tmcreek@c00477-224wi.eos.ncsu.edu
Reply-To: tmcreek@eos.ncsu.edu (TOBIN MATTHEW CREEK)
Organization: North Carolina State University, Project Eos
Date: Mon, 27 Jul 1992 13:06:36 GMT


In article <0095E31B.3C8BBA20@FHYDRA.FYSEL.UNIT.NO>, dahls@fhydra.dnet.unit.no (Joern Yngve Dahl-Stamnes) writes:
>Thus spoke the keyboard of tmcreek@eos.ncsu.edu (TOBIN MATTHEW CREEK):
>>
>>In article <1992Jul26.210238.21921@mksol.dseg.ti.com>, mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes:
>>>In <0095E0C5.50EBD660@FHYDRA.FYSEL.UNIT.NO> dahls@fhydra.dnet.unit.no (Joern Yngve Dahl-Stamnes) writes:
>>Not true again.  You can have 2 COM ports on the same interrupt, you just can't
>>use them both at the same time.  I.E., com1 and com3 cannot work at the same 
>>time.  Make sure you put your mouse on a free interrupt if you want to use it
>>with another COM port.
>
>What does that exactly mean? Does it mean that if I'm using the mouse on COM1:
>and I'm running a program that read data from COM3:, the mouse will interfear
>if I move it while the program read data from COM3:? Can I use the mouse
>*after* the read operation on COM3: is done?

Yes, in a word.  I had my mouse on com1 and my modem on com3 for a VERY short
time.  Ever try to do downloads from Crosstalk for Windows and move the mouse
at the same time?  The mouse will not respond until the download is finished.

>>	You may want to get a program called 34instal.  It will 
>>get com3 and com4 recognized under DOS.  This may fix the problem with the 
>>diagnostic.  34instal can be found on 128.252.135.4 under /systems/ibmpc/msdos/
>>sysutl, I think.
>>
>>>>Have I done anything wrong since the diag. program won't accept the extra COM
>>>>ports? Everything on the machine seems to work just fine. The mouse work
>>>>(connected to COM1:) and the external modem on COM2: work just fine.
>>>
>>>>COM1: and COM3: will both have IRQ4 and COM2: and COM4: will both have
>>>>IRQ3, while LPT1: have IRQ7. Will this work?
>>>
>>>No, this won't work.  You can't simultaneously access devices which
>>>have the same IRQ on an ISA card.  If your machine is MCA, I take it
>>>all back.
>>
>>This is true.
>
>When you write MCA, is this a brand name, ie. like Olivetti, IBM etc., or is it
>a type of machine (sorry to ask this silly question, but I just have to be
>shure - if you are talking of the brand name MCA, we are not familliary with it
>here in Norway)?

MCA is IBM's creation.  It is short for Micro Channel Architecture.  It is a 
replacement for ISA expansion slots (Industry Standard Arch.)  EISA is 
the next step above ISA.  It is available on 486's now.  It can share IRQ's,
but I've heard this is only possible with a specially written driver.
MCA machines are expensive, and the boards are outrageous (a SoundBlaster
Non-Pro is US$100 for ISA and US$400 for MCA).  MCA can be found on IBM Model
50's and above.

>Thanx to all who have replied.
>
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+
>* I went back to my mother,           * Joern Yngve Dahl-Stamnes           *
>* I said, "I'm crazy ma, help me!"    * University of Trondheim            *
>* She said, "I know how it feels son, * The Norwegian Institute of Tech.   *
>* 'cause it runs in the family."      * Division of Physical Electronics   *
>*       - The Who, Quadrophenia       * e-mail: dahls@fhydra.dnet.unit.no  *
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+
>
Newsgroups: comp.os.ms-windows.setup