[comp.sys.ibm.pc] J8 slot

davej@entropy.UUCP (01/16/87)

Is the short slot (J8) next to the power supply on an IBM PC/XT
(640K motherboard) good for anything?  I have two short cards in
a system and neither will work in that slot.  Will anything work
in that slot?  I am wasting a long slot on a short card, and I
anticipate needing the long slot for another long card in the near
future?

Thanks for any words of wisdom.
-- 
Dave Jenner                     (206) 543-6182, 543-2888 (Message)
Department of Astronomy, FM-20  BITNET: davej@uwaphast
University of Washington        UUCP: ...!uw-beaver!uw-entropy!phastvax!davej
Seattle, WA 98195               INTERNET: davej@entropy.ms.washington.edu

ashok@softart.UUCP (01/18/87)

> 
> Is the short slot (J8) next to the power supply on an IBM PC/XT
> (640K motherboard) good for anything?  I have two short cards in
> a system and neither will work in that slot.  Will anything work
> in that slot?  I am wasting a long slot on a short card, and I
> anticipate needing the long slot for another long card in the near
> future?

The short slot on the XT was intended for a the IBM expansion box interface
card.  As such, it has an extra set of buffers between it and the data bus.
For cards to work in that slot, they **MUST** toggle a signal (B8-card selected)
.  It must be low when the processor is reading from that slot and high when
the processor is writing to that slot.

The previous explanation was if you are hardware oriented.  To answer the
original question...it is "good for anything".  The answer is YES!  The IBM
short async card will work in that slot if you install a jumper at location
J1.  This will enable that signal and cause the card to work.  Most short
cards will have some sort of a jumper to make that card work in that slot.
Check the user manual for the card.  Hope this helps.
> 
> Thanks for any words of wisdom.
> -- 
> Dave Jenner                     (206) 543-6182, 543-2888 (Message)
> Department of Astronomy, FM-20  BITNET: davej@uwaphast
> University of Washington        UUCP: ...!uw-beaver!uw-entropy!phastvax!davej
> Seattle, WA 98195               INTERNET: davej@entropy.ms.washington.edu

You are welcom.

------------------------
Ashok C. Patel
Softart Microsystems Inc.

kuo@skatter.UUCP (01/22/87)

In article <486@entropy.ms.washington.edu>, davej@entropy.ms.washington.edu (Dave Jenner) writes:
> 
> Is the short slot (J8) next to the power supply on an IBM PC/XT
> (640K motherboard) good for anything?  I have two short cards in
> a system and neither will work in that slot.  Will anything work
> in that slot?  I am wasting a long slot on a short card, and I
> anticipate needing the long slot for another long card in the near
> future?
> 
> Thanks for any words of wisdom.
> -- 
> Dave Jenner                     (206) 543-6182, 543-2888 (Message)
> Department of Astronomy, FM-20  BITNET: davej@uwaphast
> University of Washington        UUCP: ...!uw-beaver!uw-entropy!phastvax!davej
> Seattle, WA 98195               INTERNET: davej@entropy.ms.washington.edu

I have my diskette controller (short) card in that slot and it works
fine!


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