MFM/RLL Disk Driver for ISC or ESIX?

[James Tsillas]

In article <16938 at darkstar.ucsc.edu> daniel at cis.ucsc.edu (Daniel
Edelson) writes:

   The problem is that it's virtually impossible to find an MFM/RLL
   controller that can use a secondary IRQ. They all seem to be
   hardwired for 14 (or is it 15,) unlike the ESDI controllers which
   are often jumper selectable. One way around it is to mess with the
   second controllers edge connector, but this is kind of messy. If
   anybody knows of an MFM/RLL controller that is jumper selectable to
   IRQ 15, would they care to post that information?

I believe the Adaptec RLL controller is configurable for IRQ15. I managed
to "adapt" my WD RLL using the above mentioned surgery. I can make the 
suggestion that if you do this. Do NOT use the on board BIOS rotines to
format: these routines are not aware that the IRQ has changed and will
format you primary! Also, disable the BIOS and set the I/O port to the
secondary address. The following posting gives some additional info:

> 
> Hello, a friend of mine forwarded me a news posting
> in which you indicate that you got a WD1006 to interrupt
> on IRQ 15. Can you please tell me how you did this?
> 
> Thanks,
> Daniel Edelson
> daniel at cis.ucsc.edu
> 
> 

Very easy.  All I did was a little surgery on the card.  What you have
to do is to cut the trace on the 7th finger of the 16 bit extension on
the solder side of the card.  (see enclosed figure).  Scrape off a
little of the covering over the upper portion of the trace so you can
solder a small wire to it.  IRQ 15 is the connection that is 1 finger
to the front of the finger you just cut.  All I did was on my mother
board the sockets had room for the connectors to expand and I inserted
the small wire there.  When the card is inserted the contact pinches
the wire between it and the side of the connector.

-----|-------------------------------------------------------------------------
 B   |									       |
 R   |									       |
 A   |									       |
 C   |									       |
 E   |									       |
     |									       |
     |									       |
     |									       |
     |									       |
     |									       |
     |									       |
     |									       |
     |									       |
     |-------|                             |---| | | | | | | | | | | | | |------
     |       |                             |   | | | | | | | | | | | | | |
     |       |-----------------------------|   |--------------------------
                                                           ^ IRQ 15
                                                             ^ IRQ 14

The sketch is rough at best.  Just remember to work on the SOLDER side
of the card (components down) and be carefule with the solder gun.

Jim

*** Please note that I make no warranties of any kind about doing this.
    All I can say is that it works for me.
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