More on tape streamer in AT/286

[Gerard J van der Grinten PA0GRI]

Hello Folks,
Happy New Year to all.
In response on my inquiry for tape support for Microports SysV AT 2.4
the following is found.
I got a response from Bob -obiwan!bob- saying all goes well here but have
problems with Sony tapes. 
Then i got a response from Johannes -sgren at dynas.se- telling he had the same
problem I had when he had been thinking. Thinking was a bad idea.....
To get to the solution: I was using int2 (hardware line). That is in reality
int9 (second PIC). Now it seems Microport did a good job in screwing up
interrupt support. The second interrupt controller can only handle the disc
controller (int14) and any other service requested fails with no response.
Having both an (inteligent) excelan card and a (inteligent) tape controller
I was short on interrupts. (int7 for lp, int6 for floppy, int5 for excelan
int4 for 1 standard comm1, int3 for ast 4 port serial, and int2 unusable
due to braindamage at Uport. (adding a wire to int10 - int15 proved that
it does not work)). I had to give up another interrupt line and comm1 was
the one getting shot. I removed the interrupt wire (jumper) but left the
port in for satisfaction of the BOOTROM. (it plugs vectors needed).
Then i moved the interrupt for the ast card to 4 and the tape to int3.
That is a working configuration. The int4 MUST be the first comm interrupt
otherwise IT DOES NOT WORK. It is surely a pitty that the second PIC is
unusable for extensions. 
Another hint: tar uses /dev/mt/0m as a major/minor for its default device.
Normaly it is linked to /dev/rdsk/fd but if you relink to /dev/rmt0 it
goes default to the tape drive.
I hope You gain some information of this lesson for your situation if you
ever get to it.
An other question: Are there archives for Microport (messages and / or
programs) besides the dead Microport bbs. (was not updated anymore for a year)
Regards, gerard.