Looking for cassete basic rom code

jim stephens jwsmail at jwsss.com
Mon Mar 20 11:55:25 CDT 2017

On 3/19/2017 9:47 AM, Adam Sampson via cctalk wrote:
> <snip>
> http://www.minuszerodegrees.net/bios/bios.htm
If anyone knows who owns the site, I have a small smidge for the 
reference page about
Jumper 18 on the AT 5170 motherboard.

It is set to make the motherboard memory decoder drop out half of the 
512K from decoding as memory
as well as disabling the memory if there is any.

you put this option in to do the disable when you install the AT/370 
card.  It has 256K on board
which fills in the other 256 K.  When the 370 is running there is no 
difference in the operation of
any software, as the dual ported memory is just memory to the AT. If you 
have a 256K AT this
is a rare and exotic memory expansion board for all intents an purposes.

The hosting software handles  the dual memory as it needs.

When the hosting software is running, and you have an IBM 3270 card 
which is compatible with the
regular 3270 remote access software, you can either run that software 
and have a CUA connection
over the 3270 coax to the mainframe, or a DFT session if you have that 

If you have the AT/370 software running there is a function key action 
which switches between a
3270 CUA session with your mainframe, which if you want it to be very 
useful should be VM of some
sort (we has VM/SP5) running.  With that session running you can file 
share with the mainframe's
minidisks, initiate IND$FILE uploads and downloads from elsewhere 
(similar to FTP for the most part),
and have a CUA VM session logged in.

You can flip the PC to a CP / CMS session on your local 370 PC system as 
well.  It sees both the local
disk 30mb (unless you finagle the host software, about the limit), or 
you can map mainframe
minidisks to your local VM, which is the real payoff.

And there is a DOS session running in the smige off memory left, so you 
can copy files to / from
the 30mb local AT disk (pretty much all you got room to run).

And you can set up the printer port on the AT to be a legitimate 3270 
printer if you have the
mainframe 3270 port config generated to have a printer there.

Would love to archive the entire site, it seems to have a lot of great 
well organized information.

Anyway at length someone might want to put the purpose of J18 (or one 
use of it) in that page.

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