Northstar Horizon - test-drb@ccmp.vtda.org

2 Nov 1999

I did some similar fooling around by populating an SRAM card with
battery-backed rams.  It wasn't worth it at the time, though.

I even have a 32K card with battery backup on board.  I also built a RAMDISK
with a battery backup so I could dump an entire SA1004 to it in one stroke
and keep it alive with a couple of motorcycle-battery sized gel cells and a
major DC-DC converter.  I built one for a business partner and hooked up
solar cells and one of those adjustable DC-DC converters (one of the old,
Old, OLD Boschert adjustable open-frame types) to bring the 60 Vdc or so
down to 14Volts and another to build the 5 Volts from that.

Dick

-----Original Message-----
From: Allison J Parent &lt;allisonp(a)world.std.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Tuesday, November 02, 1999 6:48 PM
Subject: Re: Northstar Horizon

...
 <Nowadays, it's really tempting to use an EPROM
or Battery-Backed SRAM to
<hold the entire CP/M CCP, BDOS, and BIOS, and let the warm boot reload the
<CCP from there.  That would certainly make the control-c quicker.

Nowadays!  I did this back in early 81 using 2732s.  I put a monitor, bios,
ZCPR2 and BDOS in that.  The CCP and BDOS only eats 5.5k.  It was set up
rather odd as the system runs from a small 2716 at cold boot with a monitor
and then by user command loads the 8k image into ram from IO addressed
"romdisk".  The CTRL-C was very fast as it could do INIR copies from the
rom.  A later version still running is 256k of eprom (27512s) had all of
cpm, loader, ASM, VEDIT, SID (and more).  This version the boot EEprom
is at 0000 and is truncated bdos, bios and a loader.  This was done so that
I could have it load  CPM.SYS image for testing from the selected drive
including the ROMDISK.  This is raw speed.

Allison