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

3 Nov 1999

Well, I don't know what instructions were used to move the SA1004 contents
to the BBRAMDISK, but it didn't take long to write in MBASIC and compile
with BASCOM.  It was pretty similar to the formatter, since that was written
the same way.  The odd thing was, since I wrote a lot of assembler back
then, the ASM version of that program, or of the formater, for that matter,
was not noticeably faster than the BASCOM version.  Both were probably being
held up by the drive.  Nowadays, the 8MB ramdisk would be dirt simple, using
one simm and one CPLD, and a small one at that.

There was, by the way, an outfit nearby, which produced, among other things,
a 10MB RAMDRIVE for the TI-PC.  That product was interfaced via SCSI and was
moveable between systems.  It must have lived on a battery as well.

Dick

-----Original Message-----
From: allisonp(a)world.std.com &lt;allisonp(a)world.std.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Wednesday, November 03, 1999 6:53 AM
Subject: Re: Northstar Horizon

...
 > 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. 
At the time I did the RomDisk I also did a ramdisk (io port addressable)
not unlike the Compupro Mdrive.  the difference was I used Mixmos static
ram and used 4 AA (500mah) nicads to keep it alive for up to 100hours.
Total ram was 128k.  A later design used 2kx8 EEPROM and Cmos static rams
for 128k for each "drive".

I also have two BPK72 bubble memories (128kb each).

My current project is a dual semiconductor disk for S100 use 1mb or
flashram and 8mb of Dram battery backed up.  Both addressable Via port
addresses (uses otir/inir to read write blocks).  With current 1mb 30 pin
simms and FPGAs it's not a dense board.  I used 1mb 30 pin as I can get
then for near nothing.  Whats nice wth that config is I can preload it
and then plug it into another system and read/write it easily.

Allison