North Star Horizon

From: Allison J Parent <allisonp_at_world.std.com>
Date: Tue Feb 24 20:58:46 1998

<I did some software work on a Horizon many years ago. As I recall, it ha
<two full height 5.25" bays, a good sized power supply behind the bays (o
<the right side) and a shorty S-100 card cage on the left, 8 card slots?
<the NS motherboard also had some logic on the motherboard, at the rear.
<believe there were one or two 8251 serial ports, a baud rate generator,
<maybe a parallel port or interrupt controller (look for an Intel 8214 or
<28-pin AMD IC)?

Err no. The back plane will have two 8251 serial port and a parallel port
and supporting ttl for same. It has a heartbeat timer for that can drive
interrupts. The interrupt logic is on the CPU ZPB-A and it allows 1-of-8
RST locations to be used (z80 mode 0). there isn't a 8214 in the whole
thing if it's a Horizon unless the board with it is not from NS*!

BTW, 112 slots though a full 64k system could be configured in as few as
three cards! The lineup would be CPU, 64k ram card, disk controller and
the IO already built into the mother board(2 serial and 1 parallel).

The power supply is responsable for 30% of the total weight and is
electrically robust.

It was easy to check, mine is sitting here cranking a z80 asm file.

Allison
Received on Tue Feb 24 1998 - 20:58:46 GMT