7 Dec
2007
7 Dec
'07
2:51 a.m.
On Thu, 6 Dec 2007, Tony Duell wrote:
I am probablty being unfair, but I find all the 9000
series after the
9000/200 to be 'boring unix boxes'. Lots of HP custom silicon (some, I
believe have PA-RISC CPUs, the ones that are 68K-based have other HP
custom chips in them). The 9000/200 series hae a few PALs in them, but
they are mostly stadnard chips. And there are some interesting add-on boards
for them, admittedly those can often be used in the 9000/300 series too.
You are unfair, just have a look at the 9000/840 (1986/87). We have one
(still running 24/7), together with a 7978 and several 7935 drives (the
system's running from SCSI disks though). The interesting parts of this
machine:
1. It's the first PA-RISC machine
2. It's completely TTL (SN74xx, PROMs and memories)
3. The CPU consists of about half a dozen PCBs
4. It's useful as a bridge between the HP-IB world and the UNIX/Internet
world
As an example, the ALU resides on the EU (execution unit) board and is
built from SN74AS181 (eight of them for 32 bits). Another example: the ECC
controller on the memory controller board is a (rarely found) SN74ALS632,
IIRC. The other CPU boards are the CA (cache), TL (table lookaside) and
IU (instruction unit).
The only custom chips are found on the I/O interfaces (bus interface IC
for the CIO) and the FPU boards (the FPU consists of two ICs embedded into
a plethora of TTL ICs).
BTW many I/O boards have intelligent subsystems on them, e.g. the terminal
MUX board is a Z80 system with SIOs etc., the ethernet board has a
MC68000 (as many ethernet boards at that time), and the HP-IB board has
a HP 1TL1 IC (is there a datasheet available?).
I wish I had a *real* service manual/schematics for this machine...
Christian