Chapter 4 PA-RISC Computer Systems - OpenPA.net

Stratus Continuum
4.53 Stratus Continuum
4.53.1 Overview
Stratus Technologies 240 built a line of “Ultra High Availability Fault Tolerant” PA-RISC (32-bit PA-
7100 and 64-bit PA-8x00) based servers called Continuum (with a stated availability of 99.999% and
more). These systems feature a great deal of redundancy, peaking in having four CPUs to form one
single logical processor. The PA-RISC-powered systems were phased out in 2004 in favor of Intel
IA32-based systems (not covered here).
The Stratus Continuum servers ran either Stratus-modified HP-UX 11.00, Stratus VOS (PA-RISC support
from release 13.0 until 14.7.2) or FTX, Stratus’ own Unix System V Release 4 multiprocessor OS
(however support differed between the 400 and 600/1200 lines).
4.53.2 Hardware Details
I/O
The Continuum 600 and 1200 series are basically the same system, except for the chassis configuration.
The 600 has six slots for the main bus (called the Golf bus), and the rest of the space is filled with I/O
card cages meant for secondary I/O boards. The 1200 has twelve slots for the main bus which occupies
the entire width of the chassis. Secondary I/O boards go into a separate chassis. Both models have
space for two rows of cooling fans on the top, and two rows of disk drives on the bottom (and also
either a QIC or DAT tape drive or CDROM drive). The redundant power supplies with built-in UPS
resides at the very bottom.
The main Golf bus is the main interconnect between the “big” boards. It is also redundant and selfchecking.
The “big” boards consist of the following (all these are FRUs):
� G7xx - CPU and memory boards (of different number and type of processors, speeds and memory
sizes)
� K450 - 4-channel HVD fast wide SCSI and Ethernet adapter
� K460 - 4-channel HVD fast wide SCSI and Ethernet adapter
� K470 - A “carrier board” that can contain up to three PMC (PCI-mezzanine) daughter cards
� K600 - Adapter to two PK-buses which connects to the secondary I/O card cages
On the 600 chassis, the six slots consists of two for the pair or CPU/memory boards, and four more
slots for two pairs of “big” boards. On the 1200 chassis, there are slots for two pairs of CPU/memory
boards and four pairs of big boards.
In addition the 600/1200 main chassis also has a pair of Console Controller cards which provides the
RS232 console terminal and RSN modem connectivity. This controller also has a command mode that
allows the operator to type commands on the console to reset the system, power down, power up, etc.
It runs on “housekeeping power” that is independent of the rest of the system. The Console controller
also contains some environmental monitoring circuitry that checks the chassis internal temperature and
will increase the cooling fan speed if necessary (the fans themselves are also hot-swappable FRUs).
The secondary I/O chassis can be used to plug in a wide array of I/O boards (all Stratus proprietary).
These boards are also used on the XA/R line. FTX supported many of the communications boards
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