No RISC No Fun

Mainframes: Convex SPP1000, SPP1200 & SPP1600

10 October 2008

The Convex Exemplar SPP1x00, introduced between 1994-1996, are scalable 32-bit mainframes, with either PA-7100 (SPP1000) or PA-7200 (SPP1200 and SPP1600) processors. They consist of three distinct system building concepts: the CD compact systems with up to 16 CPUs, the XA eXtended Architecture hypernodes with up to eight CPUs and the XA clusters, consisting of up to 16 linked XA hypernodes, with up to 128 CPUs.

HP started a collaboration with Convex in the mainframe sphere in the early 1990s with these PA-RISC based systems; Convex was later completely bought by HP (in the mid-1990s) and the SPP Exemplar computers integrated into HP’s own HP 9000 portfolio (first the joint-marketed S-Class and X-Class, later the HP V-Class).

The SPP 1x00 mainframes laid the foundation of the Exemplar crossbar architecture, with the 32-bit systems all using the same system design as the original SPP1000. The crossbar design was revised and improved in the 64-bit SPP2000 and later taken over into HP’s own V-Class system, basically only slighly faster SPP2000 systems. The first implementations of the Exemplar crossbar used rare Gallium arsenide gate arrays (GaAs) chips.

Mainframes: HP/Convex SPP2000 (S-Class/X-Class)

10 October 2008

The jointly marketed Exemplar SPP2000 (Convex)/S-Class and X-Class (HP) are the 64-bit Exemplar successors to the 32-bit based SPP1x00s from the mid-1990s. The SPP2000 are the direct predecessors of the HP 9000 V-Class systems (which were then sold only from HP after the complete acquisition of Convex. They feature a similar but slightly modified crossbar architecture, upgraded with 64-bit PA-8x00 processors. Single nodes can carry more processors (16), more RAM (32GB) and have a different I/O system (PCI) than their predecessors; the clustering ability has been increased twofold — SPP2000 clusters (called X-Class by HP) can be built from up to 32 interconnected SPP2000 nodes (S-Classes at HP).

In contrast to the SPP1x00 line of Exemplars, the compact CD models — two closely coupled nodes and no SCI clustering attachments — were dropped with the SPP2000 and only the concept of a single node and multiple nodes as cluster retained. Also changed was the SCI (CTI) clustering topology — in contrast to the four unidirectional rings (2.4GB/s overall) of the SPP1x00s, clustered SPP2000s form a torus with each of a single node’s eight memory controllers attaching to two SCI rings.