Tandem NonStop TXP

The Tandem NonStop TXP was a new, faster implementation of the TNS architecture for large online transaction-processing installations. A wider microcode store, cache memory and more direct extended addressing raised performance substantially while retaining compatibility with established Guardian applications.

TXP systems scaled from two to sixteen processors and could be linked by the FOX fibre-optic interconnect. Multiple systems could therefore operate as a much larger fault-tolerant network without abandoning Tandem’s distributed process and storage model.

Notable Features

• The TXP delivered about 2 MIPS per processor, more than twice the performance of NonStop II.
• It introduced cache memory and a redesigned four-board processor using TTL and programmable-array logic.
• FOX fibre links connected multiple NonStop II and TXP systems into campus-scale clusters.

Historical Significance

• TXP proved that Tandem could increase performance while preserving the software investment of its earliest customers.
• Its clustering and networking capabilities supported very large banking, reservation and financial-processing installations.

Collector’s Notes

• Processor, memory and storage capacity varied from small paired systems to large multi-cabinet installations.
• Original FOX interfaces and matched redundant controller hardware are important parts of a representative configuration.

Specifications

Technical Information
Name	Tandem NonStop TXP
Manufacturer	Tandem Computers
Launched	Tuesday, November 1, 1983
Discontinued	Late 1980s
Country	United States
CPU	Tandem proprietary TXP processor
Units Sold
Power	Redundant, serviceable system power supplies; requirements depended on cabinet configuration
Fault Tolerance	Lock-step checking within modules, process pairs, dual paths, mirrored disks and online expansion
Architecture	Cached TNS stack architecture with improved extended addressing
Networking	Expand networking, X.25, SNA and FOX cluster links
Operating System	Guardian 90 / Guardian 90XF
Expansion / I/O	Dual Dynabus; optional FOX fibre-optic links between complete systems
Keyboard	External operator console terminal keyboard
Storage	Mirrored fixed disks and tape subsystems with redundant controllers and paths
Sound	No general-purpose sound hardware
Graphics	Terminal-oriented text output; no integrated graphics subsystem
Display	External operator console terminal; no integrated display
ROM	Boot, diagnostic and processor microcode storage; capacity varied by generation and configuration
RAM	Typically 2MB to 16MB per processor; system capacity varied
CPU Speed	83.3 ns processor cycle; approximately 2 MIPS per processor