Several years ago we posted an unusual MCM that’s purpose was a mystery. It was clearly made by IBM and clearly high end. While researching another mystery IBM MCM both of their identities came to light. The original MCM is an emulation processor from a Cadence Palladium Emulator/Accelerator system.
In the 1990’s IBM had been working on technology to make emulating hardware/software designs more efficient as such designs got more complicated. At the time it was most common to emulate a system in an FPGA for testing, but as designs grew more complex this became a slower and slower process. IBM developed the idea of an emulation processor. This was to be known as CoBALT (Concurrent Broadcast Array Logic Technology). It was licensed to a company called QuickTurn in 1996. At its heart the QuickTurn CoBALT was a massively parallel array of boolean logic processors. Boolean processors are similar to a normal processor
but only handle boolean data, logic functions such as AND, OR, XOR, etc. Perhaps the most well known, is the boolean sub-processor that Intel built into the 8051, it excelled at bit manipulation. The same applies for the emulation processors in CoBALT. Each boolean processor has at its heart a LUT (Look Up Table), with 8-bits to encode the logic function (resulting in 256 possible logic function outputs) and the 3 gate inputs serving as an index into the LUT, as well as the associated control logic, networking logic, etc.
A target design is compiled and emulated by the CoBALT system. The compiling is the tricky part, the entire design is broken down into 3-input logic gates, allowing the emulator to emulate any design. Each processor element can handle one logic function, or act as a memory cell (as many designs obviously include memory). The CoBALT had 65 processors per chip, and 65 chips per board, with a system supporting up to 8 boards. This 33,280 processor system could compile 2 Million gates/Hour. The CoBALT plus sped this up a bit and supported 16 boards, doubling capacity and added on board memory.