The SINDE Project

In August, 1982 the Laboratorio de Sistemas Integrados at the University of Sao Paulo needed serious computing power for VLSI CAD and process simulations. It already had developed graphic terminals, so a group was set up to integrate commercial VERSAmodules with Motorola's VERSADos real time operating system.

By early 1983, however, it was decided that ( given the Lab's resources and cost structure ) it would be cheaper to design the whole machine in-house. Jecel Assumpcao Jr headed the hardware design while Osvaldo Cristo was in charge of the OS. Jecel's micro background and Osvaldo's knowledge of mainframes combined with a few ideas inspired by Intel's iAPX432 architecture resulting in an interesting design.

Both symmetric and asymmetric multiprocessing were used to achieve scalable performance. The highly modular design also reflected the move to the smaller VERSAmodule European ( VME ) form and the low density logic then available. VME's arbitration logic was enhanced to allow a greater number of bus masters ( it ended up looking like what NuBus or FutureBus use ). A SINDE computer was to be built from one or more of each of these modules:

Notable for their absence are system-wide interrupts. All communication between processes or processors was via messages. As processes lacked shared memory, there was no cache coherency hardware ( the ready queues and message queues were in non-cachable memory regions ).

The bulk of what is normally the OS ran as regular processes in the GPPs, while the low level I/O ran as "embedded" processes on the character and block I/O boards.

Besides the message passing micro-kernel parts of the OS design, several features predated their popularization in other projects:

Simulations showed that three or four GPPs would be the practical limit, but some configurations might prefer to beef up the I/O instead.

In late 1984, the project changed as financial backing from Prologica made fast results a priority and the original designers moved on to projects outside LSI. Three generations of uniprocessor Unix-clone boxes followed, with the multiprocessing theme fully explored in the 1987 MS8701 hierarchical, shared memory project.

see also:
| merlin | | jecel | | ms8702 | | sinde |
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| LSI | | USP |

please send comments to (Jecel Mattos de Assumpcao Jr), who changed this page on Jun 29, 17:08 .