A safe vertex

Abstract

The VERTEX message passing system provided with NCUBE hypercubes is unsafe. The system can fail under high message loads. We have implemented a message passing system with the same "look and feel" as VERTEX but which is instead based upon the crystal_router running at clock interrupt time. The system is written mostly in C with a few bits of assembly code to run the DMA devices. This implies that safety checks (are the buffers full?) and complex error handling mechanisms can be easily implemented at the C level. A first version works, is safe, and is faster than VERTEX in the high volume limit, slower in the low volume case. At the very least, this system will be interesting for high message traffic applications, such as disk backup.

Additional details