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3.3 Recording Control Software

This software runs in the foreground of the Recording PC. It allows the user to open address trace files on the hard disk and should also provide file deletion, compression, and network transfer options. When the user selects ``Start'' the control program writes to Bullwinkle's I/O port, clearing the buffer and signalling via the ribbon cable for Rocky to commence tracing. Once the preset file size is reached or the user aborts the program, a port write is made which transmits a stop command and then flushes the buffer contents to disk.

While tracing is going on, the program continuously polls an I/O port until the high-water mark is reached AND Rocky has signalled that it is stalled. Using the DOS interrupt 21h routines, the program initiates up to four block memory-to-disk transfers. Before each, it selects exactly one of the modules by writing to a port location. This way, the 256 kB on the board can be mapped into the 64 kB block in memory locations D0000-DFFFF, an area reserverd for expansion card ROMs and memory for network cards, for example. If this location conflicts with other devices, it can be mapped to the E000 segment instead via a jumper.

This software has not been written; at this point only a simple program called capture exists which dumps the traced values to the screen. However, this was useful for verifying correct transmission from one PC to another over the ribbon cable.



Scott E. Harrington
Sat Apr 29 18:56:25 EDT 1995