DECMate III

<As far as OS/278 and WPS goes, the video/keyboard is the console. The <console is run via a combination of hardware and slushware; the slushware <provides terminal emulation services and the hardware provides the hooks Slushware is the embedded system tracks that do terminal and keyboard work. <needed by the terminal emulation services to appear as a normal console <type serial device to OS/278 and WPS (which expect to talk directly to <the console UART rather than via some sort of device driver). If you were to reassemble os/278 it's possible to redirect it to a serial port. Not a trivial task for a PDP-8 novice. It is doable as the sources are on the net. <If you are sufficiently technically equipped and inclined, it should be <possible to switch the console port (on which the emulator runs) and <the 9-pin serial port for the printer. The first thing done by the <firmware (before it checksums the ROM and loads the slushware) is to <program the I/O addresses of the various hardware ports. It is possible <to switch a few instructions in the initialization sequence to swap the <addresses of the printer and console ports. Although I've _thought_ about <doing this and investigated far enough to determine that it ought to work, <I've not actually _tried_ it, so I could be wrong. No good. The control software is very port specific. <There are a number of fun bits involved. The PDP-8 is a 12-bit machine. <The ROMs are 8-bit parts (2716s). There are three ROMs, providing a <4Kx12 memory image for the PDP-8. The ROMs are interleaved in a funny <way; I figured it out once and Lasner was able to use the information to <extract a ROM image and disassemble it, but that was a few years ago. I'd <have to figure it out again. I think I have that on line. The slushware is where all the interesting stuff is. Allison