norskog@fortune.UUCP (Lance Norskog) (01/31/84)
Folks, I blew it. The Fortune screen does not update at 45kbaud, it updates at 45k chars/sec, or 450kbaud. This is from a test which just writes a 2000-char buffer of ascii text. The screen hardware is a simple character generator, with 8 bits of attribute space for each 8 bits of character. Our architecture allows the screen driver to reside in fast (expensive) RAM or slow (cheaper) ROM, with a 3/2 performance hit. We put it in ROM. When we had it in RAM, it ran at 75k chars/sec. Obviously, a tty driver page mode is not a luxury in this situation. Lance C. Norskog Fortune Systems, 101 Twin Dolphin Drive, Redwood City, CA {cbosgd,hpda,harpo,sri-unix,amd70,decvax!ihnp4,allegra}!fortune!norskog