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