Subject: serial port silo overflow repair
To: None <tech-kern@NetBSD.ORG>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-kern
Date: 07/29/1997 00:45:07
On Mon, 28 Jul 1997 22:41:13 -0700,
"Erik E. Fair" (Time Keeper) <> writes:

.We've had a recurring problem with serial port "silo overflow" conditions
>happening in various versions of NetBSD on various platforms

Eek. I forgot to ask. Which ports, specifically? And which versions?
And how  fast are the serial ports, and how deep the FIFOs/silos?

If a CPU as slow as a Vax-11/750 (the comparison point of the week,
apparently) can keep up with a half-dozen DZ-11s, we should be able to
manage respectable serial I/O on *most* ports.

(yes, yes, I know, the UBA750 is/was more efficient at interrupt
vectoring than the UBA780, and the 4BSD dz driver had interpolated
assembler doing pdma, but we're talking about an 0.6-mip machine
handling an aggregate of 6x8x4800 == 230kbaud, peak ...)