Re: newbie needs advice

[dempson@actrix.gen.nz (David Empson)]

Sagochangi <sagochangi@aol.com> wrote:

> >When the card is fixed, even
> >a nonaccelerated 1Mhz Apple IIe with ProTERM can pull 19.6k
> >port speeds using a 14.4k modem.  I've done this myself.  Characters
> >do not drop.
> 
> Ick.  Then why do I keep dropping characters on my GS then, past 9600?  I'm
> sure I've got a handshaking cable, and the settings are right.

Using what software?  ProTerm?  If so, did you boot directly into
ProDOS-8, or via GS/OS?

Depending on your system configuration, booting via GS/OS tends to loads
lots of extensions which hog CPU time by making use of various
interrupts.  This leaves much less time for communications software to
handle the serial ports.

Try shift-booting to disable your extensions and see if that makes any
difference.  Also try booting directly into ProDOS-8 for comparison.

A particularly bad culprit is AppleTalk, which hogs the CPU for up to 20
milliseconds every time a packet is transmitted or received.  (This is
long enough to lose up to 20 received characters at 9600 baud.)

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand