From: danielce@mullian.ee.mu.OZ.AU (Daniel AMP Carosone) Subject: serial woes Date: 29 Jun 1992 12:57:28 GMT
I'm sorry to say this, but at least in my experience the performance
of newer versions of Linux has been getting steadily worse by one
particular metric: serial port I/O.
With 0.12 (I didn't try serial comms with 0.11), and 0.95x, and 0.96a
(no patches), I happily connected a terminal at 9600, and at 19,200
only a very few characters were lost during sync -- enough to spoil
bulk transfers such as Zmodem, but perfectly usable for interactive
stuff. 0.96b dropped lots of characters, and now 0.96b.2 is dropping
characters like crazy, even at 2400 and 1200 bps. I daren't try 300.
In this case it's running on a slow, old, built-from-spare-parts 16Mhz
sx, so perhaps I'm seeing problems at a lower speed than others would,
but the trend of deterioration is quite clear. I'll try and run some
comparisons on the dx-40 when it's not in use.
I need serial port I/O - this box is eventually going to become my
router from the house network to the outside world via SLIP, since
it's not much good for anything else. :-) (for instance, it took about
2 hours to compile 0.96b.2 this afternoon)
I'm more than willing to spend time playing guinea-pig, testing
things, and suchlike, but I'm afraid I simply don't know enough about
serial drivers to make my looking at the code worthwhile.
On another, brighter note:
Mika, the new console support is a great improvement, especially
when used with the new termcap entry on a remote system. Many thanks!
Linus, heartfelt congratulations are in order over the results of
that `crashme' test. This is a well-deserved commendation for an
excellent system. Well done!
_______________________________________________________________________________
Daniel AMP Carosone. email: danielce@ee.mu.oz.au snail: 37 Wandin Road
Computer/Software Eng, IRC: Waftam Camberwell 3124
University of Melbourne. Vox: +61 3 882 8910 Australia