Path: utzoo!mnetor!uunet!mcvax!botter!ast
From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: Problems with serial TTY driver
Message-ID: <1778@botter.cs.vu.nl>
Date: 9 Dec 87 15:36:52 GMT
References: <2314@encore.UUCP>
Reply-To: ast@cs.vu.nl (Andy Tanenbaum)
Organization: VU Informatica, Amsterdam
Lines: 16

In article <2314@encore.UUCP> paradis@encore.UUCP (Jim Paradis) writes:
>Is there some limit to how fast MINIX will take interrupts? 
>If one takes them too fast, will messages get lost?
>
If you try to force feed MINIX from an Ethernet at 10 Mbps it will probably
drop stuff.  There is undoubtedly a limit on how many interrupts per second
it can handle, but an AT it should be over 1000 per second.

The original tty driver was very carefully written to deal with exactly
this issue.  When characters come in, they are buffered, even if it is
not possible to send a message to the tty task.  This code is on lines
3528 to 3552 of the book.  Assuming you are still using this mechanism,
you ought to be able to accept characters at say 2400 baud without losing
any.

Andy Tanenbaum (ast@cs.vu.nl)