Subject: Re: commenting nitpicks in if_sl.c
To: John Vinopal <email@example.com>
From: Scott Reynolds <scottr@Plexus.COM>
Date: 02/18/1995 09:48:57
On Fri, 17 Feb 1995, John Vinopal wrote:
> This last line is quite in error. Waiting for 1/2 of a 1024 byte
> packet is 512 / cps. On a 9600 line, cps is 1200. So that makes
> a 426ms wait for a 1024 MTU at 1200 cps (9600).
Faulty assumptions here lead to your erroneous times. You forgot that
each character is preceded by a stop bit and followed by one or two stop
bits (but for most PC hardware and 8 data bits, only 1 stop bit). In
other words, 9600/(1+8+1) = 960, and 1/2 * 1024 / 960 is indeed 533ms.