Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!cs.utexas.edu!uunet!tektronix!percival!bucket!leonard
From: leonard@bucket.UUCP (Leonard Erickson)
Newsgroups: comp.dcom.modems
Subject: Re: xyzmodem problems
Message-ID: <1409@bucket.UUCP>
Date: 23 May 89 20:21:28 GMT
References: <24404@agate.BERKELEY.EDU> <1399@bucket.UUCP> <765@omen.UUCP> <24552@agate.BERKELEY.EDU>
Reply-To: leonard@bucket.UUCP (Leonard Erickson)
Distribution: usa
Organization: Rick's Home Grown Unix; Portland, OR
Lines: 31

In article <24552@agate.BERKELEY.EDU> ked@garnet.berkeley.edu (Earl H. Kinmonth) writes:
<By the way, am I "wrong" in thinking that the apparent assumption of a
<clear eight-bit path in the [xy]modem protocols represents {naive|
<brain-dead|criminally stupid} programming? Was there something
<different about the world when these protocols were written that a
<clear eight-bit path could be assumed? Maybe because I'm an historian
<and not a programmer, I would start from the assumption that any
<communications protocol ought to have as a fall back option nothing
<better than a BCD character set. (Anything less, and you may as well
<revert to carrier pigeons.)

Xmodem was written by Ward Christenson(sp) back in the late 70's. It was
intended to allow two *people* to xfer files between their personal
computers over a phone line. So complete control of the channel was a
"given". So was operator intervention if things went greviously wrong.

Other oddities of the protocol come from its CP/M origins. 128 byte
blocks were used as that was one sector on a disk.

Xmodem is fine for what it was "designed" for. It's not so hot when ported
to odball environments. (from the viewpoint of it's original users, I'm
sure that mainframes and minis are oddball)

BTW I consider the *non*-availability of a clear 8-bit path to be a
clear indicator of brain damage. 

-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Short