Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site utcs.uucp
Path: utzoo!utcs!flaps
From: flaps@utcs.uucp (Alan J Rosenthal)
Newsgroups: net.micro.apple,net.dcom
Subject: Re: Data Protocol Question
Message-ID: <947@utcs.uucp>
Date: Wed, 30-Oct-85 20:10:24 EST
Article-I.D.: utcs.947
Posted: Wed Oct 30 20:10:24 1985
Date-Received: Wed, 30-Oct-85 21:26:56 EST
References: <557@ihlpm.UUCP>
Reply-To: flaps@utcs.UUCP (Alan J Rosenthal)
Distribution: net
Organization: University of Toronto
Lines: 19
Xref: utcs net.micro.apple:2253 net.dcom:1425
Summary: 

In article <557@ihlpm.UUCP> terry2@ihlpm.UUCP (t. nelson) writes:
>I am now exploring the world of Bulletin Boards.  Most seem to 
>use various forms of data exchange protocol like XMODEM or
>XMODEM/CRC.  Access II uses Christensen (sp?) protocol.  I have
>been told that XMODEM and Christensen protocols are the same.
>Is this true?  What's the difference between XMODEM, XMODEM/CRC
>and some other popular protocols?

XMODEM describes how each individual block is sent.  Ward Christensen
is XMODEM protocol with a particular description of block 0, and the
fact that the other blocks are data blocks.
I will post a (technical) description of the protocol if requested.

CRC stands for Cyclic Redundancy Check.  It is a complex form of checksum.
I would assume that XMODEM/CRC is just an XMODEM that outputs the CRC after
transmission.

Alan J Rosenthal
{ihnp4|allegra|linus|decvax}!utzoo!utcs!flaps, cbosgd!utcs!flaps