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From: dafa@ihwpt.UUCP (David Fay)
Newsgroups: net.micro.mac
Subject: Re: Red Ryder questions.
Message-ID: <651@ihwpt.UUCP>
Date: Tue, 21-Jan-86 00:20:45 EST
Article-I.D.: ihwpt.651
Posted: Tue Jan 21 00:20:45 1986
Date-Received: Wed, 22-Jan-86 04:38:14 EST
References: <1170@utai.UUCP> <277@ism780c.UUCP>
Organization: AT&T Bell Laboratories
Lines: 49

> The current version of Macterminal, when it thinks it is talking to
> another mac, uses a modified xmodem protocol.  It essentially does
> three xmodem transfers, one for the header, one for the data fork,
> and one for the resource fork.  This is not compatable with any
> standard xmodem, and so will not work with other terminal emulators.
> In particular, it uses a different handshake at the start to get
> the transfer going. *sigh*

I used to think MacTerminal was just perverse in it's insistence on
a nonstandard XMODEM protocol until a friend pointed out to me that
MacTerminal protocol is "sender initiated" rather than "receiver
initiated". What this means is that if I do a macput on the Unix end
(the sender), I don't have to do anything on the Mac end (if it is running
MacTerminal). This is a wonderful feature since it means I can easily
download multiple files with no human intervention on the mac end. I
can even call a Mac that is unattended but running MacTerminal and transfer
files to my heart's content (or, more accurately, until the disk is
full).

Compare this to a MacBinary transfer as implemented in Red Ryder for
example. Since MacBinary transfer uses standard XMODEM protocol, it is
receiver initiated. This means that I have to do something on the Mac
end first before the file transfer can take place. Thus I can't transfer
multiple files without telling Red Ryder repeatedly to initiate the
transfer. I realize that it can be probably be done with Service
Procedures, but what a pain compared to MacTerminal. Even worse,
if the user interface is poorly written, as it is on Red Ryder, I
will even have to name the file before the transfer begins. This is
stupid since the MacBinary format includes the name of the file, which
will overide my name anyway. The correct way to do this, as suggested
by Dennis Brothers, in his original MacBinary proposal, is to ask
the user for a name at the end, not the beginning of the transfer, and
only if it turns out that it wasn't a MacBinary transfer at all but
a simple XMODEM transfer.

By the way, MacTerminal 2.0 is out. My local dealer received his dealer
copy today (Monday). MacTerminal 2.0 supports both MacTerminal
and vanilla MacBinary transfers. It also apparently includes a menu
selection for Saving Screen, which implies to me that the annoying
default save has been turned into an option.

David Fay
ihnp4!ihexp!dafa
-- 
--------------------
David Fay
AT&T Bell Laboratories
Naperville, IL 60566
ihnp4!ihexp!dafa