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From: jbvb@FTP.COM ("James B. Van Bokkelen")
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re:  Sources for Telnet/FTP Servers for DOS and OS/2
Message-ID: <9104161246.AA04464@ftp.com>
Date: 16 Apr 91 12:46:38 GMT
Sender: rwh@ucbvax.BERKELEY.EDU
Reply-To: jbvb@ftp.com
Organization: The Internet
Lines: 28


    ...I never have understood the network vendors reluctance to provide a
    full suite of TCP/IP software for PCs under DOS.  For every client
    application there should be a server application....

What you think is reluctance is actually inability.  Unless you have a
386 processor, it is simply impossible to build something that can trap
every possible way an application might write to the PC's screen or read
from the keyboard, so that *all* applications can be run from the Telnet
server.  The two extant academic efforts will probably work with 60-70%
of available DOS applications.  With a lot of work, and a long learning
curve, you could probably get that up to 85-90%, but I have no interest
in shipping something that might be returned as unusable by 1 customer
in 10.

A second problem is the Telnet Network Virtual Terminal model, which doesn't
map cleanly to the PC's directly addressable display memory and keyboard
hardware.  If the application displays a bright violet on green smiley-face,
or goes into graphics mode on your EGA, what do you tell the real or simulated
VT100 on the other end to print?  What does the user have to type when the
application is looking for Alt-LeftShift?  Carbon Copy and PC/Anywhere have
their own proprietary datastream, designed to handle the PC's capabilities,,
and the job is simpler because both client and server are PCs.  If you want
to do a good mapping with public protocols, you're probably going to wind
up with X...

James B. VanBokkelen		26 Princess St., Wakefield, MA  01880
FTP Software Inc.		voice: (617) 246-0900  fax: (617) 246-0901