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Subject: 
Re: VT100 over the web
Newsgroups: 
lugnet.off-topic.geek
Date: 
Wed, 21 Jun 2000 16:33:43 GMT
Viewed: 
118 times
  
In lugnet.off-topic.geek, Larry Pieniazek writes:
We are trying to determine the feasibility of replacing client side installed
VT100 emulation software with a server side component that renders an emulated
VT100 terminal (or its contents anyway) via a browser.
I suspect that doing so with static or generated HTML is not practical but
haven't disproven it yet.

I'd tend to agree with you on that.  VT100 with half duplex continually sends
screen updates with every keystroke (1), after which it needs to render the
escape codes (termcap?) properly.  Server performance would take a serious hit,
both in rendering this into HTML to refresh the browser window, and in sending
these tiny sessions over HTTP.  Even disregarding net lag for a moment, most
browsers aren't built to refresh themselves at such a fast rate.  *Then* I
bring up the hot topic of latency...

I would strongly argue for some form of active content on the browser end,
especially considering how simple the telnet protocol is.

I suspect that doing so with a java applet (that perhaps just supports the
Vt100 protocol stream, or perhaps interacts with a serverside component that
does the protocol conversion) might be possible, but as to how practical?? gut
says not all that practical. Certainly I haven't turned up any products yet.

Certainly, it's possible.  I can probably scrounce up a few today or
tomorrow, time permitting.  Anywho, my personal fave, a GPL'd SSH1 term that
runs as an applet *and* an application (and BTW forwards ports very well), is
right here:

http://www.mindbright.se/mindterm/

There are several links to applet demos halfway down the page (2).  The
downside to this is, of course, the Java security model which generally
restricts applet network connections to just the server.  You can get around
this with signed applets and some configuration on the client end, tho.

Cheers,
- jsproat

1.  I believe this is the case, but I haven't done a packet capture to verify.
It *might* just send deltas.  At any rate, some small amount content is sent
back with every keystroke.

2.  But don't use the hyperlinks without BT's approval.  I guess you could view
the HTML source, jot down the links, and then type the links into your
browser...  :-P



Message has 2 Replies:
  Re: VT100 over the web
 
(...) (24 years ago, 21-Jun-00, to lugnet.off-topic.geek)
  Re: VT100 over the web
 
(...) Whoa. A google search on "java telnet" and "java vt100" turns up a bunch of matches. I also checked Sourceforge and JARS. Some highlights: "Java Telnet Application/Applet v2.0" -- (URL) Application & Applet v0.9b" (pages are in Korean, I (...) (24 years ago, 21-Jun-00, to lugnet.off-topic.geek)

Message is in Reply To:
  VT100 over the web
 
Is it even possible? My researches so far have not turned up a product, and in thinking about the problem, the VT100 protocol stream is richer than HTML, in some ways of looking at it. We are trying to determine the feasibility of replacing client (...) (24 years ago, 21-Jun-00, to lugnet.off-topic.geek)

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