chris@SALT.ACC.COM (Chris VandenBerg) (02/26/89)
Morning all... Having just read Excelan's announcement for their new terminal server the thought once again crossed my mind that no one seems to see the need for these things to try and do TN3270. I get requests from customers every day for a product like this but it seems that no one has the bugs worked out yet. I threw this query out on the net almost a year ago, fully expecting a commercial product long before now. Does anyone know of a box that will do TN3270 for the dumb terminal user? PLease let me know if anyone has the inside scoop and I'll try and sumarize the responses to the net. THis might be some start-up's road to fame and fortune (:*) Chris VandenBerg ACC(chris@salt.acc.com) Standard disclaimer - My employer knows I can't do any REAL damage so they humorme.
schoff@STONEWALL.NYSER.NET ("Marty Schoffstall") (02/26/89)
Chris,
One of the problems here is mapping the 327X stream into a ascii/ansi terminal
of some type (where some type is one of at least a hundred). Carrying all
this "curses" (forgive me) information around in memory is very wasteful. A
standard protocol might help vendors (and definitely users). This protocol
upon identification of terminal type to the terminal server would ask some
server (who has disk storage) what is the curses defnition for this terminal
to be mapped into. Sounds like an IETF Working group.
Another place to possibly look is how ISO VTP with forms mode does this, knowing
them they probably have left it up to a vendor's agreement.
Marty
PS: I'm not suggesting you use curses it is only something generally known
--------------------------your message----------------------
Having just read Excelan's announcement for their new terminal server
the thought once again crossed my mind that no one seems to see the need
for these things to try and do TN3270. I get requests from customers every
day for a product like this but it seems that no one has the bugs worked ou
yet. I threw this query out on the net almost a year ago, fully expecting a
commercial product long before now. Does anyone know of a box that will do
TN3270 for the dumb terminal user? PLease let me know if anyone has the
inside scoop and I'll try and sumarize the responses to the net.rick@GATEWAY.MITRE.ORG (02/28/89)
This is off the original subject of availability of forms-oriented terminal servers, but I thought I'd agree with Marty about a terminal description server... You are correct about the exchange of curses-type information not being covered in the ISO VT standard. It's generally considered that this is only useful for the mapping of VT updates to a specific terminal type, and is therefor a "local" rather than a "peer to peer" protocol matter. The VT standard only defines communications between 2 peer VTs and doesn't have an idea of a terminal description server. I suppose in the ISO world the proper way to look at this may be to register the terminal information in the directory. (could a name domain record type be devised for this?) This may take care of the need for a protocol to distribute the info, but it definitely still requires standards for the format of the information. Maybe there needs to be more than one format for different terminal classes (possibly screen-oriented ala curses, forms-oriented, and graphics). This kind of information might be used by a variety of clients: 1. terminal servers, as you suggested 2. TELNET or ISO VT client programs. This would be to help them map either generic VT updates to a physical terminal, or one type of data stream (ie. 3270) to another (ie. async dumb terminal). 3. applications that want to control terminals directly. This, of course,contradicts the VT idea that anything being sent across a network to a terminal should be in a standard (device-independent) format. On the other hand it is exactly what happens when someone telnets to a remote unix box and fires up "vi". A well designed, standard representation (or set of representations) for the terminal capability data may just expand this approach beyond curses/termcap/terminfo. Wasn't there a project some years ago at Berkeley to define a termcap-like description for graphics terminals? Anybody know about it? By the way, it's not yet clear what method of supporting forms-oriented applications will be popular using ISO VTP. There is a FORMS VT profile defined by the NIST OSI workshop, but some favor the idea of sending 3270 data streams through a "transparent" VT (ala tn3270). Here at MITRE we have a prototype of a VT FORMS implementation and are looking for someone to test interoperability with. This implementation uses curses to map VT FORMS updates to async. terminals. -Rick Wilder (rick@gateway.mitre.org)