🚀 go-pugleaf

In article <1992Oct21.183809.5933@portal.vpharm.com>, sergio@portal.vpharm.com (Sergio Rotstein) writes:
- 
- when I telnet to my vax (that runs vms) from an sgi machine, the backspace
- key which is used for delete on the sgi, just moves my cursor to the beginning
- of the line on the vax. in unix, you can reprogram the keys by using the
- "stty erase ^H" command. 

Digital appears to be very proud of that behaviour, as it gives the ascii
'bs' character a new meaning that was (before VMS) unheared of. It also ensures
that users connecting via noisy lines or lines which use 0x7f as a sync 
character cannot get very far on a VMS systems. The ISO 646-1983 states (I 
quote from BS 4730-1985)

DEL DELETE
A character used primarily to erase or obliterate an erroneous or unwanted
character in punched tape. DEL characters may also serve to accomplish 
media-fill or time-fill. They may be inserted into, or removed from, a stream
of data without affecting the information content of the stream, but such 
action may affect the information layout and/or the control of equipment.

In plain text: DEL is all seven (or eight if even parity) holes in the 
punched tape punched, thus can be used to obliterate any other character.
When you punch tape, you must backspace once you mistyped, then push delete
to obliterate, then type the correct character. If you then fed the punched 
tape into the console, it ignored short bursts of delete, and for longer
bursts (20 or so) would switch back to keyboard input.

I guess the meaning of DEL under VMS was carefully designed to ensure that
people with punch tape tty consoles would just go away in disgust, as their
command tapes were not useable. (N.B. I can remember having a box of such
tapes for commonly used command sequences - much like shell scripts now)

- Is there any equivalent to that under vms, or any of the "set term" options
- which would allow me to do that?

No, in effect the VMS terminal access system has the terminal all the time
in a "screen-like" mode, similar to the one you get on unix with the Korn
shell or the various enhanced C-shells. Thus you would have to generate a 
full terminal description for the terminal. You can do that under VMS, but
it is well hidden - look in the TPU user or programmers guide.

It is, however, not as common under VMS to define terminals, partly because
virtually every terminal claims to have a VT100 emulation (mostly poor),
partly because many applications will do their own key-code processing 
anyway - EDT was a notable culprit the last time I looked at it, but that
may have changed since. You also get only eight - FT1 to FT8, no choosing
your own names.

It also was -very- difficult to get VMS administrators to install the 
terminal definitions in the system, and afaik no way to use and test 
them before they are thus installed. (Read: I copped out before getting
anywhere)

The best thing you can do is just to grin and bear it, and use the delete
key in the edit key cluster to get an erase action, and ctrl-e to go to
the end of the line again whenever you press backspace inadvertently.

                                      Thomas

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