Type-ahead in unix

Dik T. Winter dik at cwi.nl
Wed Apr 3 11:23:19 AEST 1991


In article <5930 at tahoe.unr.edu> malc at equinox.unr.edu (Malcolm Carlock) writes:
 > In article <659 at adpplz.UUCP> martin at adpplz.UUCP (Martin Golding) writes:
 > -In <7297 at utacfd.UUCP> nomura at meap.uta.edu (S. Nomura) writes:
 > ->I am accustomed to the type-ahead feature of the VAX/VMS.
 > ->Is there any easy way to inplement this in unix ? Thank you.
 > -Boy, are you running on the wrong OS. Our vendor is going to assist
 > -us in re-programming the terminal controller so we can get decent
 > -typeahead, NOBODY has had any other useful suggestions. It's 
 > -worthwhile for us because we have lots of these things; otherwise
 > -your choice is pretty much to suffer in silence.
 > Huh??  What are you talking about?  All the Unices I've used, since V7
 > on a PDP-11 to SunOS 4.1, have had decent type-ahead, so decent in fact
 > that I've never had to worry about overrunning it.  What manner of Unix
 > are you guys running, and what applications??

Enter the difference between VMS type-ahead and Unix type-ahead.  Under VMS
type-ahead is not echoed until it is actually needed.  Unix type-ahead is
echoed immediately.  (This is a generalization of course and depends a bit
on the Shell you are using.)  I have used both and see advantages of both.

1.  In VMS style type-ahead your output will never become garbled, but Unix
    types have a garbled view of course.
2.  I prefer the Unix style when there is no output currently generated.
    Also some times when output *is* generated (ever attempted to kill
    yes hello&  ?).
3.  Also Unix style type-ahead has a tendency to get lost (when switching
    from nocbreak to cbreak etc.).

The answer to the original question is: no VMS style type-ahead can not be
implement given the current set of tools.
--
dik t. winter, cwi, amsterdam, nederland
dik at cwi.nl



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