Type-ahead in unix

Doug Gwyn gwyn at smoke.brl.mil
Fri Apr 5 04:51:51 AEST 1991


In article <671 at adpplz.UUCP> martin at adpplz.UUCP (Martin Golding) writes:
>If you call it supported. If you call that typeahead.

Yes on both counts.

>BTW ksh on my machine cannot process typedahead edit commands.

Sounds like a bug in the implementation of ksh.  The same feature
in BRL's version of the Bourne shell does not have that problem.
(The editing of course does not occur until the shell reads the
characters, but they do have the desired effect at that point.)

>How about, typeahead for passwords?

Why do you often find yourself typing passwords?
In any case, you can type them ahead, but they will be echoed.
Or, you could wait until you are prompted, just in case the
program ends up asking for something other than a password at
that point, so you won't be embarrassed by having entered a
password that ends up getting displayed.

>How about, screen formatting programs?

I don't know what problems you see there.

>I just got out of a meeting with our vendor about this very subject-
>the terminal drivers are deliberately programmed against us. When
>you do disk stuff, the input doesn't start until the process asks:
>terminal stuff is crammed willy-nilly into the memory, so the controller
>doesn't have to be annoyed by the processes.

The fundamental difference is that the data source for keyboard
input is forced upon the operating system whether or not it wants it,
so it must do something with that input.  The disk is read only upon
decision of the operating system, not of the disk.

Basically I would suggest simply getting used to the UNIX input
style.  It is not much better or worse that what you are accustomed
to, merely different.



More information about the Comp.unix.questions mailing list