Delay of four characters using CBREAK mode on RS/6000

Delay of four characters using CBREAK mode on RS/6000

Post by Robert Lupton (the Go » Sun, 14 Oct 1990 05:29:01



I have some code that runs on lots of machines and reads keystrokes
in CBREAK mode, using a BSD-style tty driver. Compiling with
        c89 -D_POSIX_SOURCE -Dunix
I get a delay of 4 key-strokes between when I type a character and when
my code sees and echoes it.

Any ideas?

                                Robert

 
 
 

Delay of four characters using CBREAK mode on RS/6000

Post by Kevin P. Kleinfelt » Tue, 16 Oct 1990 06:24:58



Quote:>I have some code that runs on lots of machines and reads keystrokes
>in CBREAK mode, using a BSD-style tty driver. Compiling with
>    c89 -D_POSIX_SOURCE -Dunix
>I get a delay of 4 key-strokes between when I type a character and when
>my code sees and echoes it.

Is NCHARS=5?  We found that changing the tty configuration via
stty TCSETA, while characters were present in the buffer, caused the tty
driver to insist on having all NCHARS chars in the input buffer, regardless of
the setting of NDELAY.  There is a fix (they created it for us).  It is new,
and involves replacing the driver. (Be sure they give you the fixed fix --
the first fix only changed the problem, and did not fix it!)
--

{emory,gatech}!nanovx!msa3b!kevin

"Don't hold your finger on the button if the motor ain't goin' roundy-roundy."

 
 
 

1. RS/6000 error msgs (Was: Re: RS/6000 survey - will post summary)

[LANG=En_US]  ksh: kjj: 0403-016 Cannot find or open the file.
[LANG=C]      ksh: kjj: cannot open

[LANG=En_US]  0506-764 ln: /tmp: Cannot use this command with a directory.
[LANG=C]      ln : </tmp> directory

 Canonicalizing all the error msgs by assigning them numbers and more
verbose explanations isn't such a bad idea, but it will hardly make
the system usable by secretaries. It does nothing to prevent an
accidental "rm *" or hide the details of the filesystem from the user.
Secretaries will run Motif and shrink-wrapped applications in
which case they will probably never [want to] use Unix shells. And they
shouldn't need to.
 The big gain here will be made by IBM SEs who will now be able to
look up customers' complaints by the error number.

    I haven't heard about IBM shipping *anything* on a Powerstation
yet. You can buy SunOS 4.1 *today* which is B2 certified.
And AT&T is advertising System V/MLS which is B1
certified -- I don't know if it's shipping yet.
    If security is important to you, you sure don't want to go with
a measly C2 rated system.

      ---Jason
-----

Jason Martin Levitt    P.O. Box 49860  Austin, Texas 78765  (512) 459-0055

UUCP    : cs.utexas.edu!hackbox!jason |  the American spirit and continues to
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