A/UX: BBX Works with A/UX 3.0 (9/94)


There is a problem with the A/UX pseudo-tty driver when running BBX (a 4GL development tool from BASIS International). Here is a detailed description of the problem:

When I open a pseudo-tty with the O_NDELAY flag, some of the output
doesn't show up on the screen until AFTER I type a character on the
screen. The pty is opened unbuffered -- this is something internal to the
system. The first half of a page of text prints out. I have to type
something to print the rest of the page.

This doesn't happen on the console or serial ports -- only the ptys.
I'm using read() and write(), not stdio, and it's unbuffered. Doing an
ioctl(tcsetaw) on the fd of the pty fixes the problem, but shouldn't be
necessary.

There is a new kernel patch for the problem between A/UX pseudo tty and BBX. We tested the BBX software with the new kernel, and it works well. This patch fixes the longstanding problem between A/UX and BBX. This fix is now included in A/UX 3.0.



Article Change History:
09 Sep 1994 - Reviewed. Changed title.
31 Aug 1992 - Reviewed.

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Published Date: Feb 18, 2012