Attention AIX users:

Many people have reported having problems getting QuickPage to work on the AIX platform. In every case, the symptom is exactly the same: qpage gives up too early when initializing the modem, sending the dial command, or waiting for the modem to connect.

Unfortunately, I do not have access to any machine running AIX, nor do I have any contacts at IBM who can explain what is causing the problem. Based on feedback from several helpful system administrators, it is my conclusion that this problem is caused by a broken select()/poll() implementation in some versions of AIX. One person claimed the problem only started happening after he installed some year-2000 patches on his machine.

I do not have specific details about which versions of AIX suffer from this problem. If qpage works fine on your AIX system, please let me know which AIX version you're using and what patches (if any) are installed. If qpage does not work on your system and you happen to find a workaround, please let me know so that others can benefit from your discovery.


Update! 8/16/98

Thanks go to David VanCleve from NeoSoft who suggests that the AIX bug might not be related to select()/poll() at all. It's possible that select()/poll() are working correctly and that the real bug is in read().

David points out that setting c_cc[VMIN]=1 in the termios structure makes qpage work under AIX 4.2.1. QuickPage currently sets c_cc[VMIN]=0 so that read() will not block indefinitely while waiting for a character. It is possible that a termios bug in AIX 4.2 causes read() to always return zero if c_cc[VMIN]=0, even if data is available for reading (as indicated by select()/poll()).

I am working on a fix to test this theory. If you would like to help by testing my workaround on your AIX 4.2 system, please let me know.

Update! 5/8/99

Gareth Richards just informed me of the following:

I'm just trying out qpage for our team messages, and am installing on AIX
4.2.1, I suffered an immediate closure of the modem port as suggested in
'ixo.c'. Looking on the IBM web page I've located the fixes...

The fix sets required for the select bug in AIX are

U457885   (AIX 4.1.x)
U458478   (AIX 4.2.x)
U460835   (AIX 4.3.x)

the url is

Basically an upgrade to bos.rte.tty, this fix may in turn require further
fixes to other files.

Having installed this fix, qpage (beta6) appears to be working fine
Thanks Gareth!