Back when the dinosaurs were using card readers (and yes, I've used a card reader on Unix; I think it was a desktop CDC model, and the driver would handle two modes: strict 80-column i.e. one 12-bit column per 16-bit word and you got 80 of 'em on a DMA channel, or ASCII NL-terminated after last non-blank column, and no, I have no idea whether it handled EBCDIC or CDC etc, but I digress as usual). Where was I? Oh yes, sleeps... Back when sleep(3) was sleep(2) (yes, Virginia, sleep() used to be a system call, then it became alarm()/pause(), and now it seems to be nanosleep(), and I'm wandering again), you never called sleep(1) because its granularity was +/-1 second (and all the way up to +infinity, actually, on a really busy machine), thus it could return right away, with ensuing hilarity. So, I'm curious: When did sleep(2) become sleep(3)? Was it V7, or some BSD? Or Babbage help me, SysVile? When did the caveat about sleeping for 1 second become known? I don't think that I ever saw it documented, but was one of those "lore" things passed around at Unix conferences and the like. And when did it start using nanosleep() instead of alarm()/pause()? I see that my Penguin box has a bet both ways; it "may" use SIGALRM[a] (thus "mixing calls to alarm(2) and sleep() is a bad idea" (well, I've used both), and also refers to nanosleep(). [a] Alpine's spell-checker suggested "SICKROOM" here; pretty close when dealing with timed-out reads on a TTY connection[ii] :-) [ii] Have you tried this with Perl? You can't rely on EINTR[3], so you have to use eval{} blocks instead, and it starts getting pretty fugly... [3] And here it suggested "ENTREE". -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."