From: utzoo!decvax!duke!trt Newsgroups: net.unix-wizards Title: Re: TIOCIOANS, TIOCSIGNAL Article-I.D.: duke.2524 Posted: Sat Sep 11 21:17:38 1982 Received: Sun Sep 12 03:17:56 1982 References: cornell.3537,sri-unix.3113 I would like discussion of 4.2bsd in unix-wizards, if not for Berkeley, then for other UNIX implementors. I have read a preliminary report on 4.2bsd. It just desribed what is in the new kernel without attempting to explain what the features were good for. Here are my own impressions of 4.2bsd: 1) It is ENORMOUS. Yes, it no longer has the creat(II) system call. But instead it has a sophistiated open(II). And it has sophisticated network support. And lots more, like real-time features and IPC features. And the race to make them *sufficiently* sophisticated has just started. My guess is the 4.2bsd kernel will have twice the code of 4.1bsd. 2) It has things that are neither necessary nor sufficient. a) kernel-level file locking, a subject which has generated many a flame. The locking is quite rudimentary--why bother? Was it required by DARPA? b) New "readv" (and "writev") system call, which replaces a sequence of read(II)s with a single "readv". Why? Efficiency? Indivisibilty? Couldn't there just be a "sysv(syscall, args, syscall, ..., 0)"? 3) It has things which are unproven, at least in the UNIX domain. a) The "dwrap" system call, which was vaguely described and which provides access to the networking code. b) Symbolic links. c) File names up to 255 characters long (and new directory file format). d) Many others (sorry, I can not remember them offhand). In summary, 4.2bsd appears to be an aggressive, innovative undertaking which provides a far bigger "feature-fest" than did 4.1bsd. Some new features sound wonderful, but only time will tell which are buggy, which are robust, and which are used. The system interface is so different from UNIX V7 that many would argue it is not a UNIX at all. Tom Truscott (duke!trt)