Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!csd4.milw.wisc.edu!mailrus!cornell!batcomputer!sun.soe.clarkson.edu!mrd From: mrd@sun.soe.clarkson.edu (Michael DeCorte) Newsgroups: comp.unix.wizards Subject: V68 - what does disjointio do? Message-ID: Date: 12 Jun 89 17:53:14 GMT Sender: news@sun.soe.clarkson.edu Organization: Clarkson University, Postdam NY Lines: 43 Hello, I hope someone can help me with a problem I have been having. I am modifying a tape driver for V68 (Motorola's SysV.3 for 680x0's). After reading the code I am left with a few questions. The code uses disjointio but I can't find any docs on it. as best as I can tell I you pass it an memory location of an object the size of the object and an array that gets filled up with the real address for each fragment of the object. But I don't know if there are any side affects. I assume that it will pull in any pages that aren't in real memory off of disk but does it lock them? If it does how do they get unlocked? You see I can't find any place where the memory pages are getting locked or unlocked. If disjointio doesn't do the locking who does? I have some ATT docs that say dma_breakup can do it but these same doecs say "If your device has special hardware for performing scatter-gather transfers you should not use this routine." Well I have scatter-gather transfers and if my guess is correct using dma_breakup will give me a very large penalty. "Writing a Unix device driver" says I should use vslock and vsunlock but I don't have these routines. (I checked with nm). So if you know what disjointio does or how to lock or unlock page or what manual/book/whatever documents this stuff please drop be a note. thanks -- Michael DeCorte // (215)546-0497 // 2300 Naudain St. "H", Phil, PA 19146 Internet: mrd@sun.soe.clarkson.edu // Bitnet: mrd@clutx.bitnet --------------------------------------------------------------------------- Clarkson Archive Server // commands = help, index, send, path archive-server@sun.soe.clarkson.edu archive-server%sun.soe.clarkson.edu@omnigate.bitnet dumb1!dumb2!dumb3!smart!sun.soe.clarkson.edu!archive-server ---------------------------------------------------------------------------