Xref: utzoo comp.os.misc:1422 rec.ham-radio:28938 Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!usenet.ins.cwru.edu!ncoast!allbery From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR) Newsgroups: comp.os.misc,rec.ham-radio Subject: Re: What should a scheduler do? Message-ID: <1990Dec29.024545.28630@NCoast.ORG> Date: 29 Dec 90 02:45:45 GMT References: <1990Dec17.214336.8190@ni.umd.edu> <1990Dec28.021435.11795@quest.UUCP> Reply-To: allbery@ncoast.ORG.ORG (Brandon S. Allbery KB8JRR) Followup-To: comp.os.misc Organization: North Coast Computer Resources (ncoast) Lines: 33 As quoted from <1990Dec28.021435.11795@quest.UUCP> by ssb@quest.UUCP (Scott Sheldon Bertilson): +--------------- | I've hacked a little on a version of NOS that Anders Klemets ported | to System V UNIX. It uses shared memory and semaphores. Each > ... | overhead of synchronization using semaphores does a good job of | gobbling up substantially more than a 10 MHz 68010 (my AT&T 3B1). | I made a change to interlock using a test-and-set instruction | on some shared memory before trying to get a major semaphore..it | increased the efficiency of the package enough so that it | is reasonably snappy, but I've had problems with synchronization | not working properly, so I can't call it a success. +--------------- I'm working on a complete reimplementation using Streams for SVR3. It is based on raw Streams, not the NSL, so it should work on any System V that has Streams support --- and some that claim not to, like Xenix 2.3.x without the appropriate network package. (I'm doing this under Xenix 2.3.3.) Of course, this won't help on a 3B1, which is SVR1 in the kernel. (Actually, I'm still trying to decide how much I should do at the Streams level --- should I simply arrange for local sockets and use ordinary programs to do the real work, or put AX.25, NET/ROM, and TCP/IP in Streams modules and have the far end be selectable between a "bidirectional Streams pipe" and a real Streams tty driver? The problem with the latter is that it isn't particularly easy to implement something like NOS's "ax25 route add" command.) ++Brandon -- Me: Brandon S. Allbery VHF/UHF: KB8JRR on 220, 2m, 440 Internet: allbery@NCoast.ORG Packet: KB8JRR @ WA8BXN America OnLine: KB8JRR AMPR: KB8JRR.AmPR.ORG [44.70.4.88] uunet!usenet.ins.cwru.edu!ncoast!allbery Delphi: ALLBERY