Xref: utzoo comp.sys.amiga.hardware:3890 comp.sys.amiga.tech:14896 comp.sys.amiga:68011 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!twg.com!david From: david@twg.com (David S. Herron) Newsgroups: comp.sys.amiga.hardware,comp.sys.amiga.tech,comp.sys.amiga Subject: Re: PLEXUS UNIX BOX and Amiga Message-ID: <8032@gollum.twg.com> Date: 6 Oct 90 01:44:58 GMT References: <1990Oct3.042810.17799@caen.engin.umich.edu> <1990Oct3.043213.18022@caen.engin.umich.edu> Reply-To: david@twg.com (David S. Herron) Followup-To: comp.sys.amiga.hardware Distribution: na Organization: The Wollongong Group, Palo Alto, CA Lines: 56 In article <1990Oct3.043213.18022@caen.engin.umich.edu> gilgalad@caen.engin.umich.edu (Ralph Seguin) writes: >Hi. I am about to acquire a PLEXUS 68000 based UNIX box running >Sys V.2 (yech, I know 8-). I have several questions. >1: Can I get something akin to DNET to compile on this beast? Not very likely .. the reason DNET requires sockets is so that it can avoid the "blocking" (i.e. hang-until-a-character-arrives) that normally happens on Unix. There normally isn't a way to specify that an I/O channel is able to do asynchronous reads or writes in Unix .. arguably a lack in its design. The way select() helps is that it lets the program check the port without hanging, or to hang for a little while, or to return when *any* I/O descriptor has characters or any reasonable combination of the above. System V has never had this, except through add-in packages from various vendors (ahem) add-in TCP/IP packages :-). System V r4 will (I think, haven't read the docs on it yet) have a socket interface in the native system. But that's neither here nor there .. SysVr2 simply didn't have anything similar. In r3+streams you have this system call which looks promising: poll(). But it only works on a "stream", and doesn't work on a real tty device even though the tty drivers had become streams based. The interface at the /dev/ttynn level had gotten the streams-isms stripped away, I suppose. Sigh.. The closest you get with r2 is to set the VTIM type parameters using stty (or ioctl() if you're speaking C at the OS). >2: Can I get an ethernet board for it? mebbe tho it might be a bit hard to find one since that machine probably isn't in production ... >3: It has 8 serial ports, so I'm hoping to get SLIP on it. Plan on porting TCP/IP on your own. If'n you do port it on your own you can maybe shove a real select() into it. On the other hand I've read through the source for TWG/TCP for 7300/3b1's (a SysVr2 box based on 68010, should be some similarity to your Plexus) .. All the code for doing select() on a tty is commented out -- I haven't read closely enough to see *why* but I suspect that some niggling detail in the kernel architecture on SysV doesn't support this. I would suggest working back and forth between Bach's book on SysV internals and Karels book on 4.3BSD internals ;-). Hope this helps ... [response is in public since I've seen other similar queries in the past] David -- <- David Herron, an MMDF & WIN/MHS guy, <- Formerly: David Herron -- NonResident E-Mail Hack <- <- Remember: On System V it's "tar xovf", not "tar xvf"!