Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ames!killer!ssbn!carpet!bill From: bill@carpet.WLK.COM (Bill Kennedy) Newsgroups: comp.dcom.modems Subject: uucico and TB+ (summary, long) Message-ID: <120@carpet.WLK.COM> Date: 15 Jul 88 01:48:05 GMT Distribution: na Organization: W.L. Kennedy Jr. & Associates, Pipe Creek, TX Lines: 131 Some time ago I posted an inquiry regarding why the send and receive times were so different between my 12MHz '286 V/AT system and 16MHz '386 AT&T 386 UNIX system. First off let me thank everyone who replied. The best suggestions (get a smart serial card) I couldn't use because I have the internal version of the Trailblazer but I still might get one of those new fangled National chips with the FIFO's in it. Here is a summary of the replies. ----------------------------------------------------------------------- From: uunet!tis.llnl.gov!ames!telebit!rls Date: Fri Jul 8 08:36:37 1988 Yes you may want to turn off compression. It can cost up to 10-20% in terms of throughput. Another reason for the speed asymmetry that you're seeing may be the disk write time of the luggable (carpet?) machine. I would suggest trying a direct link between the machines (a hardwired RS-232 link) running at 9600 to see what the limiting factor is. You can also investigate this by watching the modem SD/RD lights and the disk access lights on each machine. It may give you some clues. Good luck! Regards, ============================================================================= Richard Siegel Phone: (415) 969-3800 Product Manager UUCP: {sun,uunet,ames,hoptoad}!telebit!rls Telebit Corporation ARPA: telebit!rls@ames.ARPA "We are, after all, professionals"...HST ============================================================================= [ I defeated compression and it helped a lot! ] ------------------------------------------------------------------------------ From uucp Fri Jul 8 19:30 CDT 1988 Date: Fri, 8 Jul 88 10:07:34 PDT From: ames!vsi1!lmb (Larry Blair) Your problems here are twofold. First, xmit figures are worthless, particularly for small files. The reason is that the time stats from uucp for xmit run from start-of-xmit to end-of-xmit of the last block, not waiting for the receiving system's "CY". Given the buffering in the 'blazer, the time is not real. For receive, the buffering doesn't reduce the time, so those figures are fairly accurate. I would strongly suspect that the low speed is related to slow disks and a large amount of overhead in creating files. I didn't notice what version of Unix you are running on your portable, but if it's an older SYS V, and the size of your core isn't very big, the overhead can be very large. Btw, the 'blazer's compression is only 12 bits. You can certainly increase your effective throughput by compressing before transmission. Even if your PCs can only do 12 bit, studies have shown that compressing on the host is a win. * * * O Larry Blair altnet----\ * * * O VICOM Systems Inc. pyramid!---\ * * * O 2520 Junction Ave. uunet!ubvax!vsi1!lmb * * * O San Jose, CA 95134 ames!------/ * * * O +1-408-432-8660 sun!------/ ------------------------------------------------------------------------ Date: Fri, 8 Jul 88 18:10:54 CDT From: james@bigtex.UUCP (James Van Artsdalen) Your TB+ buffers something like 30K of data internally. When you send a file, you start talking to the TB+ full speed, whatever the speed of the underlying link. When your uucico has "finished" sending out the file, it's really only finished sending to your TB+: the file hasn't necessarily all been sent to the remote machine, and not even necessarily from the remote TB+ to the remote uucico (there is a large receive buffer also). uucico has a very large overhead per transaction, and there are two transactions per mail message. Indeed these delays are quite a bit bigger than the time required to send many smaller mail messages. I would just plain ignore any claimed uucico statistics for anything less than 50K, but not only is uucico very inaccurate (1 sec accuracy, which could be 1K of data!), but the buffering makes hash of analysis too. -- James R. Van Artsdalen ...!ut-sally!utastro!bigtex!james "Live Free or Die" Home: 512-346-2444 Work: 328-0282; 110 Wild Basin Rd. Ste #230, Austin TX 78746 ----------------------------------------------------------------------------- Date: 9 Jul 88 00:30:17 EDT (Sat) From: charles@c3engr.UUCP (Charles Green) Have you noticed the modem throughput via the TD/RD lights as you send and receive? Offhand, I'd guess your 286 box just can't eat characters coming in that fast, and that you're seeing your RD light flicker off and on as the handshaking at your end slows things down. ---------------------------------------------------------------------------- Date: Fri Jul 8 21:27:18 1988 From: karl@ddsw1.UUCP (Karl Denninger) Organization: Macro Computer Solutions, Inc., Mundelein, IL In article <115@carpet.WLK.COM> you write: [ my stuff deleted ] Well, the '286 systems don't do so good -- we have a Usenet neighbor with one and can never hit more than about 6kbaud with him (this is Microport more than anything else)... On the other hand, I regularly receive and transmit at 1100cps with other sites (!). First, turn off the compress, especially if you're using compressed news batches. It doesn't help, and frequently hurts. Next, if you have a dumb sio board in the Uport/286 box, get a smart card. Third, find out how fast/slow your disk drives are. If they're really slow, you're gonna be sitting while the machine finds (stores) the next file.... and throughput drops. Your differences should greatly diminish.... -- Karl Denninger (ddsw1!karl) Data: (312) 566-8912, Voice: (312) 566-8910 Macro Computer Solutions, Inc. "Quality solutions at a fair price" --------------------------------------------------------------------------- Going through the file of responses I see that I had some things in there that weren't responses (which I omitted from the summary) and I see that all of the responses didn't get into the file, so apologies to those I missed and many many thanks to all who replied. -- Bill Kennedy Internet: bill@ssbn.WLK.COM Usenet: { killer | att | rutgers | uunet!bigtex }!ssbn!bill