Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!eagle!harpo!ihnp4!inuxc!pur-ee!uiucdcs!uiucuxc!beaucham From: beaucham@uiucuxc.UUCP Newsgroups: net.micro.16k Subject: Re: LMC 16032: Any - (nf) Message-ID: <6232@uiucdcs.UUCP> Date: Sat, 17-Mar-84 22:48:17 EST Article-I.D.: uiucdcs.6232 Posted: Sat Mar 17 22:48:17 1984 Date-Received: Mon, 19-Mar-84 06:56:18 EST Lines: 37 #R:hao:-86400:uiucuxc:25800001:000:2645 uiucuxc!beaucham Mar 17 14:07:00 1984 I visited LMC in Chicago yesterday and was very impressed with their machine, but had some reservations. We brought with us an 8" floppy created by tar on our vax780 holding three short source programs, two f77 and one c; the floppy was in IBM standard SS/SD format. They copied the 8" to a 5.25", inserted this into the MegaMicro, and promptly installed the three files. (I don't know what they used to make the copy.) All three programs compiled without a hitch. At first, one of the two ftn programs would not execute, and we thought at first it was due to incorrect compilation of a COMPLEX function; however, it turned out to be a bad FPU chip, which when replaced resulted in perfect execution of the program. I was interested in benchmarking ftn and c in comparison to our vax780. The results using %time ~cbin~ were 13.1u + 0.5s = 13.6 vax780 56.7u + 3.1s = 59.8 LMC and after LMC engineer Robert Farber performed some optimization on the c code and the resulting assembly (in anticipation of an improved c compiler) the later result improved to 42.0u + 2.7s = 44.7 LMC So on c execution the ratio seems to be about 3 or 4 to 1. With Fortran things are not so impressive. For one program the comparison was 0.3u + 0.1s = 0.4 vax780; 2.0u + 6.5s = 9.0 LMC >> 20 to 1 andtheother .5u + 0.3s = 0.8 vax780; 2.5u + 5.7s = 8.2 LMC >> 10 to 1. Unfortunately, we did not time the ftn & c compilations, but since we were the only ones on the LMC i would estimate a 20 to 1 ratio to the vax. In summary it seems that they are capable of 4 to 1 ratios to the vax with c, but for ftn are they any faster than an IBM pc with an 8087? The package looks very nice and compact. The unit they demoed had the dumb serial interface but they strongly recommend the smart one. The box will hold 15 multibus cards;i wonder if the fan could handle 15 cards.However, with about six cards in it, it was running very cool and surprisingly quiet (about 60 DBA). One fear i have concerns the sensitivity of the National chips.Evidentally, the supply must be adjusted with +-.1 volt for proper operation andthe chips must be selected to have identical best running voltages. During our demo we had one crash and an engineer had to adjust the voltage for best operation. They claimed this particular unit was hastily put together because their good units were out for field demos. i think the LMC will handle 4 users without problem. I too am looking for competitive machines. James Beauchamp, music bldg., uiuc, urbana, IL 61801 (217) 344-3307/333-1089