Larry Carroll <LARRY@JPL-VLSI.ARPA> (12/29/84)
You must have been told wrong. The purpose of RatFor is to allow you to write C-like code which is translated into ForTran source for compilation by a ForTran compiler. It's a public domain program for those with no (or a terrible) C compiler who do have a ForTran compiler. The ForTran source produced by RatFor (and other such interpreters) is pretty ugly and introduces a 5-10% speed penalty. Also, the ForTran compilers occasionally do some erroneous optimization of RatFor'd code. These errors are pretty rare, and the speed penalty is generally made up for by the excellence of ForTran compilers. The ugly ForTran is looked at only when you're looking at a hex/octal dump to find the exact location and nature of an error. Then you change the RatFor code, not the ForTran code. I've a question of my own about Unix/Xenix on the AT. Benchmarks have shown only a 2-3 times speed advantage of the AT over the PC. If you use a multi-user OS, doesn't the overhead pretty much eat up that advantage, giving you in effect only PC capability? Larry @ jpl-vlsi ------
tomk@ur-laser.uucp (Tom Kessler) (12/29/84)
>I've a question of my own about Unix/Xenix on the AT. Benchmarks have >shown only a 2-3 times speed advantage of the AT over the PC. If you use >a multi-user OS, doesn't the overhead pretty much eat up that advantage, >giving you in effect only PC capability? I've been told by people who have used Unix/Xenix on the AT (and seen the source) that the version of Xenix on the AT is just the 8086 version of Xenix with the 8286 in the AT running in 8086 compatibility mode with a few minor improvements. Hence it is not very surprising that the AT shows only a 2-3 times increase. One friend of mine said "You mean you're going to give this to paying customers?" when he first saw the Xenix 8286 Kernel. When you are running multiuser your probably better off using a PC. -- -------------------------- Tom Kessler {allegra |seismo }!rochester!ur-laser!tomk Laboratory for Laser Energetics Phone: (716)- 275 - 3786 250 East River Road 275 - 3194 Rochester, New York 14623
dan@digi-g.UUCP (Dan Messinger) (01/04/85)
>>I've a question of my own about Unix/Xenix on the AT. Benchmarks have >>shown only a 2-3 times speed advantage of the AT over the PC. If you use >>a multi-user OS, doesn't the overhead pretty much eat up that advantage, >>giving you in effect only PC capability? Off hand, this may seem obviously true, but in practice, (when MS-DOS is the single user system), I have discovered the opposite. I haven't tried any benchmarks on the AT, but I did do some on a PC running DOS and Venix. I was quite surprised to discover the Venix gave me better overall performance than MS-DOS did. The difference was not significant in value, just in direction. The most significant difference was in system request performance. Dan Messinger ihnp4!umn-cs!digi-g!dan
rabson@harvard.ARPA (David Rabson) (01/16/85)
Would anyone like to post a review article to the net dealing with {V,U,X}nix's
for personal (<$4000) computers?