On Mon, 31 Dec 2007 13:16:14 -0700 Phil Meyer <pmeyer@xxxxxxxxxxxxxxxx> wrote: > If you are having students compile stuff, then you need to stick to the > lowest common denominator (32bit) or else they cannot use those compiled > programs elsewhere. This is a bit of a niche issue, but it may be important with regard to certain applications. You can use DOSEMU (http://www.dosemu.org) to run old (and new) DOS programs on Linux. I wrote, support and maintain what has become a fair-sized suite of special-purpose programs for a particular industry. For various reasons, the programs are written in PowerBASIC/DOS and run on Linux application servers under DOSEMU. Linux/x86_64 runs DOS programs under DOSEMU approximately 13 times slower than they run on Linux/i386. This is not as big of an issue as it may initially appear, because even 13 times slower on a 3+GHZ computer is faster than computers were running in back in the days when DOS was king of the hill. For an interesting description of the reason this happens, I highly recommend this article: http://thebs413.blogspot.com/2005/10/what-is-x86-64-long-mode-memory-model.html In short, running i386 Linux allows your CPU to use a “Virtual86” mode, while x86_64 Linux requires that the whole thing be emulated in software which obviously takes more horsepower and therefore runs more slowly My conclusion is that if you want to run the occasional DOS program on Linux, then x86_64 may be worth using depending on what other native Linux programs you normally use and require. On the other hand, if you are setting up a server for the main purpose of running DOS programs on it (like I do) then i386 (32-bit) Linux is the way to go, simply because a 13 times increase in speed is obviously worth having. -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com
