Ampl.exe.gz is a compressed MSDOS extended-memory Student Edition version of AMPL. It is a "current" (frequently updated) version of the AMPL.EXE that originally accompanied the AMPL book. As such, it is restricted to 300 variables and 300 constraints. See netlib's "ampl.info from ampl" for information about other platforms and unrestricted versions. See also the AMPL web site, http://www.ampl/com/ampl/ Ampl.exe requires an Intel 80386 or equivalent (e.g., i486). It was compiled by Symantec C/C++ version 6. It uses the DOSX 386 DOS Extender, which tries to work with whatever extended-memory driver your system's CONFIG.SYS file may provide. For example, Symantec reports that DOSX works with Microsoft's HIMEM.SYS, RAMDRIVE.SYS, SMARTDRV.SYS, with Microsoft Windows Versions 3.0 and 3.1 in Standard, Real, and Enhanced 386 modes, with Qualitas 386^MAX Version 5.0 and later (but not earlier), and with IBM's VDISK.SYS and Quarterdeck's QEMM memory manager. Watampl.exe.gz is similar to ampl.exe.gz, but was compiled by WATCOM C/C++32 version 10.6 (which works around the Pentium divide bug). It requires a helper program, DOS4GW.EXE (provided by WATCOM for use with programs compiled by WATCOM and available in compressed form as dos4gw.exe.gz), that provides extended-memory services. We solicit feedback on the relative merits of AMPL.EXE and WATAMPL.EXE. Both require at least a 386, and neither will run on all all configurations of such PCs. This is true of every compiler we have tried; such is the dreadful state of computing under MS-DOS and Microsoft Windows. Please send feedback to dmg@research.att.com (David M. Gay). Compression of .gz files is by gzip, source for which is available by ftp in prep.ai.mit.edu:/pub/gnu. As a convenience, gzip binaries for several systems (with names of the form system.executable) and source for the gzip used to compress the *.gz files is available for ftp from netlib directory gnu/gzip. In particular, if you copy gnu/gzip/dos.executable to an MSDOS machine (in binary mode), rename it gzip.exe, and rename ampl.exe.gz ampl.exz, then on the MSDOS machine you can recover ampl.exe by executing "gzip -dN ampl.exz". "gzip -d" also uncompresses .Z files. To use WATAMPL.EXE in a DOS window under MS Windows on a machine that lacks a math coprocessor, it is necessary to have WEMU387.386 on the machine, say in the Windows directory (normally C:\WINDOWS), and to add a line of the form device=C:\WINDOWS\WEMU387.386 to the SYSTEM.INI file in the Windows directory (normally C:\WINDOWS\SYSTEM.INI). WEMU387.386 is another program provided by WATCOM for use with programs compiled by WATCOM compilers; wemu387.386.gz is the result of using gzip to compress WEMU387.386.