DoubleDOS 2.x

DoubleDOS is a simple and easy to use multitasking tool for DOS. It can preemptively run up to two DOS programs at a time. Its main advantage is that it requires very little RAM overhead compared to other multitasking or task switching environments. Because DOS programs can and usually do bypass OS calls, many programs must be "patched" in order to work.

DoubleDOS is a minimalist program, but if you only needed to do two things at once, then this would have been a good choice. Reportedly, the first version may have worked with DOS 1.x.

Screenshots

Release notes

This version is very picky about what version of DOS it is running on. It only supports IBM PC-DOS 2.0 and IBM PC-DOS 2.1.

Important: This version has an unprotect applied to it. The software is normally copy protected.

Wanted: Kryoflux/SCP/Transcopy dump of the original media.

Archive includes one 5.25" 160k floppy disk image.

Installation instructions

It seems to crash under any earlier version of DOS than IBM PC-DOS 2.10. I suspect only the DOS 2.10 support code was patched to bypass the copy protection.