Calling up the directory of files on a DOS machine is almost as bad as using a phone book without names.

Without it, if the real mode disk code (the Int 13h handler) was paged out, the virtual DOS machine would loop forever.

All 16-bit applications run by default in a single virtual DOS machine with shared memory space.

It already has a separate 1-2-3 product, Release 3.1, for more powerful DOS machines based on the 286, 386 and i486 microprocessors.

Then, one day, the Power Macintosh 6100/ 66 DOS machine arrived from Apple.

The program works on a plain DOS machine with 640 kilobytes of memory and three megabytes of free hard-disk space.

From there I jumped to DOS machines and the famous WordStar, once the most popular word processor of all time.

Each dumb terminal was connected to a session running up to 8 concurrent DOS virtual machines, all running on the host computer.

If a problem arose with a single DOS virtual machine it could be rebooted without an effect on other terminals attached.

I tried the so-called Professional Version, for DOS machines, the top of the line.