With only 64K of memory, there isn’t room for all of COMMAND.COM, so BASIC-DOS loads only its core: the graphics statements (CIRCLE, DRAW, GET, LINE, PAINT, PRESET, PSET, and PUT), the sound statements (PLAY and SOUND), the file statements (eg, OPEN and CLOSE), less common statements and functions (eg, INKEY$, PEEK, RND, SCREEN, and TAB), and LOAD’s support for tokenized BAS files (like the originals on the PC DOS 1.00 diskette in drive B:) are left out, and using one of them reports Not enough memory. The FPU$ driver also unloads itself on a machine with 64K or less, so there is no floating-point: numbers are 32-bit integers, and numeric functions like SQR are unavailable.
The machine below is an IBM PC (Model 5150) with a 4.77Mhz 8088, 64K of memory, a Monochrome Display (appropriate for a configuration without graphics), and two diskette drives. It boots the BASIC-DOS Monochrome Demo diskette and runs a single 80-column console. Use the MEM command to display current memory usage.
This demo is also available on an IBM PC XT with 640K and a 10Mb hard disk.
The diskette’s SAMPLES directory contains text copies of the BASIC samples from the IBM PC DOS 1.00 diskette, but most of them use graphics (and some use floating-point), so try the Color Graphics machine demo instead.
REM 64K demonstration with one session and no PIPE$ driver
REM FPU$ and PIPE$ (at 64K) and drivers for missing hardware skip themselves
BUFFERS=2
SHELL=COMMAND.COM PATH$="A:\;A:\EXT;A:\DEMOS;A:\SAMPLES"
Copyright (c) 2020-2026 Jeff Parsons Released under MIT License