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), 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 is skipped as well (see CONFIG.SYS below), so there is no floating-point: numbers are 32-bit integers, and numeric functions like SQR are unavailable. The Color (with FPU) demo has an 8087, graphics, and all of COMMAND.COM, in 128K.
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 BASICDOS-360K-M64 diskette and runs a single 80-column session, with about 3K free for BASIC programs.
Use the MEM command to display current memory usage.
The BASICDOS-360K-M64 diskette’s CONFIG.SYS skips only the FPU$ (floating-point) and PIPE$ drivers, and asks for the minimum numbers of buffers, files, and sessions; the machine has no serial or parallel ports, mouse, or hard disk, and the drivers for those unload themselves when they find nothing to drive, so BASIC-DOS fits in 64K with a few K to spare. Since there isn’t room for all of COMMAND.COM, the loader loads only its core, which leaves out graphics, sound, and tokenized BAS files (see COMDATA for how a program declares its core), and COMMAND.COM reports Not enough memory for the statements that were left out. Unlike the other demos, COMMAND.COM doesn’t run HELLO.BAT here (its colors mean nothing on a monochrome display, and the first command after boot has about 1K less to work with than later ones, since the prompt’s own code and variable blocks haven’t been set up yet); type HELP for a list of commands, DIR to list the files on the diskette, and PRIMES.BAS to run the BASIC version of PRIMES.
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 they can’t run here; the Color (with FPU) demo runs them. The PC DOS 1.00 diskette in drive B: holds the original tokenized copies, which this configuration can’t load at all (Invalid file format).
REM 64K demonstration: one session with no FPU$ (floating-point) or PIPE$
REM drivers; the drivers for hardware this machine lacks (serial and
REM parallel ports, mouse, and hard disk) unload themselves
SKIP=FPU$,PIPE$
BUFFERS=2
FILES=8
SESSIONS=1
SHELL=COMMAND.COM PATH$="A:\;A:\BIN;A:\SAMPLES;A:\DEMOS"
Copyright (c) 2020-2026 Jeff Parsons Released under MIT License