The machine below is an IBM PC XT (Model 5160) with a 4.77Mhz 8088, 640K of memory, two diskette drives, a 10Mb hard disk, a serial port, and no video adapter: its only display is a DEC VT100 terminal connected to COM1 at 9600 baud. It boots the BASIC-DOS HD Terminal Only Demo diskette and runs a single session on the VT100, which starts on drive C:, the hard disk, with the BASIC-DOS source code, tests, and tools.
Wait a few seconds for the BASIC-DOS banner to appear on the VT100 (with no display, the boot sector’s Press a key to start... prompt isn’t visible, so it waits 2 seconds before booting the diskette), then type a command, such as DIR or PRINT "Hello from the VT100" (the VT100 has keyboard focus when the page loads; click its screen to give it focus again). The PC XT has no clock to keep the date and time, so use the DATE and TIME commands to set them. The PC has no screen of its own, so its diskette drive, hard disk, and Reset controls are below the VT100.
Any changes you make to the hard disk are lost when you leave the page, unless you first click Save HD to download the hard disk as an IMG file.
This demo is also available on an IBM PC with 64K and no hard disk.
The IBM PC XT doesn’t require a video adapter. SW1 switches 5 and 6 tell the BIOS which display is installed, and when both are ON (the setting an EGA uses, since it has its own BIOS), POST skips its video tests and initialization. The BIOS video functions still run, but with no display to update, the BIOS has nothing to show until BASIC-DOS opens COM1.
BASIC-DOS doesn’t require one either. The diskette’s CONFIG.SYS skips the VKD$ (video and keyboard) driver, opens the only console on COM1 with the COM driver’s VT100 terminal type, and starts the shell on drive C:, the hard disk, so all of its programs and files are available. Commands like CLS and LOCATE use VT100 escape sequences, the VT100’s DELETE key erases the previous character (like the PC’s BACKSPACE key), and XON/XOFF flow control is enabled, which the VT100 relies on whenever it falls behind (eg, while smooth scrolling).
The hard disk’s SAMPLES directory contains text copies of the BASIC samples from the IBM PC DOS 1.00 diskette, but most of them use graphics, so try the Color (with FPU) machine demo instead.
REM No video: one session on a VT100 connected to COM1, with its shell on the hard disk
SKIP=VKD$
BUFFERS=8
CON=COM1:9600,N,8,1,VT100
SHELL=C:COMMAND.COM PATH$="C:\;C:\EXT;C:\DEMOS;C:\SAMPLES;C:\TESTS;C:\TOOLS"
Copyright (c) 2020-2026 Jeff Parsons Released under MIT License