UNIX PC Demonstrations


This image was created for the 3b1 UnixPC in the VCF museum. The image is of a 6085 Miniscribe drive so is 67 MB. It has 39% free space.
mfm_emu image file for my mfm disk emulator
Raw sector image of disk.   Works with FreeBee emulator.   Tools are available for working with image.
Tar file of contents   and browsable files

The image has accounts tutor, install, demo, games, and root. Accounts don't have passwords. For the VCF image the VCF UnixPC is running install and root do have passwords and the DOS-73 board software is installed but not configured.

Shutting down

Log in to root and type shutdown. Wait until you see Ready to power off or reset the machine before turning off power.

Installed software

A number of software packages were installed through the normal install mechanism. Bash, emacs, gcc, newer bwbasic, date-y2k, kermit, and various useful utilities were also installed. See contents of /usr/local/bin. date-y2k allows you to set the clock to dates past 2000. Get your use in before 2038. Also in /usr/bin is sdump and sprint for writing screen to bmp file and engine which animates an engine.

The Unix is based on System V Release 2. It will seem familiar to current Unix users but will be missing a lot of options and commands you are used to. Also file names are limited to 14 characters.

See my setup and usage notes from when I was making this image. They were notes to myself so somewhat cryptic.

Multi user

I have configured the console to allow 3 logins. If you use shift or control-suspend and resume keys you can switch between the 3 logins. The image also has the rear tty0 serial port enabled for logins at 9600 baud. It looks like the 1200 baud modem is also enabled for login. I have not tested.

General operation notes

tutor account

This account shows off the UnixPC GUI.

GUI operation

At the console you can use the mouse to select one of the menu choices. The clicking on the X at the bottom left of a window closes the window. Under FreeBee F10 to make UnixPC cursor follow host cursor or release it. F9 is suspend key.

At the UnixPC console the keyboard has Return and Enter key. Choosing items from the GUI menu uses the enter key or mouse. Choosing them over a serial console or in the FreeBee emulator can be done with control-J or on my computer alt-enter. Return moves to next menu item. More serial equivalents for special keys

Interesting programs

Demonstration Programs has a bunch of graphical slide shows of graphics, pictures, and marketing material you can select. These continuously update.

A couple on screen calculators are available.

Telephone starts the integrated telephone control. I haven't set anything up in it yet. Since it's from AT&T the computer had integrated modem and support software such contact list for dialing numbers. I haven't investigated this area much.

The VCALC spreadsheet is available. To exit VCALC type /q

For VCF UnixPC which has the DOS-73 board there are options for working with it. FreeBee doesn't emulate this board. I have not configured the DOS-73 PC emulator software in the VCF image.

Filecabinet is the file system browser. Under it is demo menu which allows starting demo of Electronic mail, AT&T word processor, dBASE III, Multiplan, and SUPERcomp 20. Control-C will stop the demo. Clicking outside the menu window will close it. The X doesn't seem to work.
Under Filecabinet practice are some files you can open. Example word document starts Microsoft Word with promotional document. Cancel key (Esc c n on FreeBee) and Q exits. Example sample file and windows sample file gives some information on the UnixPC.

demo account

This is a ksh account. You can recall previous commands with esc k. Some other vi key sequences work preceded by esc. The fc command is another way of interacting with command history. Whence is similar to bash which. I added .kshrc my wife used when the 3b1 was her home computer to this account. It gives you pushd and popd commands.

This account has various programs you can demonstrate from the shell. It also has a .kermrc and .mykermrc to configure kermit for reasonable performance.

Hello World and other programs.

I have hello word programs in C, BASIC, and Logo. Each prints 10 times the string Hello World Your Name. I was expecting that the name would be edited to change the name to the visitor to show your favorite editor.


cd to the directory C. Edit helloworld.c, type make, then run helloworld. A larger C program is in sprintfile. You can demonstrate building with make clean, make. This is the program to dump the screen to a BMP file. The makefile builds with the native C compiler cc which is a plain K&R compiler. You can manually build with gcc (1.42) which supports prototypes.


cd to the directory basic. Edit helloworld.bas either externally or in BASIC. Run with bwbasic helloworld.bas or start bwbasic and load "helloworld.bas".

To stop a running program type control-C. To exit BASIC type quit.

Also available to run are UT-Trek.basic which prints instructions and startrek.bas. bwbasic is somewhat slow. startrek.bas is a smaller program that loads faster.

The subdirectory GAMES has a number of games that came with Bywater BASIC. I have not looked at them to know which are interesting.


cd to the directory logo. Either edit the file helloworld.lg then logo helloworld or type logo then edit "helloworld.
To stop a running program type control-C. To exit Logo type bye.

There are two simple Logo demonstration programs. logo star will draw a star and logo runtree will draw a tree repeatedly. It can be used as a program to leave running so the machine will be doing something.


vi and emacs are installed. To quit vi :q. I'm vi person so short info on editing with it
vi file
h - move left
l - move right
j - move down
k - move up
cw - change word at cursor. Type new contents, esc to stop
x - delete character under cursor
i - insert text at cursor. Type new contents, esc to stop
:q! quit ignoring changes
:wq write file and quit
To quit emacs control-X control-C. Emacs has hanoi and doctor to show power of its lisp language. esc-x then hanoi or doctor to start. Control-X to stop hanoi then normal exit. Normal exit works for doctor.

games account

It puts up a menu to allow playing
dungeon (zork)
tetrix (tetris)
bugs (space invaders-ish, graphics). q exits
rocks (asteroids-ish, line drawing characters)

More games are in /usr/games.

Man pages

For the UnixPC the man pages were paper manuals. Man pages for the operating system were not available on the machine. Disk space was limited especially for the 7300 model. Frequently software installed had man pages. The UnixPC did have a man command but you needed to specify the file you wished to be processed. My wife created a man script that was more like bigger systems where man command displayed the man page for a command and man -k word searched the man page index for the word. I have installed that on the machine. All local man pages are in /usr/man. Other copes may still exist in different locations.

Other future demos

There are more programs on the machine which I haven't described. Have fun poking around.

Demos could be done for the communications capability. The UnixPC had an app store called The STORE! that was done with dial up uucp. It also has email capability. It did have a SLIP package with telnet, ftp, SMTP which isn't currently installed. It does have kermit installed. An Ethernet card was available but the board is very rare. Also had StarLAN board that is equally rare.


The image has drivers for the expansion serial card. If you don't have the hardware removing that software can speed up boot. Use the install account administration -> Software Setup -> remove installed software to remove RS-232 Expansion 3.51. The DOS-73 software can't be uninstalled that way. I ran /usr/installed/\<00101759.un and /usr/installed/\<001012585.un to remove it from the image. I also removed the /u/demo/dos* and /u/demo/8S_dos73-diag. The directory /u/demo/old has files left over from my build and can be deleted. Some of the files in /usr/src have been installed so source no longer needed. Others are on the machine but have not been built.

Under FreeBee the screen saver is probably not useful. You can turn it off Login as Install, Preferences > Office > Turn screen off after X minutes Set to 0 then OK.


Pictures of the mod to allow larger and more disks in one of the museum 3b1's.
3b1 drive recovery with my MFM reader/emulator

Feel free to contact me, David Gesswein djg@pdp8online.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with.  I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation. 

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