UNIX v4

Authentic Computing Experience from 1973

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UNIX v4 (1973)

PDP-11/45

ℹī¸ Help & Info

📜 About UNIX v4

Released November 1973 - the first UNIX written in C, making it portable across hardware platforms.

This is the only known copy, recovered in 2025 from a magnetic tape discovered at the University of Utah after 52 years.

Running on an emulated PDP-11/45 minicomputer, the same hardware used at Bell Labs.

Sources: squoze.net | tape recovery story

💝 Feedback & Contact: Check out our guestbook below, or send private feedback to [email protected]

🔑 Essential Commands

  • ls List files
  • cat file View contents
  • chdir dir Change directory
  • ed file Edit text file
  • cc file.c Compile C program
  • date Show system date
  • du Disk usage
  • wc file Count lines/words
  • ctrl+\ Stop running programs (interrupt)

⚠ī¸ Important Notes

â€ĸ Backspace doesn't work!
  Press # to delete char, @ for line

â€ĸ Use chdir not cd

â€ĸ No man pages (that's v5+)

â€ĸ Sessions are temporary (10min timeout if left idle) and ephemeral (state is not saved between sessions and reset on page reload)

â€ĸ Authentic 1973 behavior - expect quirks!

🧭 Things to Explore

Directories:

  • /demo - C programs to compile
  • /usr/games - Vintage games
  • /usr/source - Unix kernel source
  • /bin - Available commands

Quick Start:

chdir /demo
cc hello.c
./a.out

đŸ’ģ Demo Programs

Pre-installed in /demo:

  • hello.c - Hello World
  • primes.c - Prime finder
  • guess.c - Number guessing game
  • fib.c - Fibonacci sequence

📊 Server Statistics

Active Sessions
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All Time Sessions
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📝 Guestbook

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📜 Attributions & Acknowledgements

📜 UNIX v4 License

The UNIX v4 software and disk image are licensed under the Caldera Ancient UNIX License.

Copyright Š Caldera International Inc. 2001-2002. All rights reserved.

This product includes software developed or owned by Caldera International, Inc.

UNIX v4 is provided for educational and historical purposes. No warranty. Use at your own risk.

â„ĸī¸ Trademarks

UNIX is a registered trademark of The Open Group in the US and other countries.

This website is not affiliated with or endorsed by Bell Labs, AT&T, The Open Group, or any other trademark holders.

đŸĸ This Application

The website design, user interface, and integration platform are original works created by:

Copyright Š 2025 Squiz Software Pty Ltd - All Rights Reserved

This includes the visual design, theming, web interface, and custom demo programs.