The First Computer Virus of Bob Thomas Explained: Everything You Need to Know

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The First Computer Virus of Bob Thomas Explained: Everything You Need to Know

First Computer Virus History

The First Computer Virus, Creeper, was named after a Scooby-Doo cartoon show character. Creeper was written in 1971 by BBN computer programmer Bob Thomas. BBN, Bold, Beranek, and Newman, now Raytheon BBN Technologies, developed packet switching networks for ARPANET.

ARPANET was the internet’s forerunner launched in December 1969. As an Acronym for Advanced Research Projects Agency Network, ARPANET was originally established by the United States Department of Defense. It is also one of the first networks to use the TCP/IP protocol suite.

Quick Facts

Bob Thomas
Original Use
A security test to determine the possibility of a self-replicating program.

From history, Thomas created the first computer worm as an experimental self-replicating program. The experiment had zero malicious, harmful, or damaging intent, but to illustrate a mobile application’s working principle. However, the virus corrupted the Digital Equipment Corporation’s, DEC PDP-10 mainframe computers without any prior plan, messing up their connected teletype computer screens, displaying the message, “I’m the creeper, catch me if you can!” These DEC PDP-10 mainframe computers operated on the TENEX operating system. Although originally designed for DEC PDP-10 by BBN in 1969, TENEX later became the basis for DEC TOPS-20 operating system.

The  First Computer Virus of Bob Thomas affected mainframe computers operating on the TENEX operating system.
The TENEX operating system

While the Creeper virus corrupted systems, it isn’t considered malware, unlike other present-day computer viruses. This could be because of the limited damage it causes: the First Computer Virus only displays a message on computer screens, nothing more. The Creeper virus doesn’t steal or destroy data, cause the inoperability of mainframe computers, or demand a ransom. It only displays a message.

The First Computer Virus: How It Worked

Undoubtedly, the Creeper virus’s message is panic-inducing – history has it that several mainframe computer users were scared and annoyed due to the virus’ effects; as mentioned earlier, that wasn’t the original intent of Thomas, the creator. Thomas’ initial goal was to determine the possibility of developing a program that could spread between computers. Although he “almost” achieved that, the result was a virus, the Creeper virus.

The Creeper virus works by causing computers to print a file, then stop abruptly, find another Tenex system, open a connection, and download and transfer itself alongside its files, external states, etc. to the other system, and then start running on the new system, displaying its default message, “I’m the creeper, catch me if you can!”.

The program rarely, if ever, actually replicated itself; instead, it shuffles systems, attempting to remove itself from previous systems as it propagated forward. Hence, Creeper didn’t install multiple instances of itself on several targets; it actually moseyed around a network. The techniques developed in Creeper were later used in the Multi-computer Route Oriented Simulation System, McROSS, an air traffic simulator, to allow parts of the simulation to move across the network).

Although, compared to the present computer worms, the download and transfer actions of the Creeper virus may be ultra-simple. However, in 1971, it wasn’t: it was the first demonstration that applications can automatically move from a computer to another. While present-day computer viruses are damaging, the Creeper virus was, at most, annoying. A few technical users also claimed that the virus crowded out other computer programs.

The First Computer Virus: Historical Significance

The exact damaging extent of the Creeper virus – that’s if it causes any damage at all – is grossly unknown. While some sources confirm that it typically just annoys users, some say the virus’ download and replication often crowd out other computer programs. While this may be true, the extent of such effects wasn’t specified.

The First Computer worm resulted in a series of further research on how to curb its effect. Thomas’ colleague, Ray Tomlinson, also created another version of the Creeper, the Reaper Program, that moves through the internet and replicates itself, finding copies of Creeper and logging them out. Ray’s version was somewhat an enhanced version of Thomas’.

In essence, Ray created the Reaper Program to complement the Creeper virus. Therefore, if the Creeper was the world’s first computer virus, the Reaper is understandably the first anti-virus program.

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