Cyberdyne Systems is the corporation that created Skynet in the original, unaltered timeline.
The Terminator and Terminator 2: Judgment Day
Cyberdyne is initially a benign manufacturing corporation at 18144 El Camino Real, Sunnyvale, California. Its products are unknown, but from the equipment in its factory and its high tech-sounding name, it seems possible that Cyberdyne might have been some sort of smaller parts producer for larger manufacturers of high tech equipment.
A Series 800 Terminator, which is sent from the future and designed to kill humans, is crushed in one of the hydraulic presses in Cyberdyne's factory. Thus, the company obtains the machine's wreckage, including its CPU chip and an arm. 
After reverse engineering the Terminator's remains, Cyberdyne reverse engineers its CPU and creates a powerful new microprocessor for weapons systems, becoming a major contractor for the US military.
Cyberdyne eventually develops Skynet, a network of supercomputers that employ artificial intelligence in order to replace human beings as commercial and military aircraft pilots, and for the control of other military systems, including nuclear missiles. The system goes online on August 4, 1997. On August 29, 1997, Skynet becomes self-aware. In a panic, humans attempt to shut it down, but Skynet retaliates by launching a nuclear attack against Russia, knowing that the Russian counterattack will eliminate its enemies in the United States, initiating an indeterminately long period of global warfare. The battle pits humans against machines, which develop ever-increasing capabilities. The event is later known as Judgment Day.
In an effort to prevent Judgment Day from occurring, Cyberdyne's headquarters are destroyed by a group of saboteurs in 1995: John Connor, future leader of the human resistance, his mother Sarah Connor, and a second Series 800 Terminator that traveled back in time, with Miles Dyson, Cyberdyne's lead researcher, assisting them in this endeavor.
T2 3-D: Battle Across Time timeline
Terminator 3: Rise of the Machines timeline
Despite the destruction of Cyberdyne's headquarters, the timeline is only slightly altered: after the destruction of the company's headquarters, Cyberdyne Systems patents are obtained by the U.S. Government, with another technological corporation Cyber Research Systems. Skynet continues to be developed by the company for SAC-NORAD, and ultimately, Judgment Day occurs, just at a later date than it would have originally.
Terminator Salvation timeline
It is revealed that Cyberdyne is still in existence as of 2003. In 2003, Dr. Serena Kogan convinces Marcus Wright to sign a paper to donate his body to Project Angel, a project of the genetics division of Cyberdyne Systems.
Terminator: The Sarah Connor Chronicles timeline
Shortly after being hacked, John Henry was able to discern that his systems had been infiltrated by another Artificial Intelligence based on the code used in his own creation. An analysis of the code revealed that the code was created by Cyberdyne Systems R&D Specialist Miles Dyson before his death.
Machines manufactured by Cyberdyne Systems
- Cyberdyne Systems Series 70
- Cyberdyne Systems Series 600
- Cyberdyne Systems Series 700 (presumably)
- Cyberdyne Systems Series 800
- Cyberdyne Systems Series 1000
- Cyberdyne Systems T-1000000 (presumably)
- Harvester (presumably)
- Hydrobot (presumably)
- Moto-Terminator (presumably)
- Sidewinder (presumably)
- Snowminator (presumably)
- Skynet Express (presumably)
- Transport (presumably)
- In NOW Comics The Terminator and Terminator: The Burning Earth, Cyberdyne Systems is called Technodyne Systems. In Terminator: All My Futures Past, it is called Cyderdyne again.
- In the original timeline, at some point after the Judgment Day, Cyberdyne Systems creates the Series 600, Series 800 and Series 1000 Terminators under the control of Skynet.
- It can be assumed that Cyberdyne continued its work on AI despite the loss of its corporate headquarters in 1995. Its work continued until it was sold to the USAF. Later, it was either restructured into Cyber Research Systems or was under the administration of the Air Force's already existing division called CRS.
- However, none of this explains why Cyberdyne logos are still being used by Skynet in 2018, but then nothing can really explain why a self-aware AI uses the logos of a company that no longer exists by that year. The use of those logos in 2018 says nothing about when Cyberdyne originally ceased to exist.
Behind the Scenes
- In the first five drafts of the script of The Terminator, Kyle Reese refers to the company as Cyber Dynamics. Cyberdyne is likely derived or a portmanteau of the words "Cyber Dynamics".
- Universal Studios Orlando, Universal Studios Hollywood and Universal Studios Japan have full size Cyberdyne Corporation lobbies for their ride T2 3-D: Battle Across Time where visitors are treated to a PR film by Cyberdyne extolling the virtues of the Skynet system and Cyberdyne's other "security" and "consumer" oriented innovations and are often harassed by an impatient company hostess named Kimberly Duncan.
- Cyberdyne, Inc is also the name of a real life Japanese company which manufactures robotic suits.
- Kyle Reese: (While being interviewed by Dr. Silberman) ...a defense network computer, a modified Series 4800, built for SAC-NORAD by Cyber Dynamics.
- The Terminator original script
- The Terminator (In a deleted scene.)
- Terminator 2: Judgment Day
- T2 3-D: Battle Across Time
- Terminator 3: Rise of the Machines (Mentioned only)
- Terminator Salvation
- Terminator: All My Future's Past (Mentioned only)
- The Terminator (NOW Comics) (Mentioned only)
- Terminator: The Burning Earth (Mentioned only)
- The Terminator: Tempest
- The Terminator: Secondary Objectives
- The Terminator: The Enemy Within
- Terminator 2: Judgment Day - Cybernetic Dawn (Mentioned only)
- Terminator 2: Judgment Day - Nuclear Twilight (Mentioned only)
- Video games
- Robocop versus The Terminator (Mentioned only)
- Television series
- Terminator: The Sarah Connor Chronicles (Mentioned only)
- ↑ Address listed in the phone book in the deleted scene from The Terminator
- ↑ The information in this section is from several deleted scene of the film The Terminator
- ↑ According to one of the internet news pages that Marcus accesses in the Skynet Central.
- ↑ This is consistent with the USAF being revealed as the organization that finishes Skynet's development in Terminator 3: Rise of the Machines. It should be noted that Terminator 3: Rise of the Machine film itself doesn't mentioned if Cyberdyne was destroyed.
- ↑ Official Script, 5th Draft at IMSDB
- ↑ Robot Suit HAL®, Cyberdyne, Inc