Compatible Time-Sharing System

computer science

Also known as: CTSS

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Last updated

June 24, 2026

Quick Summary

The Compatible Time-Sharing System (CTSS) was a pioneering computer system developed in the early 1960s at the Massachusetts Institute of Technology (MIT). It allowed multiple users to interact with a single, powerful central processing unit (CPU) nearly simultaneously. This was achieved by utilizing the CPU's speed to process user requests in rapid succession, creating the illusion of instantaneous response for each user, even while the computer was handling other tasks. CTSS was a foundational step in the development of interactive computing and computer networking, enabling more efficient use of expensive computing resources.123

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computer
Time-sharing from Project MAC to UNIX
…Corbato was working on, called Compatible Time-Sharing System, or CTSS. Still, Corbato was waiting for the appropriate technology to build that system. It was clear that electromechanical and vacuum tube technologies would not be adequate for the computational demands that time-sharing would place on the machines. Fast, transistor-based computers were…
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…Corbato was working on, called Compatible Time-Sharing System, or CTSS. Still, Corbato was waiting for the appropriate technology to build that system. It was clear that electromechanical and vacuum tube technologies would not be adequate for the computational demands that time-sharing would place on the machines. Fast, transistor-based computers were…
Read More

instant messaging
…a formal IM was the Compatible Time-Sharing System (CTSS), which originated in 1961 at the Computation Center at the Massachusetts Institute of Technology (MIT). CTSS was housed in a large mainframe. Users connected to the mainframe through remote dial-up terminals to send messages back and forth to one another and…
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…a formal IM was the Compatible Time-Sharing System (CTSS), which originated in 1961 at the Computation Center at the Massachusetts Institute of Technology (MIT). CTSS was housed in a large mainframe. Users connected to the mainframe through remote dial-up terminals to send messages back and forth to one another and…
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Fernando Corbató
The project built on the Compatible Time-Sharing System (CTSS), software that Corbató had created in 1961 at MIT. Project Mac developed the necessary hardware to implement CTSS. This time-sharing system went online in 1963 and was used at many locations around the world until newer hardware designs arrived in 2000.…
Read More
The project built on the Compatible Time-Sharing System (CTSS), software that Corbató had created in 1961 at MIT. Project Mac developed the necessary hardware to implement CTSS. This time-sharing system went online in 1963 and was used at many locations around the world until newer hardware designs arrived in 2000.…
Read More