Editing Time-sharing (section)

===Security===
Time-sharing was the first time that multiple [[Process (computing)|processes]], owned by different users, were running on a single machine, and these processes could interfere with one another.<ref name=Silberschatz2010>{{cite book|last1=Silberschatz |first1=Abraham| last2=Galvin |first2=Peter|last3=Gagne |first3=Greg|title=Operating system concepts|year=2010|publisher= Wiley & Sons | location = Hoboken, N.J. | isbn = 978-0-470-23399-3 | edition = 8th | page = 591}}</ref> For example, one process might alter [[shared resource]]s which another process relied on, such as a variable stored in memory. When only one user was using the system, this would result in possibly wrong output - but with multiple users, this might mean that other users got to see information they were not meant to see.

To prevent this from happening, an operating system needed to enforce a set of policies that determined which [[Privilege (computing)|privileges]] each process had. For example, the operating system might deny access to a certain variable by a certain process.

The first international conference on computer security in London in 1971 was primarily driven by the time-sharing industry and its customers.<ref>{{cite thesis |last1=O'Neill |first1=Judy Elizabeth |title=The Evolution of Interactive Computing Through Time-sharing and Networking |date=1992 |oclc=1011609244 }}{{pn|date=February 2024}}</ref>

Time-sharing in the form of [[Shell account|shell accounts]] has been considered a risk.<ref>{{cite journal |last1=Toxen |first1=Bob |title=The Seven Deadly Sins of Linux Security: Avoid these common security risks like the devil. |journal=Queue |date=May 2007 |volume=5 |issue=4 |pages=38–47 |doi=10.1145/1255421.1255423 |doi-access=free |quote=Most recent vulnerabilities are not directly exploitable remotely on most systems. This means that most systems are not at risk for remote attack from the Internet. Many of the vulnerabilities may be taken advantage of by someone with a regular shell account on the system. }}</ref>