Process isolation in computer programming is the segregation of different software processes to prevent them from accessing memory space they do not own. The concept of process isolation helps to improve operating system security by providing different privilege levels to certain programs and restricting the memory those programs can use. Although there are many implementations of process isolation, it is frequently used in web browsers to separate multiple tabs and to protect the core browser itself should a process fail. It can be hardware based or software based, but both serve the same purpose of limiting access to system resources and keeping programs isolated to their own virtual address space.
The basic functioning of process isolation involves assigning a process or program a clearly defined virtual address space. This space holds the program and all related data. Should the process require more space, it is requested from the operating system and allocated if available. In this way, the operating system can keep two processes from accidentally or intentionally accessing each other’s memory.
Another purpose of process isolation is to enable programs to run while ensuring that they do not affect vital systems. It can prevent a program from attempting to access key areas of the operating system and modify or otherwise change them. This allows a program to be terminated in the event of a problem without causing the larger operating system also to shut down.
There are different variations of isolation. One is to assign privileges to process so they are able to access specific resources on a system while still protecting others. This is often done to allow a program to use an Internet socket or printer while still restricting it from accessing a disk drive or file system.
There also are situations in which certain steps can be taken to allow different processes to safely communicate with one another but continue to keep them independent of one another. Through mechanisms such as inter-process communication (IPC) and shared memory, processes can exchange information but still be restricted to their own memory space. This functionality is important when a process requires information from different management processes owned by the operating system.
Process isolation is an important software and hardware feature that helps to make several technologies possible. Virtual machine servers operate with an advanced form of process isolation based in both hardware and software management. Safely being able to run applets or other scripts from websites relies on a process being isolated from important system resources. Mobile devices and embedded systems use process isolation to allow core hardware to remain secure despite any faulty or malicious software being run.