Significant Technical Features of The OS Itself
ITS introduced many revolutionary features:
- It had the first device-independent graphics terminal output; programs generated generic commands to control screen content, which the system automatically translated into the appropriate character sequences for the particular type of terminal operated by the user.
- A general mechanism for implementing virtual devices in software which ran in user processes (which were called "jobs" in ITS).
- Using this mechanism, it provided transparent inter-machine filesystem access (almost certainly the first operating system to do so). The ITS machines were all connected to the ARPAnet, and a user on one could perform the same operations on files on other ITS machines as on local files.
- Sophisticated process management; user processes were organized in a tree, and a superior process could control a large number of inferior processes. Any inferior process could be frozen at any point in its operation, and its state (including contents of the registers) examined; the process could then be restarted transparently.
- An advanced software interrupt facility that allowed user processes to operate asynchronously, using complex interrupt handling mechanisms.
- PCLSRing, a mechanism which provided what appeared (to user processes) to be quasi-atomic, safely interruptible system calls. No process could ever observe any process (including itself) in the middle of executing any system call.
- In support of the AI Lab's robotics work, ITS also supported simultaneous real-time and time-sharing operation.
Many of these, and numerous other significant advances, were later picked up by other operating systems.
Read more about this topic: Incompatible Timesharing System
Famous quotes containing the words significant, technical and/or features:
“Every American, to the last man, lays claim to a “sense” of humor and guards it as his most significant spiritual trait, yet rejects humor as a contaminating element wherever found. America is a nation of comics and comedians; nevertheless, humor has no stature and is accepted only after the death of the perpetrator.”
—E.B. (Elwyn Brooks)
“Where there is the necessary technical skill to move mountains, there is no need for the faith that moves mountains.”
—Eric Hoffer (1902–1983)
“It is a tribute to the peculiar horror of contemporary life that it makes the worst features of earlier times—the stupefaction of the masses, the obsessed and driven lives of the bourgeoisie—seem attractive by comparison.”
—Christopher Lasch (b. 1932)