Operating Systems Introduction
What we have • A layer of software called the operating system • Windows, Linux, FreeBSD, or Max OS X • GUI (Graphical User Interface)
WHAT IS AN OPERATING SYSTEM? • Huge, complex, and long-lived • Linux or Windows is on the order of five million lines of code • The Operating System as an Extended Machine
Operating System as a Resource Manager • Operating systems allow multiple programs to run at the same time • Resource management includes multiplexing (sharing) resources • Allocating disk space and keeping track of who is using which disk blocks is a typical operating system resourcemanagement task.
HISTORY OF OPERATING SYSTEMS • First Generation (1945-55) Vacuum Tubes • Second Generation (1955-65) Transistors and Batch Systems
Third Generation (1965-1980) ICs and Multiprogramming • The IBM 360 was the first major computer line to use (small-scale) Ics (Integrated Circuits) • CTSS (Compatible Time Sharing System), was developed at M.I.T.
The Fourth Generation (1980-Present) Personal Computers • In 1974, when Intel came out with the 8080 • CP/M (Control) Program for Microcomputers) • IBM designed the IBM PC • IBM PC/AT, came out in 1983 with the Intel 80286 CPU, MS-DOS
Mainframe Operating Systems • Server Operating Systems • Multiprocessor Operating Systems • Personal Computer Operating Systems • Handheld Computer Operating Systems • Embedded Operating Systems • Sensor Node Operating Systems • Real-Time Operating Systems • Smart Card Operating Systems
OPERATING SYSTEM CONCEPTS • Processes • Protection • The Shell • Large Memories • Disks • Virtual Memory