1 / 6

Necessary Background for OS

Necessary Background for OS. Dr. John Abraham Professor UTRGV. Software. Application software For specific task that a user runs System software Operating System and other programs that are not application software. Allows application programs to run

hanh
Download Presentation

Necessary Background for OS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Necessary Background for OS Dr. John Abraham Professor UTRGV Dr. John Abraham, Professor UTRGV

  2. Software • Application software • For specific task that a user runs • System software • Operating System and other programs that are not application software. • Allows application programs to run • Allows application programs to use I/O devices through syscalls Dr. John Abraham, Professor UTRGV

  3. Operating system • Sits between user and the hardware so that user need not know the details of the hardware • Users can’t access computer resources directly, OS handles it for the user • Explain experiences with pokes and peeks • If a user is allowed to use resources directly such as a printer, the user can tie up the resource from others. • Explain my experiences with plotters Dr. John Abraham, Professor UTRGV

  4. Functions of Operating System • Resource management: • CPU (processor management) using PCB, Scheduler, Dispatcher • Memory management (cache, RAM) • I/O devices management • Storage management, Directories, subdirectories, file Allocation Tables, etc. • Security – who can access what • Controls (governs) execution of all programs • Goals of OS • Ease of use (convenience), GUI, command line interface (CLI) of character line interface • Efficiency Dr. John Abraham, Professor UTRGV

  5. Types of Operating Systems • System Operator (SysOps) • Batch processing. Explain my experiences • Job – program, input data plus control instructions • User does not interact with the operating system • Multiprogramming, many processes • One processor at a time is allocated to CPU. The program may exit when waiting for IO, and another process can use the CPU. Large programs may monopolize the CPU, when small programs simply wait • Multi-tasking • Time slice or priority will switch processes in/out of cpu (round robin, etc), interrupts (Hardware, software) based context switching (PCB) • Multi-processing. Many processors. One process to each processor, or portions of each process handled by several cpu’s • Real-time. Time dependent for mission critical. Immediate response needed. Military, gas refinery, etc. Dr. John Abraham, Professor UTRGV

  6. Generations of operating system • 1940s Users had complete access to machine language, so no OS. • 1950s Jobs oriented OS. Significant time was lost between jobs. Batch oriented. Sysop decided what is stored on which tape. • 1960s supported Multiprogramming. Several processes brought into RAM. A job monopolized the CPU until I/O is needed. Then swapped out. OS decided what is stored on which tape, issued instruction to sysop to load the tape. Timesharing systems appeared here. • 1970s IBM 360 – multimode system that supported all the above. • Late 1970s (unbundled hardware from software) and networking and distributed data processing. Dr. John Abraham, Professor UTRGV

More Related