rendor
Uploaded by
25 SLIDES
393 VUES
250LIKES

Overview of Operating Systems: Functions, Types, and Process Management

DESCRIPTION

This review covers key concepts in operating systems, including process management and memory allocation. Each process runs in its own address space, divided into instruction, data, and stack regions, while memory management techniques like fixed and variable partitioning are discussed. The operating system serves as a gatekeeper, managing hardware resources and facilitating interaction between users and applications. Scheduling algorithms like FIFO and Round-Robin are explained, along with the importance of efficiency and error detection. Finally, the relationship between operating systems and security is questioned.

1 / 25

Télécharger la présentation

Overview of Operating Systems: Functions, Types, and Process Management

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. Week 4 Operating Systems

  2. Review • Program set of instructions • Process / task program in execution • Each process has it’s own address space • Consisting of instruction region • Data region • Stack region • Process run for an interval or quantum of time

  3. Single-user, dedicated machine Memory OS User program Unused

  4. Uni-programming • Difficult application development • Assembler or machine language • No error recovery • Job scheduling (batch processing) • Processor had to do all operations • Inefficient use of resources • Non real-time

  5. Operating System • Definition “software that controls hardware” • Resource manager - Gatekeeper • Interface between user and hardware • Separates application from hardware • File manager • Kernel is the core component of the OS

  6. OS Objectives and Functions • Convenience • Making the computer easier to use • Efficiency • Allowing better use of computer resources • Simplicity • Application developers can use system procedures to reduce code

  7. Multiprogramming • Carve memory into partitions • Unique app’s loaded into each partition • Operating system switches HW resources between partitions for a quantum of time • Appears to run simultaneously • Efficient use of processor resources • Real-time data • Con = overhead, complex

  8. Hardware M E M O R Y Operating System M E M O R Y Time a Time b Time c Partition 1 Partition 2 Partition 3 Application a Application b Application c

  9. Process states • Running • Ready • Blocked • Wait • Suspended

  10. Scheduling Algorithms • First-In-First-Out FIFO • Round-Robin RR • Shortest-Process-First SPF • Shortest-Remaining-Time SRT • Multilevel Feedback Queue • Fair Share Scheduling

  11. FIFO

  12. RR Job Queue Completion CPU A C B A Preemption

  13. Process control block • PID- Process identification number • PC- Program counter • Registers • State • Priority • Address space • Flags / etc

  14. Layers and Views of a Computer System

  15. Operating System Services • Program creation • Program execution • Access to I/O devices • Controlled access to files • System access • Error detection and response • Accounting

  16. O/S as a Resource Manager

  17. Memory management • Fixed size partitioning • Variable-size partitioning • Fragmentation • Memory leak

  18. Virtual memory Disk Memory 4K Page Segment 4K Page Segment 4K Page Segment 4K Page Segment Free

  19. LPAR

  20. $64 Million Question $$$$$$$$$$$$$$$$$$$$$$$ What does this have to do with security? $$$$$$$$$$$$$$$$$$$$$$$

More Related