Download presentation
Presentation is loading. Please wait.
1
© 2004, D. J. Foreman 1 CS350 Operating Systems
2
© 2004, D. J. Foreman 2 Administrivia Assignments ■ Homework on most chapters ■ Approximately 8 lab assignments Exams ■ Midterm ■ Final (comprehensive) Quizzes ■ Random, 10 minutes each Grades required to pass (after curving) ■ >= 70 average on labs ■ >= 70 average on (h/w + quizzes) together ■ >= 60 on midterm to pass
3
© 2004, D. J. Foreman 3 Course Outline
4
© 2004, D. J. Foreman 4 Introduction & Motivation Wanted – a methodology to: ■ get more work done in a fixed time ■ allow multiple users on 1 computer ■ allow programs to interact with each other ■ maximize memory and CPU utilization ■ reduce the need for device handling ■ allow programs' parts to be shared ■ make the system more usable (friendlier?) ■ make system faster
5
© 2004, D. J. Foreman 5 Why Study Operating Systems? Understand support structure so we can: –Exploit system features –Learn to write more effective code Learn to design an OS
6
© 2004, D. J. Foreman 6 What IS an Operating System? A "virtual machine" that provides: ■ An abstraction of some virtual computer ■ Common functionality for apps ■ Security across apps/devices ■ Some level of concurrency (maybe) ■ Portability across real machines ■ Simplified access to resources ■ Sharing of resources ■ Services for apps
7
© 2004, D. J. Foreman 7 Perspectives End user ■ Getting work done Application programmer ■ More efficient use of system ■ Make work easier for user O/S programmer ■ Exploit h/w ■ Enhance performance, usability
8
© 2004, D. J. Foreman 8 Examples of System Software Tools- a DBMS API's- functions to create windows Resident programs – resource mgmt
9
© 2004, D. J. Foreman 9 Abstractions User ■ Windows, folders Application programmer ■ OS, language API's ■ Run-time libraries & DLL's ■ Shell OS programmer ■ Hardware interfaces ■ Machine instructions ■ OS service interfaces
10
© 2004, D. J. Foreman 10 Abstract View of System User Space O/S Space Application Programming Interface
11
© 2004, D. J. Foreman 11 The API Application Programming Interface ■ Exposes a portion of an environment ■ Provides services I/O Memory Protection Security
12
© 2004, D. J. Foreman 12 Evolution of OS's Uni-programming ■ DOS Apparent multiprogramming ■ Windows Versions 2 to 3.1 True multi-programming ■ UNIX/LINUX, OS/2, Windows95+ ■ Mainframe systems: MVS, VMS, VM Multithreading (mainstream systems) ■ OS/2 ■ System-V (AIX, Solaris, SCO Unixware) ■ Windows 95/98/NT/XP, 200x ■ Linux
13
© 2004, D. J. Foreman 13 OS Strategies Batch ■ All work pre-scheduled Timesharing ■ Multi-user, Interactive PC's and Workstations ■ Single-user, interactive Embedded ■ Satellites, robots, etc PDA's ■ Single-user, interactive, small Network OS's ■ Multi-machine, multi-user
14
© 2004, D. J. Foreman 14 Resource Management Resources ■ Memory ■ CPU cycles ■ I/O Includes networks, robot arms, motors That is, any means of getting information (or signals) into or out of the computer
15
© 2004, D. J. Foreman 15 Resource Sharing Why do we need to share? ■ Greater throughput ■ Lowers cost of resources ■ Allows more resources to be available
16
© 2004, D. J. Foreman 16 The Kernel Implements O/S functions Privileged, non-interruptible Sometimes reduced to a "micro-kernel" ■ Absolutely minimal set of functions required to be in privileged mode ■ Micro-kernel does NOT include : Device drivers File services Process server Virtual memory mgmt
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.