Operating Systems Sara Mullan Johns Hopkins University Fall

Who is the manager of your computer? The Operating System Answer

What is an operating system?

What is an operating system? A software program which runs on a computer –Consists of programs and data Enables the computer hardware to communicate and operate with the computer software –Manager of resources Most important program which runs on a computer

When is an operating system loaded onto a computer ? First thing Answer

How does an operating system help a computer? Basic Tasks: –Recognizing input –Sending output –Controlling peripheral devices (printers, disk drives) Keep up with needs Interact with users

How does an operating system work? Allocation and assignment of system resources: –Input and output devices –Software –Central processing unit Scheduling: –Follows priority –Coordinates resources and jobs Monitoring: –Monitors and tracks activities in the computer system

What are an operating system’s tasks? Memory management Processor management Storage management Device management Application interface User interface

What are an operating system’s parts? Kernel –Controls low-level processes How information is sent and received How to interpret information received How memory is read and written User Interface –Interacts with the computer user directly User can control and use programs May be graphical Application Programming Interfaces –Provide services and code libraries

Features Multi-user –Two or more users can run the programs simultaneously Multiprocessing –Enables a program to run on more than one CPU Multitasking –Allows programs to run at the same time Multithreading –Allows multiples parts of a program to run at the same time Graphical User Interface –Contains graphics and icons Real Time –Responds to input right away

History of Operating Systems Early computers were similar to a calculator. –Built to perform a series of single tasks –Could only execute one program at a time Operating Systems have continually evolved since the 1940s –Consumer needs –Changes in computer capabilities

Examples of Commonly Used Operating Systems Windows Mac OS Linux Unix There are many other examples of operating systems.

Timeline 1971 –MULTICS was released by UNIX experimental operating system 1978 –development of Apple DOS 3.1 –first Apple operating system 1985 –Microsoft introduced Windows –overtook Mac OS 1991 –Linux began to create a new operating system kernel

Windows Developed by Microsoft Most popular PC operating system Windows 7 is the latest version released Security criticized by customers Default programs included Typical for the general consumer and a software developer

Mac Developed by Apple Second most popular PC operating system Snow Leopard is the latest version released Default programs included Typical for picture and video editing the-Apple-Security-Software-Recommendations/

Linux Developed by Linux Torvalds Alternative to Windows Gaining in popularity

UNIX Originally developed in 1969 by a group of AT&T employees at Bell Labs Widely used in servers, workstations, and mobile devices

Comparing Apple and Microsoft NameCreatorFirst Public Release Latest Stable Version CostTarget System Type Mac OSApple Inc Yes WorkstationWorkstation, Personal computerPersonal computer Mac OS XApple Inc Yes WorkstationWorkstation, Personal computer, Embedded systemPersonal computerEmbedded system Mac OS X Server Apple Inc YesServer Windows ServerWindows Server (NT family) Microsoft Yes ServerServer, NetApp, Embedded system, HPCNetAppEmbedded systemHPC Microsoft WindowsMicrosoft Windows (NT family) Microsoft Yes WorkstationWorkstation, Personal computer, Media center, Tablet PC, Embedded systemPersonal computerMedia center Tablet PCEmbedded system Microsoft Windows Microsoft Windows (Classic family) Microsoft Yes Personal computerPersonal computer, Media centerMedia center

Statistics on Usage 90% of the market share for operating systems for the personal computer is Microsoft. Answer

Usage Share of Web Client Operating Systems

Market Share

Pros Keep up with the needs which change over time Direct hardware access No coding necessary Security Made out of portable code. –This allows them to be changed or modified. Add an application, add a new security update

Cons Manufacturing costs increase Upgrades often needed Takes up memory and processing resources Additional security often necessary

Educational Connection Can use hardware and software resources Controls your input and output Share resources within among a group of users Makes your job easier Makes sure different users and programs don’t interfere with each other when running at the same time Security –Makes sure unauthorized users don’t assess the system

Work Cited See attached Word document.