Operating Systems & Networking: Operating Systems

Multi-User Operating Systems

*Allow multiple users to simultaneously use the programs on a single computer *Should only allow users who have the necessary knowledge to use the system *Are complex systems requiring a lot of upkeep and maintenance *Include Unix and Linux operating systems

Graphical User Interface (GUI)

*Allows uses to operate computers without knowing the language used to communicate with an operating system *Makes computers much more efficient *Eases the complications of operating a computer

Computers

*Are machines able to store, retrieve and process information *Can be classified by size and power

Operating Systems

*Are programs acting as translators between a computer user and the computer itself *control and manage all other programs a computer contains *Are the master program making everything else run *can be considered the core software and the computer user

Single-User, Multi-Tasking Operating Systems

*Are the most common type of system found on PCs *Allow the user to run several computer applications at the same time *Include Windows (Microsoft) and Macintosh (Apple) platforms

Real-Time Operating Systems

*Do not allow the user to have much control over the system *Are used for real-time applications such as: thermostats, mobile phones, spacecrafts, etc.

Unix

*Is a multi-user, multitasking operating system *Designed to be a small, flexible system for use by computer programmers *Not very user-friendly for the average, everyday user *GUIs have recently been created to help make it easier to use for average users

Limix

*Is a variation of the Unix operating system *Originally created by a student at the University of Helsinki named Linus Torvalds *Is a multi-user, multi-tasking operating system *Allows source code to be free to the public so it can be re-created by other with necessary modifications

Macintosh

*Is an operating system created by Apple *Is a single-user, multi-tasking operating system *Also uses GUI to help ease the difficulty level for users *Allows users to run old Macintosh applications through the system

Windows

*Was created by the Microsoft Corporation for use on PCs *Is a single-user, multi-tasking operating system *Previously needed to be downloaded after a computer was purchased *Pre-installed on almost all new personal computers *Is estimated to run on around 90 percent of all PCs *Utilizes a graphical user interface so users do not have to learn difficult demands

File Management requires the operating system to:

-create and delete files -create and delete directories -support primitives for manipulating files and directories -map files onto secondary storage -backup files on stable storage media

Security Management requires the operating system to:

-distinguish between authorized and unauthorized users -only allow authorized users to access the files and resources -provide a means of enforcement -specify the controls to be imposed

Memory management requires the operating system to:

-keep track of which parts of memory are currently being used and who is using them - determine which processes to load when memory space becomes available -allocate and de-allocate memory space when necessary

Real-Time Operating Systems are used to control the following:

-machinery -scientific tools -industrial instruments

Computers break down into the five main following types:

-minicomputer -mainframe -supercomputer

Hardware Management requires the operating system to:

-monitor the status of each device -enforce policies to determine which process will get device time and how long for -allocate and de-allocate hardware

Computers break down into the five main following types:

-personal computer -work station

Graphical User Interface utilizes the following tools:

-pointer -pointing device -icons -desktop -windows -menus

Process Management requires the operating system to complete the following tasks:

-process creation and deletion -process suspension and resumption -process synchronization and communication

Operating Systems performs basics tasks to make sure the computer works correctly, most importantly include:

-process management -memory management -file management -hardware management -security management

Operating Systems include the following four general types:

-real-time operating systems -single-user, single task operating systems -single-user multi-tasking operating systems -multi-user operating systems

Computers include the following characteristics:

-respond to specific instructions in a precise manner -can perform a prerecorded set of instructions -able to store and retrieve large amounts of information -use operating systems to function effectively

Single-User, single Task Operating Systems

Allow users to do only one thing at any given time

Personal computer

Small, single-user computer; used in hoes and businesses; based on a microprocessor

Application:

a computer program performing a specific task

minicomputer

a multi-user computer designed to handle hundreds of users at the same time

Computer Programmer:

a person who designs, writes and installs computer programs and applications

mainframe

a powerful, multi-user computer; can support hundreds or thousands of users simultaneously

Pointer:

a symbol (usually an arrow) on a computer screen used to select objects

menus:

allow users to select commands from a list of choices

desktop:

an area on a display screen where icons are displayed

supercomputer

an extremely fast computer; can perform hundreds of millions of instructions every second

Pointing devices:

an object such as a mouse used for pointing

windows:

divide the screen into different areas so several programs can run at the same time

work station

powerful, single-user computer; more powerful microprocessor than PCs

Software

programs directing the operation of computers; instructions for a computer

icons:

small pictures on a computer screen representing programs and applications

Single-User, single Task Operating Systems include Personal Digital Assistants or PDAs

small, handheld computers only allow users to operate one application at a time

Microprocessor

the master control circuit of a computer

Hardware

the physical and mechanical components of a computer such as: monitor, mouse, chips, keyboard, etc.

Source Code:

the tags and instructions developed by the creator explaining how the system was created