Chapter 4 - System Software

Linux OS

-"open source software", source code is available to users -powerful, free runs same software as Windows -gaining acceptance for web servers -disadvantages include: lack of technical support and less software available because it cannot run Microsoft office or Mac software

What are the (3) types of user interfaces

-Graphic user interface (GUI -Menu-driven Interface -Command-line user interface

What are the (3) categories of OSs

-Stand-alone operating systems: used by single users -Server operating systems: used in client/server network environments -Embedded operating systems: found on ROM chips in portable or dedicated devices

Embedded OS'

-designed for specific applications -compact and efficient -eliminate many unneeded features of OS' -used in PDAs, cell phones, kitchen appliances, point-of-sales deices...etc

Android (Embedded OS)

-free -made by google -different devices do not always work the same (inconsistent)

Microsoft Windows OS (all versions)

-many different version from Windows 98 to Windows 8 -most used OS in the world (90%) -more software for Windows -not considered to be as stable as other OS'

Iphone OS

-not free -made by Apple -consistent

Unix OS

-oldest OS (late 60s) -preemptive multitasking -has many versions that are not compatible -for larger computers -Hard to use and defaults to a command-line user interface -Mac OS x and Linux is based on Unix -most powerful OS

Menu-driven interface

-provides text-based menus -displays available user options

Command-line user interface

-requires the user to type commands to instruct the OS to perform the desired actions -uses complicated rules of syntax

Mac OS

-used on macintosh personal computers -first commercial OS to use a GUI (graphic use interface) -second on the market -more expensive -most stable, simplest to use -also can run Windows programs -latest version is Mac OS x Snow Leopard

What are the 5 basic functions of the Operating System

1. Start the computer 2. Manages applications 3. Manages memory 4. Handles input/output device messages 5. Provides a user interface for communication

What two categories make up the Sytem Software

1. The Operating System 2. System Utilities (utility programs)

What is an Operating System (OS)

A set of programs that coordinates: 1. Interactions of hardware components to each other 2. Interaction between application software and computer hardware

When coordination tasks, what are "interrupt handlers"

AKA interrupt service routines; miniprograms that immediately respond when an interrupt occurs

What is System Software

All the programs that enable the computer and its peripheral devices to function smoothly.

What is the "buffer" (managing memory)

Area that holds data and instructions temporarily and makes programs run faster; RAM functions as the "buffer" - the OS gives each program a portion of the RAM memory and keeps them from interfering with each other.

What is hapening when you boot the computer

Loading the Operating System (OS) into the RAM

What is a "warm boot"

Restarting a computer that is already on

What is a "cold boot"

Starting the computer when it has not yet been turned on

What is the "foreground" application

When multi-tasking, it is the active application (in current use)

What is the "background" application

When multi-tasking, it is the application that appears inactive (not in current use)

What is the most recent Microsoft OS

Windows 7

% of OS usage

Windows ~92% Mac ~5% Linux ~2%

When coordinating tasks, what is an "interrupt request" (IRQ)

actual interrupting of an event by an interrupt signal

What is the best way to improve your computer (managing memory)

adding more RAM because paging slows the computer and accessing data from the hard disk is slower than accessing data from RAM

What is a "multi-tasking" operating system

allows more than one application to run at the same time

Backup software

copies data found on the hard disk to a backup device

"Drive Image Software"

creates a mirror image of the entire hard drive

What is a "device driver"

enables communication between computer and devices

"Search Utility" (Searching for and Managing files)

enables you to locate files

What is "preemptive" multi-tasking

ensures that all applications have fair access to the CPU

When coordinating tasks, what is an "interrupt vector table"

holds responses from multiple interrupts inRAM, where the OS processes them in the highest to lowest priority order

"Full Backup"

include all files and data in the backup

"Incremental Backup"

include only the files changed or added since the previous backup

What is the purpose of "providing the user interface"

it allows users to: -start application programs -manage storage devices -safely shut down computer

Server OS'

more powerful to easily handle having other computers asking for information. E.g., linux and Unix OS

Antivirus software

protects the computer from viruses; a popular antivirus program is "Avast!" -programs need to be continually updated to protect against new forms of viruses

What is a "single-tasking" operating system

runs only one application at a time

When coordinating tasks, what are "interrupts"

signals created by input and output devices that notify the OS when actions are taken

System Utilities (utility programs)

software programs are essential to effective management of the computer system -performs tasks such as: backing files, providing antivirus protection, searching for and managing files, compressing files, providing accessibility utilities

What is "virtual memory" (managing memory)

uses a portion of the hard disk to extend RAM. - Includes "pages" which are units of fixed size, contain program instructions and data. - whenRAM is full, copies of pages are temporarily stored in a "swap file" which is a special hard disk file. - "paging" is when files between RAM and the hard disk are transferred -"thrashing" is when there is excessive paging

Graphic user interface (GUI)

uses icons- small images that represent computer resources used to initiate actions and appear on desktop

"File Manager" (Searching for and Managing files)

utility software that organizes and manages data (copy files, determine how and where files are stored, delete files