Chapter 4 Flashcards
What is an operating system?
A type of system software that acts as the master controller for all activities that take place within a computer system
What does an operating system do?
Provides an environment for running software and controlling peripheral devices
Resource
Any component that is required to perform work
Ex. The processor is a computer’s main resource
How do operating systems manage processor resources?
Operating system must ensure that each process receives its share of microprocessor cycles
How do operating systems handle so many processes?
Multitasking, multithreading, and multiprocessing
Multitasking
Provides process and memory management services that allow two or more tasks, jobs, or programs to run simultaneously
Multithreading
Allows multiple parts, or threads, to run simultaneously within a single program
Multiprocessing
Supports a division of labor among all the processing units
How does an operating system manage memory?
Works with and executes instructions stored in RAM
Memory leak
When an application requests memory but never releases it
How does the OS keep track of storage resources?
Acts as a filing clerk that stores and retrieves files from computer’s hard drive and storage devices. Also remembers names, locations, and keeps track of empty spaces
Why does the operating system get involved with peripheral devices?
Communicates with device driver software so that data can travel smoothly between the computer and peripheral resources
Buffers
Collect and hold data while the computer is busy with other tasks
Single-user operating system
Deals with one set of input devices–those that can be controlled by one user at a time
Multiuser operating system
Allows a single, centralized computer to deal with simultaneous input, output, and processing requests from many users
Server operating system
Provides tools for managing distributed networks, e-mail servers, and Web hosting sites
Desktop operating system
Designed for a desktop or laptop personal computer
Mobile operating system
Designed for devices such as smartphones and tablet computers
Where is the operating system stored?
Usually stored on a hard disk because it is so large, but the operating system kernel is loading into RAM during the boot process
Kernel
Provides essential operating system services, such as memory management and file access
What is the boot process?
The sequence of events that occurs between the time that you turn on a computer and the time that is is ready for you to issue commands
Bootstrap program
Built into special ROM circuitry housed in the computer’s system unit
Name the six major events that happen during the boot process
- Power up
- Start boot program
- Power-on self test
- Identify peripheral devices
- Load operating system
- Check configuration and customization
Why doesn’t a computer leave operating system in memory
RAM is volatile, ROM is not large enough
How do I know when the operating system is loaded?
When the computer is ready to accept your commands
Do I ever interact directly with the OS?
When you launch programs, manage files, configure your computer equiptment
What is a user interface?
The combination of hardware and software that helps people and computer’s communicate with each other.
How does the operating system affect the user interface?
Defines the look and feel of compatible software
Command-line interface
Requires users to type memorized commands to run programs and accomplish tasks
What kind of UIs do modern computers have?
Graphical user interface: provides a way to select menu options and manipulate graphical objects displayed on the screen using a mouse or gesture
What are the basic control elements of a GUI?
- Desktops and windows
- Start screens
- Icons
- Buttons, toolbars, and taskbars
- Menus and ribbons
How similar are the user interfaces for Windows, Mac OS, and Linux?
More similar than they are different. Fairly standard set of on-screen controls, but may differ in visual design
Desktop
Visual work area that covers the entire screen and remains in the background throughout a computing session
Taskbar or dock
Included in the desktop for launching applications, which are displayed in rectangular application windows
Start screen
Appears at the end of a boot process and whenever it is evoked by the user, commonly by pressing the Home button
Icon and tiles
An icon is a small picture that represents a program, file, or hardware device. Some icons are designed as tiles.
Buttons and toolbar
A button is a graphic that can be clicked to make a selection; Can be arranged in a toolbar
Menu and menu bar
A menu displays a list of commands or options on a menu bar
Ribbon
An alternative type of menu that is arranged as rows of tools on a succession of tabs
Submenu
An additional set of commands that the computer displays after you make a selection from the main menu
Dialog box
Displays the options associated with a command
What’s the best-selling operating system?
Microsoft Windows
Disk Operating System (DOS)
The command-line operating system used in the first PCs
Why “Windows”?
Got its name from the rectangular work areas on the screen-based desktop
Does Windows 8 run on tablets and phones too?
Windows RT is designed for tablet devices
Windows Phone 8 is designed for smartphones
What are the strengths of Windows?
- Best selection of software
- Windows user community
- Vast array of peripheral devices
What the the weaknesses of Windows?
- Reliability
- Security
What is unique about Mac OS?
Mac OS is the operating system designed for Apple’s Macintosh line of computer systems. Unique features include the Apple icon, Dock, and application menu bar fixed at the top
What are the strengths of Mac OS?
- Easy to use
- Reliable
- Secure
What is dual boot?
Utility that can switch between Mac OS X and Windows
What is a virtual machine?
Allow you to use one computer to simulate the hardware and software of another
What are the weaknesses of Mac OS?
- Limited selection of software
- Resource forks
What is a resource fork?
Data fork is similar to files in other operating systems, but the resource fork is a companion file that stores information about the data in the data fork
What is iOS?
Operating system for the Apple iPhone
Is iOS related to Mac OS X?
Yes, derived from the Mac OS X code
What are the limitations of iOS?
- Limits apps to Apple App store
- Does not include file manager
- Limited multitasking
What is Android?
Popular platform for tablet computer, smartphones, and ebook readers
What’s unique about Android?
- Voice input for Google searching, voice dialing, navigation, etc.
- Can become a WiFi hotspot
- Access to file system
UNIX
Developed in 1969 at AT&T’s Bell Labs; good reputation for dependability in multiuser environments
Linux
Developed in 1991; inspired by and loosely based on a UNIX derivative called MINIX; often used as an operating system for servers
Strengths of Linux
- Distributed with source code under the terms of a GPL (General Public License)
- Multitasking and multiuser capabilities
- Secure and reliable
What are the weaknesses of Linux?
- More tinkering
- Limited number of programs
Linux distribution
A download that contains the Linux kernel, system utilities, graphical user interface, and an installation routine
What is BlackBerry OS?
Proprietary operating system produced by RIM, the company that developed the BlackBerry smartphone; key feature is its ability to work with corporate e-mail software systems
What’s unique about BlackBerry OS?
- Pioneered push technology
- Offers direct Internet connections
- Can be integrated into a wireless platform
What is a computer file?
A named collection of data that exists on a storage medium, such as a heard disc, CD, DVD, or USB
What are the rules for naming files?
(File naming conventions)
Characters not allowed for PC: * \ : < > | “ / ?
Characters not allowed for Mac: :
Is there a maximum length for file names?
255 characters
What is a file extension?
An optional file identifier that is separated from the main file name by a period (Paint.exe)
Why are certain characters not allowed in a file name?
It may have special significance to the operating system
What are reserved words?
Used as commands or special identifiers, so these words cannot be used in a file name
How do I designate a file’s location?
Specify where the file is stored
What does C: mean?
The main hard disc is referred to as C. A device letter is usually followed by a colon, so C: is typically the designation for a hard disc drive
What is a disc partition?
A section of a hard drive that is treated as a separate storage unit
Directory
Contains a list of a a storage device’s files
Root directory
The main directory of a storage device
Subdirectory
A subdivision of a root directory
Folder
The way in which a subdirectory is depicted
File specification
(Path) Includes the drive letter, folder, file name, and extension
What is a file format?
Organization and layout of data that is stored in a file
File header
A section of data at the beginning of a file that contains information about a file, such as the date it was created, the data it was last updated, its size, and its file type
Is a file extension the same as a file format?
No. The file extension is a good indicator of a file’s format, but it does not define the format.
Native file format
A software application can open files that exist in its native file format, plus several additional file formats
Why can’t I open some files?
- The file is damaged
- Someone changed the file extension
- Your software might not have the capability to open a particular version of the format
How does a software application help me manage files?
- Provides a way to open files and save them
- Allow you to delete and rename files
What should I know about saving files?
- Save option
- File tag
File tag
Describes the file’s contents
Save vs. Save As
Save As: allows you to select a name and storage device for a file
Save: Saves under its current name and location
Metadata
“data about data”; describes the contents of a file
File management utility
Helps you work with groups of files or perform other file operations (Ex. Windows File Explorer/ Mac OS X Finder)
Logical storage models
Help you form a mental (logical) picture of the way in which your files are stored
What are typical filing metaphors?
Filing cabinet, tree
File Explorer
A utility program bundled with the Windows operating system and designed to help you organize and manipulate the files stored on your computer
What can I do with the folders and files listed in the file explorer?
Rename, copy, move, delete
Library
Similar to a folder in that it can be used to group similar files, but it cannot store files, but it contains a set of links to files that are stored on various devices and folders
Physical storage model
Describes what actually happens on the discs and in the circuits, contrary to the logical storage model
Formatting
Prepares the surface of a disc to hold data in storage; divides into tracks (all around) and sectors (part of a track)
Disc mastering
The process of creating a CD, DVD, or BD by selecting all the files and then copying them in a single session
Packet writing
Recording technology that lets you record in multiple sessions
File system
Used by the operating system to keep track of the names and locations of files that reside on a storage medium
Cluster
A disc drive usually works with a cluster (or block) to speed up the process of storing and retrieving data
File shredder software
Deletes data from a disk in such a way that no one can ever read it
Fragmented files
Files scattered all over the disc and stored in noncontiguous clusters
Defragmentation utility
Rearranges files on a disc so that they are stored in contiguous clusters
Backup
Stores the files needed to recover data that’s been wiped out by operator error, viruses, or hardware failures
Online backup services
Web sites that offer storage space for backups
Synchronization
Compares the content of files on two devices and makes them the same
Full system backup
Includes a copy of every file stored on your computer’s hard drive as well as installed programs, settings, and the operating system
Boot disc
Removable storage medium containing the operating system files needed to boot your computer without accessing the hard disc
Recovery disc
A bootable CD, DVD, or other media that contains a complete copy of your computer’s hard disk as it was when the computer was new
Recovery partition
Convenient for restoring a corrupted device driver or software module because you can simply copy or reinstall the file from the recovery partition to the main partition
Windows Registry
An important group of files used by the Windows operating system to store configuration information about all the devices and software installed on a computer system
Restore point
Snapshot of your computer settings; Backups of the Windows Registry
Backup software
A set of utility programs designed to back up and restore some or all of the files on a computer’s primary storage device
Differential backup
Makes a backup of only those files that were added or changed since your last full backup session
Incremental backup
Backs up files that were added or changed since the last backup, full or incremental
Bare-metal restore
Restore a computer’s operating system, device drivers, settings, and data in a single step
Disk image
Bit-by-bit copy of the data from all sectors of a disk
