Appendix A: Hardware and Software Basics

hardware

Consists of the physical devices associated with a computer system.

software

The set of instructions the hardware executes to carry out specific tasks.

computer

An electronic device operating under the control of instructions stored in its own memory that can accept, manipulate, and store data.

Hardware and software overview

Hardware components of a computer system

How the hardware components work together

central processing unit (CPU) (or microprocessor)

The actual hardware that interprets and executes the program (software) instructions and coordinates how all the other hardware devices work together.

central processing unit (CPU) (or microprocessor)

The actual hardware that interprets and executes the program (software) instructions and coordinates how all the other hardware devices work together.

control unit

Interprets software instructions and literally tells the other hardware devices what to do, based on the software instructions.

arithmetic-logic unit (ALU)

Performs all arithmetic operations (for example, addition and subtraction) and all logic operations (such as sorting and comparing numbers).

megahertz (MHz)

The number of millions of CPU cycles per second.

gigahertz (GHz)

The number of billions of CPU cycles per second.

complex instruction set computer (CISC) chip

Type of CPU that can recognize as many as 100 or more instructions, enough to carry out most computations directly.

reduced instruction set computer (RISC) chip

Limits the number of instructions the CPU can execute to increase processing speed.

primary storage

Computer’s main memory, which consists of the random access memory (RAM), cache memory, and read-only memory (ROM) that is directly accessible to the CPU.

random access memory (RAM)

The computer’s primary working memory, in which program instructions and data are stored so that they can be accessed directly by the CPU via the processor’s high-speed external data bus.

volatility

Refers to a device’s ability to function with or without power.

volatile

Must have constant power to function; contents are lost when the computer’s electric supply fails.

cache memory

A small unit of ultra-fast memory that is used to store recently accessed or frequently accessed data so that the CPU does not have to retrieve this data from slower memory circuits such as RAM.

read-only memory (ROM)

The portion of a computer’s primary storage that does not lose its contents when one switches off the power.

nonvolatile

Does not require constant power to function.

flash memory

A special type of rewritable read-only memory (ROM) that is compact and portable.

memory cards

Contain high-capacity storage that holds data such as captured images, music, or text files.

memory sticks

Provide nonvolatile memory for a range of portable devices including computers, digital cameras, MP3 players, and PDAs.

secondary storage

Consists of equipment designed to store large volumes of data for long-term storage.

megabyte (MB, M, or Meg)

Roughly 1 million bytes.

gigabyte (GB)

Roughly 1 billion bytes.

terabyte (TB)

Roughly 1 trillion bytes.

magnetic medium

A secondary storage medium that uses magnetic techniques to store and retrieve data on disks or tapes coated with magnetically sensitive materials.

magnetic tape

An older secondary storage medium that uses a strip of thin plastic coated with a magnetically sensitive recording medium.

hard drive

A secondary storage medium that uses several rigid disks coated with a magnetically sensitive material and housed together with the recording heads in a hermetically sealed mechanism.

solid state drive

An all-electronic storage device that is an alternative to a hard disk and is faster than a hard disk because there is zero latency (no read/write head to move).

input device

Equipment used to capture information and commands.

stylus

A penlike device used to tap the screen to enter commands.

Input devices

adaptive computer devices

Input devices designed for special applications for use by people with different types of special needs.

output device

Equipment used to see, hear, or otherwise accept the results of information processing requests.

Output devices

communication device

Equipment used to send information and receive it from one location to another.

Supercomputer

appliance

A computer dedicated to a single function, such as a calculator or computer game.

ebook

An electronic book that can be read on a computer or special reading device.

Computer categories

system software

Controls how the various technology tools work together along with the application software.

operating system software

Controls the application software and manages how the hardware devices work together.

dual boot

Provides the user with the option of choosing the operating system when the computer is turned on.

embedded operating system

Used for a single purpose in computer appliances and special-purpose applications, such as an automobile, ATM, or media player.

multitasking

Allows more than one piece of software to be used at a time.

utility software

Provides additional functionality to the operating system.

control panel

A Windows feature that provides a group of options that sets default values for the Windows operating system.

system clock

Works like a wristwatch and uses a battery mounted on the motherboard to provide power when the computer is turned off.

safe mode

Occurs if the system is failing and will load only the most essential parts of the operating system and will not run many of the background operating utilities.

system restore

Enables a user to return to the previous operating system.

application software

Used for specific information processing needs, including payroll, customer relationship management, project management, training, and many others.

personal information management (PIM) software

Software that handles contact information, appointments, task lists, and email.

course management software

Contains course information such as a syllabus and assignments and offers drop boxes for quizzes and homework, along with a grade book.

software updates (software patch)

Occurs when the software vendor releases updates to software to fix problems or enhance features.

software upgrade

Occurs when the software vendor releases a new version of the software, making significant changes to the program.

single-user license

Restricts the use of the software to one user at a time.

network user license

Enables anyone on the network to install and use the software.

site license

Enables any qualified users within the organization to install the software, regardless of whether the computer is on a network. Some employees might install the software on a home computer for working remotely.

application service provider license

Specialty software paid for on a license basis or per-use basis or usage-based licensing.