Chapter 1 Computer Basics What is a

Chapter 1 Computer Basics

What is a Computer? Functional definitions (45%) Humorous definitions (5%) Academic definitions (45%) Other (5%)

Functional Definitions “A computer is a machine that facilitates many tasks, like word processing, web searching, etc. It is a tool. ” “A computer is a machine used for many different things; multimedia, wordprocessing, & research. ” “A computer is a machine that’s purpose is to make the work of humans easier, and more time efficient. ”

Humorous Definitions “A computer is a machine that does what the operator tells it to do. ” “A computer is a thing that always crashes right when you’re in the middle of an important assignment. ” “A porn box. ”

Humorous? Definitions “A machine we, as society, have come to base our lives upon. It confuses many, and frustrates more. It can do more than man, yet men built it. They suck, though I learn to live with them. ”

Academic Definitions “A computer is something that receives and processes information and then puts out responses. ” A computer is an electronic device that stores information and/or processes that information. ” “A computer is a piece of machinery used to perform some type of calculation or task through a series of inputs and outputs. ”

Academic Definitions Classical academic definition: n “A computer is any device that receives input, processes that input, and produces output. ” In everyday life, this is too broad n n n Computers are electronic devices that primarily use binary logic and integrated circuitry They carry out a given task by executing a certain series of steps, according to programming, either in hardware or software They have a clearly distinguishable central processing unit which handles the computation

Computers For most of what we talk about in this course, we’ll assume we’re talking about desktops The primary division in a desktop computer is hardware vs. software Hardware: The physical (tangible) devices or components that make up a computer system. Software: The programs (intangible sequences of instructions) that a computer system runs. The easiest way to tell the difference between hardware and software is to kick it. If it hurts your toe, it's hardware. -- Carl Farrell

A Typical Desktop Computer

The System Unit Houses the following: n n n CPU (Central Processing Unit) RAM (main memory), hard disk drives (e. g. C: drive) floppy drives (e. g. A: drive) other drives (e. g. CD-ROM, DVD) also holds slots for various cards (e. g. network card, sound card, video card). Do not call it a “system cabinet”

Peripherals A peripheral is any part of the computer external to the system unit Peripherals allow communication between external sources (e. g. you) and your computer. Examples: n mouse, keyboard, monitor, speakers, digital camera, printer, scanner, etc.

Types of Computers Supercomputers n n n can cost millions of dollars perform trillions of operations per second may have hundreds of thousands of CPUs Mainframes n n Central computing units used by organizations (e. g. banks, airlines, insurance companies). Can support 100 s of users connected via terminals. Workstations n n Scientific, engineering, mathematical workhorses. Targeted toward a special-purpose task (e. g. numerical analysis, graphics design). Microcomputers n PCs (Personal Computers) = desktop computers, PDAs (Personal Digital Assistants), Laptops & Notebooks, Tablet PCs. Microcontrollers (Embedded Systems) n n Computers embedded in "ordinary" systems. Control your TV, telephone, microwave, CD-Player, car airbags, . .

What is Computing? Computing is a 4 -step sequence that turns raw data into useful information: n n Input Processing Storage (sometimes omitted) Output

Input is when information is received from an outside source, such as: A device: keyboard, mouse, modem, network card. Memory: DVD movie, file on hard drive, CD

Processing Done in the CPU (Central Processing Unit) The computer executes millions (or billions) of very simple instructions per second. Examples include: n n n FETCH a memory element. FETCH another memory element. ADD these memory elements together. STORE the result to memory. These instructions form the computer’s program. Firmware: unchangeable instructions that are executed when computer first boots up. These instructions are located in ROM (read -only memory), and contain basic hardware sequences which cannot be altered because they are permanently etched into a physical chip Software: n n Applications (e. g. Word, Excel, Internet Explorer) System Software / Operating Systems (e. g. Any version of Windows)

Processing pt 2 The processor follows this basic cycle: n n FETCH DECODE EXECUTE STORE The cycle starts again when the next command is fetched.

Storage Information can be stored in volatile or non -volatile memory. n n Volatile memory (basically RAM) is fast but if the power goes, all the data is lost. Non-volatile memory is slower, but the data persists even after you power down your computer. Examples: DVD disks, CDs, floppy disks, hard drives

Output occurs any time information is passed from the computer to an external device Examples: n n n A file prints on the printer A page is displayed on the monitor A signal is sent over a modem or network card

The Book vs. Me System Cabinet? ? ? 10. 8 Gig = $120 in 2001 120 GB = $120 in 2002 120 GB = $75 in 2004 120 GB = $59 in 2005 Building your own computer IS cheaper… n Until you factor in bad parts, repairs, system conflicts, your time, and frustration