Chapter 1Chapter 1

Computer BasicsComputer Basics

What is a Computer?What is a Computer?

Functional definitions (45%)Functional definitions (45%)

Humorous definitions (5%)Humorous definitions (5%)

Academic definitions (45%)Academic definitions (45%)

Other (5%)Other (5%)

Functional DefinitionsFunctional Definitions

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

Humorous DefinitionsHumorous Definitions

““A computer is a machine that does what A computer is a machine that does what the operator tells it to do.”the operator tells it to do.”

““A computer is a thing that always crashes A computer is a thing that always crashes right when you’re in the middle of an right when you’re in the middle of an important assignment.”important assignment.”

““A porn box.”A porn box.”

Humorous? DefinitionsHumorous? Definitions

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

Academic DefinitionsAcademic Definitions

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

Academic DefinitionsAcademic Definitions

Classical academic definition:Classical academic definition: ““A computer is any device that receives input, A computer is any device that receives input,

processes that input, and produces output.”processes that input, and produces output.”

In everyday life, this is too broadIn everyday life, this is too broad Computers are electronic devices that primarily use Computers are electronic devices that primarily use

binary logic and integrated circuitrybinary logic and integrated circuitry They carry out a given task by executing a certain They carry out a given task by executing a certain

series of steps, according to programming, either in series of steps, according to programming, either in hardware or softwarehardware or software

They have a clearly distinguishable central processing They have a clearly distinguishable central processing unit which handles the computationunit which handles the computation

ComputersComputers

For most of what we talk about in this course, we’ll For most of what we talk about in this course, we’ll assume we’re talking about desktopsassume we’re talking about desktopsThe primary division in a desktop computer is hardware The primary division in a desktop computer is hardware vs. softwarevs. software

HardwareHardware: The physical (tangible) devices or : The physical (tangible) devices or components that make up a computer system. components that make up a computer system. SoftwareSoftware: The programs (intangible sequences of : The programs (intangible sequences of instructions) that a computer system runs.instructions) that a computer system runs.

The easiest way to tell the difference between hardware and The easiest way to tell the difference between hardware and software is to kick it.  If it hurts your toe, it's hardware.software is to kick it.  If it hurts your toe, it's hardware.

-- Carl Farrell-- Carl Farrell

A Typical Desktop Computer A Typical Desktop Computer

The The System UnitSystem Unit

Houses the following:Houses the following: CPU (Central Processing Unit)CPU (Central Processing Unit) RAM (main memory), RAM (main memory), hard disk drives (e.g. C: drive)hard disk drives (e.g. C: drive) floppy drives (e.g. A: drive)floppy drives (e.g. A: drive) other drives (e.g. CD-ROM, DVD)other drives (e.g. CD-ROM, DVD) also holds slots for various cards (e.g. network card, also holds slots for various cards (e.g. network card,

sound card, video card).sound card, video card).

Do not call it a “system cabinetDo not call it a “system cabinet””

PeripheralsPeripherals

A peripheral is any part of the computer A peripheral is any part of the computer external to the system unitexternal to the system unit

Peripherals allow communication between Peripherals allow communication between external sources (e.g. you) and your external sources (e.g. you) and your computer. computer.

Examples: Examples: mouse, keyboard, monitor, speakers, digital mouse, keyboard, monitor, speakers, digital

camera, printer, scanner, etc.camera, printer, scanner, etc.

Types of ComputersTypes of ComputersSupercomputersSupercomputers

can cost millions of dollars can cost millions of dollars perform perform trillionstrillions of operations per second of operations per second may have hundreds of thousands of CPUs may have hundreds of thousands of CPUs

MainframesMainframes Central computing units used by organizations (e.g. banks, airlines, insurance Central computing units used by organizations (e.g. banks, airlines, insurance

companies). companies). Can support 100s of users connected via Can support 100s of users connected via terminalsterminals. .

WorkstationsWorkstations Scientific, engineering, mathematical workhorses. Scientific, engineering, mathematical workhorses. Targeted toward a special-purpose task (e.g. numerical analysis, graphics Targeted toward a special-purpose task (e.g. numerical analysis, graphics

design). design). MicrocomputersMicrocomputers

PCs (Personal Computers) = desktop computers, PDAs (Personal Digital PCs (Personal Computers) = desktop computers, PDAs (Personal Digital Assistants), Laptops & Notebooks, Tablet PCs. Assistants), Laptops & Notebooks, Tablet PCs.

Microcontrollers (Embedded Systems)Microcontrollers (Embedded Systems) Computers embedded in "ordinary" systems. Computers embedded in "ordinary" systems. Control your TV, telephone, microwave, CD-Player, car airbags, .... Control your TV, telephone, microwave, CD-Player, car airbags, ....

What is Computing?What is Computing?

ComputingComputing is a 4-step sequence that is a 4-step sequence that turns raw data into useful information: turns raw data into useful information: InputInput ProcessingProcessing Storage (sometimes omitted)Storage (sometimes omitted) Output Output

InputInput

Input is when information is received from Input is when information is received from an outside source, such as:an outside source, such as:

A device: keyboard, mouse, modem, network card. A device: keyboard, mouse, modem, network card.

Memory: DVD movie, file on hard drive, CD Memory: DVD movie, file on hard drive, CD

ProcessingProcessing

Done in the CPU (Central Processing Unit)Done in the CPU (Central Processing Unit)The computer The computer executesexecutes millions (or billions) of millions (or billions) of very simplevery simple instructions per second. Examples include: instructions per second. Examples include:

FETCH a memory element. FETCH a memory element. FETCH another memory element. FETCH another memory element. ADD these memory elements together. ADD these memory elements together. STORE the result to memory. STORE the result to memory. These instructions form the computer’s program. These instructions form the computer’s program.

FirmwareFirmware: unchangeable instructions that are executed when : unchangeable instructions that are executed when computer first computer first bootsboots up. These instructions are located in ROM up. These instructions are located in ROM (read-only memory), and contain basic hardware sequences which (read-only memory), and contain basic hardware sequences which cannot be altered because they are permanently etched into a cannot be altered because they are permanently etched into a physical chip physical chip SoftwareSoftware: :

ApplicationsApplications (e.g. Word, Excel, Internet Explorer) (e.g. Word, Excel, Internet Explorer) System Software / Operating SystemsSystem Software / Operating Systems (e.g. Any version of Windows) (e.g. Any version of Windows)

Processing pt 2Processing pt 2

The processor follows this basic cycle:The processor follows this basic cycle: FETCHFETCH DECODEDECODE EXECUTEEXECUTE STORESTORE

The cycle starts again when the next The cycle starts again when the next command is fetched.command is fetched.

StorageStorage

Information can be stored in Information can be stored in volatilevolatile or or non-volatilenon-volatile memory. memory. Volatile memoryVolatile memory (basically RAM) is fast but if (basically RAM) is fast but if

the power goes, all the data is lost. the power goes, all the data is lost. Non-volatile memoryNon-volatile memory is slower, but the data is slower, but the data

persists even after you power down your persists even after you power down your computer. Examples: DVD disks, CDs, floppy computer. Examples: DVD disks, CDs, floppy disks, hard drivesdisks, hard drives

OutputOutput

Output occurs any time information is Output occurs any time information is passed from the computer to an external passed from the computer to an external devicedevice

Examples:Examples: A file prints on the printerA file prints on the printer A page is displayed on the monitorA page is displayed on the monitor A signal is sent over a modem or network A signal is sent over a modem or network

cardcard

The Book vs. MeThe Book vs. Me

System Cabinet???System Cabinet???

10.8 Gig = $120 in 200110.8 Gig = $120 in 2001

120 GB = $120 in 2002120 GB = $120 in 2002

120 GB = $75 in 2004120 GB = $75 in 2004

120 GB = $59 in 2005120 GB = $59 in 2005

Building your own computer IS cheaper…Building your own computer IS cheaper… Until you factor in bad parts, repairs, system Until you factor in bad parts, repairs, system

conflicts, your time, and frustrationconflicts, your time, and frustration