Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Chapter 1 Looking Inside the Computer System

1B-2 Parts of the Computer System Computer systems have four parts –Hardware –Software –Data –User

1B-3 Parts of the Computer System Hardware –Mechanical devices in the computer –Anything that can be touched Software –Tell the computer what to do –Also called a program –Thousands of programs exist

1B-4 Parts of the Computer System Data –Pieces of information –Computer organize and present data Users –People operating the computer –Most important part –Tell the computer what to do

1B-5 Information Processing Cycle Steps followed to process data Input Processing Output Storage

1B-6 Essential Computer Hardware Computers use the same basic hardware Hardware categorized into four types

1B-7 Essential Computer Hardware Processing devices –Brains of the computer –Carries out instructions from the program –Manipulate the data –Most computers have several processors –Central Processing Unit (CPU) –Secondary processors –Processors made of silicon and copper

1B-8 Essential Computer Hardware Memory devices –Stores data or programs –Random Access Memory (RAM) Volatile Stores current data and programs More RAM results in a faster system –Read Only Memory (ROM) Permanent storage of programs Holds the computer boot directions

1B-9 Essential Computer Hardware Input and output devices –Allows the user to interact –Input devices accept data Keyboard, mouse –Output devices deliver data Monitor, printer, speaker –Some devices are input and output Touch screens

1B-10 Essential Computer Hardware Storage devices –Hold data and programs permanently –Different from RAM –Magnetic storage Floppy and hard drive Uses a magnet to access data –Optical storage CD and DVD drives Uses a laser to access data

1B-11 Software Runs The Machine Tells the computer what to do Reason people purchase computers Two types –System software –Application software

1B-12 Software Runs The Machine System software –Most important software –Operating system Windows XP –Network operating system (OS) Windows Server 2003 –Utility Symantec AntiVirus

1B-13 Software Runs The Machine Application software –Accomplishes a specific task –Most common type of software MS Word –Covers most common uses of computers

1B-14 Computer data Fact with no meaning on its own Stored using the binary number system Data can be organized into files

1B-15 Computer users Role depends on ability –Setup the system –Install software –Mange files –Maintain the system “Userless” computers –Run with no user input –Automated systems

Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education 5. The Motherboard the motherboard, and its associated components.

Intro to CS. 5/Mother 17 Powersupply CD-ROMdrive Floppy disk drive Hard disk drive Wires and ribbon cables Sound/networkcards 1. Inside a PC Motherboard

Intro to CS. 5/Mother 18 The most important part of a PC is the motherboard. It holds: –the processor chip –memory chips –chips that handle input/output (I/O) –the expansion slots for connecting peripherals Some chips are soldered onto the motherboard(permanent), and some are removable (so they can be upgraded). 2. The Motherboard

Intro to CS. 5/Mother 19 Random Access Memory (RAM) chips. Expansion slots Motherboard Picture Read-only Memory (ROM)chips Processor chip (the CPU)

Intro to CS. 5/Mother 20 A data bus (a data path): connects the parts of the motherboard. Moving Data RAM via expansion cards

Intro to CS. 5/Mother 21 Random Access Memory (RAM). RAM is used to hold programs while they are being executed, and data while it is being processed. RAM is volatile, meaning that information written to RAM will disappear when the computer is turned off. 3. RAM continued

Intro to CS. 5/Mother 22 RAM contents can be accessed in any (i.e. random) order. By contrast, a sequential memory device, such as magnetic tape, forces the computer to access data in a fixed order because of the mechanical movement of the tape.

Intro to CS. 5/Mother 23 Each RAM location has an address and holds one byte of data (eight bits). RAM Storage

Intro to CS. 5/Mother 24 Computers typically have between 64 and 512 Mb (megabytes) of RAM. RAM access speeds can be as fast as 8 nanoseconds (8 billionth of a second). The right amount of RAM depends on the software you are using. You can install extra RAM. How much RAM is Enough?

Intro to CS. 5/Mother 25 Read-Only Memory can be read but not changed. It is non-volatile storage: it remembers its contents even when the power is turned off. ROM chips are used to store the instructions a computer needs during start-up, called firmware. Some kinds of ROM are PROM, EPROM, EEPROM, and CD-ROM. 4. ROM

Intro to CS. 5/Mother 26 A computer needs a semi-permanent way of keeping some start-up data –e.g. the current time, the no. of hard disks –the data may need to be updated/changed CMOS memory requires (very little) power to retain its contents. –supplied by a battery on the motherboard 5. CMOS Memory the battery

Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Chapter 1B End of Chapter