1 Computer Systems

A computer is...  A purely digital device  Definition: Digital is a type of electronic signal that is processed, sent and stored in bits—binary digits  Computers use binary coding—a coding system that uses two numbers--1 & 0  In computer terms, the bit is the smallest unit of measurement a computer can understand 2

Bits to bytes...  8 bits equal 1 byte  A byte is a single character of data, such as a letter, number, etc. 3 TermAbbreviationApproximate Size KilobyteKB or K=1000 bytes (actual size is 1024 bytes) MegabyteMB=1 million bytes GigabyteGB=1 billion bytes TerabyteTB=1 trillion bytes

A computer is device that...  Uses stored instructions (programs)  Accepts data that user supplies (input)  Manipulates data according to a program (processing)  Stores data (storage)  Produces results (output) 4

What types of data... ?  Text data – letters, numbers, and special characters  Graphic data – photographs, charts, and drawings  Audio data – voice and music  Video data – moving pictures and images 5

Computer systems  The physical components of a computer system are called hardware.  Hardware typically includes:  System unit, monitor, keyboard, mouse  Peripheral devices (extra) such as a printer or scanner 6

Computer system vs. System unit  Computer system—the system unit along with input and output devices  System unit—the part of a computer system that processes data and stores information 7

 Embedded  Smartphone  Handheld  Tablet  Netbook  Laptop  Desktop  All-in-One  Server  Mainframe  Super  Wearable Computer systems 8

Handheld Smartphone Netbook Tablet All-in-one Supercomputer Wearable Server Embedded Vehicle Laptop Mainframe

System unit  The main circuit board of a computer is the motherboard.  The central processing unit is located on the motherboard. The CPU is the circuitry that processes information—the “brain” of the computer.  The speed of the processor is controlled by the system clock. 10

System clock  Controls the timing of ALL computer operations; measured in hertz—one cycle per second. Speed is measured in gigahertz (GHz)—a billion cycles per second.  It takes about one-tenth of a second to blink your eye; a computer can perform some operations 10 million times in the time it takes you to blink you eye. 11

12 The most popular brand processors on the market are AMD and Intel.

Main memory  Main memory is located on the motherboard. It is also known as primary memory:  Random Access Memory (RAM)  Temporary memory available to the user; typically measured in gigabytes  Read Only Memory (ROM)  Permanent memory that handles basic startup functions, known as BIOS—basic input/output systems 13

Input Devices:  Any hardware component that allows a user to enter information into a computer  Keyboard  Pointing Devices  Scanners  Multimedia 14

Keyboards Solar Ergonomic-Split Flexible Blue-Tooth / iPadErgonomic-Split Child’s Toddler Wireless Gaming Virtual LED-Color Changing

Pointing devices:  Mouse  Trackball  Touch pad —typically found on laptops  Pen input —pen-like device touches surface of screen to digitally input data  Touch screen —touching the screen with your finger digitally inputs data 16

Scanners  Bar code reader—reads universal product codes (UPC)  Optical mark reader (OMR)—reads “bubble” sheets marked with pencil  Optical character reader (OCR)-reads handwritten or typed text  Page scanner—digitally captures an image or text 17

Multimedia  Microphone  Electronic music keyboard  Video camera  Digital camera  Virtual reality devices 18

Output device  Any hardware component that can convey information to the user  Display devices (soft copy: data projected on a screen)  Printers (hard copy: data printed on paper)  Speakers 19

Display devices 360° Pico Projector HDTV Flat-Screen Monitor Projector Interactive Whiteboard Document Projector

Printers  The two most common types of printers are ink-jet and laser  The speed of a printer is measured by the number of pages per minute (PPM) that can be printed  The quality of a printer is measured by the number of dots per inch (dpi) that can be printed 21

Storage devices  The media on which data and information are kept  Three classifications:  Magnetic—hard disk  Optical—CD, DVD, Blu-ray  Information is burned on the disk by laser  Flash—memory cards, flash drive 22

Communication devices  Devices that make it possible for a user to communicate with another computer  Most popular: modem  Phone, cable, DSL  Computers on a network use network interface cards (NIC)  Wired or wireless 23

 KB  MB  GB  TB  CPU  PPM  NIC  DPI  RAM  ROM  UPC  OMR  OCR Abbreviations 24  Mbps  Hz  GHz  HDTV  USB  PC