Computer Systems 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

Bits to bytes . . . 8 bits equal 1 byte A byte is a single character of data, such as a letter, number, etc. Term Abbreviation Approximate Size Kilobyte KB or K =1000 bytes (actual size is 1024 bytes) Megabyte MB =1 million bytes Gigabyte GB =1 billion bytes Terabyte TB =1 trillion bytes

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

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

Computer systems Embedded Smartphone Tablet Laptop Desktop Server Mainframe Super Wearable

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.

System clock Controls the timing of ALL computer operations; measured in hertz—one cycle (tick) 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.

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

Memory: Main memory is located on the motherboard. It is also known as primary storage. Random Access Memory (RAM): Volatile memory available to the user; typically measured in Gigabytes. Read Only Memory (ROM): non-volatile memory that handles basic computer functions known as BIOS: Basic Input/Output Systems.

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

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

Scanners Bar code reader—reads universal product codes (UPC) Computer Systems 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 The second bar code is actually a QR (quick response) code, which is a variation of a bar code. 2d CODES: http://www.barcodeman.com/faq/2d.php

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

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

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

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

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