Intro to Information Technology

Intro to Information Technology • Wednesday, September 18th • Chapter 11 – Computer Hardware • Sites of Interest • www.ebay.com • www.microsoft.com • www.pcwebopaedia.com

Objectives • Identify the major types, trends, and uses of microcomputer, midrange, and mainframe computer systems. • Outline the major technologies and uses of computer peripherals for input, output, and storage. • Identify and give examples of the components and functions of a computer system. • Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selections

First Generation Second Generation Third Generation Fourth Generation Fifth Generation Trend: Toward Smaller, Faster, More Reliable, and Less Costly Vacuum Tubes Solid-State Integrated Circuits LSI, VLSI Micro- processors Greater Power, Smaller Footprint Trend: Toward Easy to Purchase, and Easy to Maintain History of Computers

The 1970s • 1971 – Intel makes the first microprocessor at a speed of 108 kHz • The UNIX operating system was written in the new language, C • One of the first personal computers, the Altair, came in a kit and you had to build it yourself • 1976 – The Cray-1, the worlds fastest supercomputer • 1977 – The debut of the Apple II, the first computer to have color graphics

The 1970s continued… • 1977 – The debut of the Apple II, the first computer to have color graphics • The Apple II had 4 KB of RAM and cost $1298 • The Commodore PET began the line of lost cost Commodore PCs • The VAX architecture was introduced in 1977 and cost $200000 • VisiCalc, the first spreadsheet program was created for the Apple II and it was the father of all productivity software

The 1980s • 1982 – IBM launched its first PC, powered by DOS, written by a tiny company named Microsoft • Xerox Alto – the first graphical user interface, went on to influence Apple and Microsoft • 1982 – Commodore 64 brought affordable personal computing to the masses • 1984 – The Apple McIntosh • 1984 – WordPerfect – the first word processor

The 1980s continued • 1985 – The first multimedia computer, the Commodore Amiga • 1986 - The Intel 80386 Processor, the first 32 bit processor • The C++ programming language • The Apple McIntosh II – the first color graphics McIntosh computer • The birth of 3D graphics

The 1990s • Microsoft Windows 3 – made PCs as easy to use as Apple McIntosh • Apple sues Microsoft over the similarity of the graphical user interface • AMD 386 – first processor not built by Intel • Virtual Reality

The 1990s continued • 1992 – Linux is created • 1993 – The Intel Pentium processor • The World Wide Web • Windows 95 was introduced after 18 months of marketing • E- Business and E-Commerce

Mainframe Computers Midrange Computers Microcomputers Computer System Categories • Microcomputers • Midrange Computers • Mainframe Computers

Microcomputers • The most important category for business people and consumers • Usually referred to as a personal computer (PC) • Types are handheld, notebook, laptop, desktop, etc • Microcomputers can perform tasks such as complex mathematical calculations, graphical applications such as computer-aided design, etc

Microcomputers • Network computers • Thin client – means a minimum of programs and processing occur on the machine itself • Software, data storage, and operating system are provided by the Internet and accessed through a browser • Usually does not have a local hard drive

Microcomputers • Information Appliances • PDAs – Personal Digital Assistant • These have touch screens, use a stylus for handwriting recognition, and are usually very small (hand-held) • Other appliances exist such as WebTV which allows you to surf the net from your TV

Microcomputers • Computer Terminals • Can be dumb (limited processing) or intelligent (more processing) • Intelligent terminals are found in areas such as transaction terminals, found in banks, stores, factories, etc • Capture data on terminal, and data is managed and processed by servers or other computers on the network

Midrange Computers • Multi-user systems that can manage networks of PCs and terminals • They are less powerful than mainframes, but more affordable • Used for such tasks as network management, data warehouse management, and assisting mainframes with telecommunications, etc

Mainframe Computers • Large, fast, powerful • Large storage capacities • Used to handle processing needs for major corporations and government agencies • Used for scientific calculations • Supercomputers – can have more than one processor

Parts of a Computer • Processing • Input • Output • Memory • Data Storage

Central Processing Unit Control Unit ALU Output Devices Output Devices Input Devices Special Purpose Processors Primary Storage Cache Memory Secondary Storage Devices A Computer System

Processing • The heart of the computer is the Central Processing Unit (CPU) • Two main divisions • Control Unit – Interprets instructions and directs processing • Arithmetic-Logic Unit – Performs arithmetic operations and performs comparisons • Also includes circuitry for registers and cache memory for high speed, temporary storage

Processing • The clock • This is what controls the processing in the CPU and at what speed it runs • With every clock tick, the CPU executes an action • Speed • Usually expressed in cycles per second, or hertz. • Today’s computers have speeds expressed in megahertz (MHz), a million cycles per second, or gigahertz (GHz), a billion cycles per second

Processing • Buses • Circuitry paths that interconnect microprocessor components for movement of data and instructions • ISA Bus • Industry Standard Architecture • PCI Bus • Peripheral Component Interconnect • Used to connect peripheral devices

Processing • USB • for Universal Serial Bus, an external bus standard that supports data transfer rates of 480 Mbps (480 million bits per second). A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards • AGP • for Accelerated Graphics Port, a new interface is based on PCI, but is designed especially for the throughput demands of 3-D graphics • Definitions from www.pcwebopaedia.com

Processing • Since CPUs generate a lot of heat, a cooling mechanism is needed • A metal heat sink is placed over the processor. It draws the heat out into its spikes • A fan on the heat sink blows the hot air away from the processor

Input • Keyboards • Can easily type in instructions • Mouse • Enables the user to point and click • Works with a graphical user interface for easy navigation • Trackball • Similar to a mouse, but you move the ball • Touchpad • Move your finger on the pad to move the cursor

Processing • Popular types of processors • Intel • Pentium, Pentium II, Pentium III, Pentium IV • Celeron • AMD • Athalon • Duron

Input • Touch screen • Users touch the screen to move the cursor or to make selections • Pen-based computing • Many hand-held devices use small pens to draw on the screen, or a designated area. • Speech Recognition • Users speak to a computer and it interprets their commands

Input • Optical Scanning • Read text or graphics and convert them into digital input for the computer • Reflected light patterns of the data are converted into electronic impulses that are accepted as input • OCR or optical character recognition can be used to read codes or characters such as UPC codes

Input • Magnetic Stripe • Iron oxide coating holds up to 200 bytes of information • Digital Cameras • Can take pictures and load them on to your computer • Magnetic Ink Character Recognition • Used on cheques for banks to sort and process cheques

Input • Serial Ports • This is how keyboards and some older mice connect with the computer • Only 1 bit of information is transmitted at a time • PS/2 Ports • Mice or keyboards connect to computers with this type of port] • Developed to free up a computers serial port • Most new devices use USB ports because of their high speeds of data transfer and one port can connect up to 127 devices

Output • Video • Video monitors use CRT (Cathode Ray Technology) similar to TVs • Liquid crystal displays (LCD) are usually used for portable computers • LCD gives a flat screen with bright colours and clarity • LCD displays need less electric current and have a thin, flat display

Output • Video continued… • The quality of the video display can depend on the type of video card that is used • Video cards can be plugged into either a PCI or AGP bus • They have their own storage, now usually between 16 and 32 MB • Resolution settings also depend on the video card • Most common resolution on a 15” monitor is 800X600, which is the screen size measured in pixels

Output • Printers • Dot Matrix • Old style of printers than printed across the page one line at a time • Very slow printing • Inkjet • Spray ink on to a page one line at a time • Popular, low cost personal printers • Good quality and fairly quick printing

Output • Printers continued… • Laser • Use an electrostatic process similar to a photocopier • Fast, high quality output in black and white • Colour is very expensive • Popular for businesses • Popular printer brands include HP, Canon, Lexmark, and Epson

Output • Printers were traditionally connected to the computer by a parallel port • Parallel ports have 25 pins and transmit more than one bit per second (unlike serial ports) • Now many printers connect through the USB bus

Memory • Sizes of memory • One Bit – one character, either a one or a zero. • This is the simplest information that a computer can process • Binary expresses data in terms of a sequence of 1’s and 0’s • 1’s and 0’s correspond to On/Off, True/False, +5 volts/0 volts

Memory • Sizes of memory continued… • A byte is 8 bits • A nibble is 4 bits • A KB, or kilobyte, is 1024 bytes • A MB, or megabyte, is 1024 kilobytes • A GB, or gigabyte, is 1024 megabytes

Memory • RAM – Read Only Memory • This can also be referred to as direct memory • Each storage position • Has an unique address • Can be individually accessed in the same amount of time without having to search through other storage positions • Is used for data that needs to be retrieved quickly • Is used during the running of applications • Storage capacity is expressed in MB (megabytes)

Semiconductor Memory Primary Storage Direct Access Magnetic Disks Floppy Disk Hard Disk, RAID Access Speed Increases Storage Capacity Decreases Cost per Bit Increases Magnetic Tape Sequential Access Secondary Storage Optical Disks CD-ROM, CD-R CD-RW DVD Direct Access

Memory • Primary storage (main memory) of a computer consists of semiconductor memory chips • Semiconductor memory has a small size, great speed, and shock and temperature resistance • Provides working storage for your applications • One disadvantage is that is requires a constant supply of uninterrupted electrical power

Memory • RAM continued… • Usually machines today come with between 128 and 256 MB of RAM • RAM is an important factor in how fast your computer runs applications • More RAM is needed for applications that need a lot of temporary storage, such a photo-processing applications, and 3D games • RAM is volatile i.e. the contents are lost as soon as power to the memory is interrupted

Memory • ROM – Read Only Memory • This memory can only be read, not erased or overwritten • Control instructions and low level programs can be burned into this memory during manufacture • This is also known as firmware • This memory is non-volatile i.e. it doesn’t require power to keep the contents in memory

Memory • L2 Cache • As discussed earlier, the processor has a small amount of storage right on the chip • A Level 2 Cache is memory external to the processor, it is stored on a chip outside the processor • Now manufacturers are starting to build L2 caches right on the chip

Data Storage • Need to backup contents of main memory so information is not lost when the power is shut off • These devices and technologies are known as secondary storage • Three common types are • Magnetic disks • Magnetic tape • Optical disks

Data Storage • Magnetic disks • Fast access and high storage capacity for a reasonable cost • Magnetic disk drives contain metal disks that are coated on both sides with a iron oxide recording material • These disks are mounted on a vertical shaft that rotates them at speeds of between 3600 – 7600 rpm

Data Storage • Magnetic disks continued • Electromagnetic read/write heads are positioned on arms between the disks to read and write data in concentric circles • Data is recorded as tiny magnetized spots to form binary digits that the computer can read • Disks have billions of storage positions

Data Storage • Magnetic Disks continued… • Floppy disks • Polyester film disks coated with iron oxide • Rotates inside a plastic jacket • Most common floppy disk is the 3 ½ inch disk than can hold 1.44 MB of data

Data Storage • Magnetic Disks continued… • Hard Disk • Combine magnetic disks, access arms, and read/write heads in a sealed module • This allows higher speeds, greater data recording densities, and closer tolerances • Hard drives can usually store up to many gigabytes of data • Hard drives are where the operating system and applications are permanently stored

Data Storage • Magnetic Disks continued… • RAID – Redundant arrays of independent disks • Replace large capacity mainframe disk drives • Many interconnected microcomputer hard disk drives provide large capacities with high access speeds since data is accessed in parallel • If one disk fails, data can be recovered from one of the others

Data Storage • Magnetic Tape • Data is recorded on the iron oxide coating of the magnetic tape • Can hold over 200 MB of data • Most commonly used for backup storage and archival of data • This is a low-cost technology that supplements magnetic disk storage

Tracks: Concentric circles for storing data as magnetized bits. Cylinders Access Mechanism Disks Access Arms Track Read/Write Heads Sectors: Portions of a track

Intro to Information Technology