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Chapter 4

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imissyou419's version from 2017-03-02 02:09

Section 1

Question Answer
ENIACfirst reprogrammable general-purpose computer, bootstrapping the computer
FERUATfirst digital computer in Canada
LAN Technologylocal area network - Ethernet was a set of rules, or protocols, enabling devices to communicate and share information, allowed many PCs to connect (small area)
WAN wide area network - internet
Invention of transistorssingle greatest invention in the 20th century; originally designed to be used as an airborne radar
MicrochipIntel 8800 microchip was used to make the first home computer & started a revolution
Overwhelming response to the Altair led to 3 major events:1. creation of microsoft (1975), 2. creation of Apple II (1977), creation of IBM PC (1981)
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Section 2

Question Answer
Mainframesfirst commercial digital computers which were large room sized devices based on now obsolete vacuum tube technology
Microcomputersdidn't have display or monitor, required users to develop their own programs
Hardwareconsists of physical electronic components and related gadgetry that input, process, output, and store data according to instructions encoded in computer programs or software
Input exampleskeyboard, mouse, scanner, UPC reader, microphone, touchscreen
Process examplesCPU, main memory, special function cards
Output examplesVideo display, printer, speakers, slide projector, plotter
Storage examplesmagnetic disk, optic disk, magnetic tape, SSD used in USB (universal series bus)
Processing devicesinclude CPU (central processing unit), selects instructions, processes them, performs arithmetic, logical comparisons and stores results of operation in memory
HertzGhz = 1 billion cycles/s, measures CPU performance
Main memoryalso referred to as RAM (random access memory), CPU works in conjunction with it, CPU reads data and instructions from RAM and stores the results in main memory
Storage hardwaresaves data and programs
USBexpensive, no moving parts, less power, generate less heat, less susceptible to mechanical failure; disadvantage is tending to complete fail with no prior indication
Special function devicesdevices that can be added to the computer to augment the computer's basic capabilities e.g. video cards added to support an additional monitor, co-processors for high-end math, extra storage
Binary digitsused to represent data, also called bits (0 = open switch or 1 = closed switch or 0 = one direction magnetic field, 1 = opposite direction magnetic field, 0 = no reflection, 1 = reflection for optic media)
Kb1024 bytes
Mb1024K
Gb1024Mb
Tb1024 Gb
Pb1024Tb
byte8 bit
Data channel/busby which the CPU reads instructions and data from main memory and writes data into main memory (moves instructions from main memory into CPU via this)
CacheCPU has small amount of very fast memory called this; a file on a domain name resolver that stores domain names and IP addresses that have been resolved, when someone else needs to resolve the same domain name, there is no need to go through entire resolution process
Operating System (OS)computer program that controls the computer's resources as well as a block of data
tend to be large and complicated programs that control the computer's resources, e.g. windows,
each version of an operating system is developed for a particular type of hardware,
specific instruction set that the CPU can process
Memory swappingmovement of programs and data into and out of memory,
if a computer has insufficient memory for its workload, swapping will degrade system performance
Volatiledata will be lost when computer or device isn't power e.g. main memory, cache
Nonvolatilememory that prevents data contents loss even when its not powered e.g. USB, magnetic, optic disk;
you can turn computer off and back on and content won't change
Client computersa computer that provides words processing, spreadsheets, database access, and a network connection
Serverscomputers that provide services;
used to publish websites, sell goods, host databases, support printing;
faster, larger, more powerful than client computers
Server Farma large collection of computers that coordinate all activities,
used for commercial websites: Amazons or Google
Cloud computingCustomers don't have to own the computer infrastructure, instead hardware, software, applications are provided as a service, usually through a web browser;
Cloud is a metaphor for the internet, which makes software and data service available from any location at any time
Computering software catagorized into 2 varieties:operating systems, application software
Application softwareprograms that perform specific user tasks,
applications are written to use a particular operating system
consists of programs that perform a business function
- can be general: excel, word
- can be specific: quickbooks (application that provides general ledger)
What are the 4 major operating systems?Microsoft Windows, Mac OS, Unix, Linux
Microsoft windowsMost common, focuses on software aspect of its business by licensing its operating system across a broad array of manufacturers
MacOScontrols all aspects of its computer systems - only available from Apple, hindered Apple's growth initially but kept company's products within a core group of graphic and art communities;
In 2006, moved to Intel-based architecture allowed Apple computers to also run Windows and an intense focus on design led to its resurgence
Unixoperating system has been workhorse of scientific and engineering communities, difficult to use, need to know arcane language for manipulating files and data
Linuxdeveloped by open-source community (no fee to use it), runs on client computers but mostly used for servers and web servers;
IBM is primary proponent
License- An agreement that stipulates how a program can be used
- Also the # of computers on which the program can be installed and # of users that connect and use
- stipulates limitations on liability of software vendor for consequences of errors in software
Horizontal market applicationsSoftware that provide capabilities common across many organizations and industries
Targeted at individual consumers
e.g. Word processors, graphic programs
Vertical market applicationsSoftware that serves the need of a specific industry
Can be altered or customized
The company that sold the application software either provides customization services or offer referrals to do so
Used by at automechanics and dental offices to keep customer data
One-of-a-kind applicationsoftware developed for a specific, unique need e.g. CRA develops software to audit tax return
Customer relationship management (CRM) softwarehorizontal application because every business has customers but needs to be customized to the requirements of a business in a particular industry so also has vertical market software
Off the shelfcommercial software
Off the shelf with alterationscommercial software that has been modified for a particular organization
Tailor madeaka customer-developed software, software adapted to particular organization's need
Firmwarecomputer software that is installed into devices such as printers, game controllers;
coding similiar to other software but installed into special, ROM (read-only memory) of the device,
program becomes part of device's memory, program's logic is designed into device's circuitry, users don't need to load firmware software,
referred as utility software,
can be changed or upgraded,
other e.g. disk optimization, data encryption, file and data recovery, disk image, security software, uninstaller software
Basic Input/Output System (BIOS)piece of firmware,
used when a computer is initially started or booted up,
required because all volatile memory is lost when computer shuts down, provide set instructions in nonvolatile ROM, first thing the computer does is load BIOS from ROM and run through commands provided by the firmware. BIOS checks to makes sure memory and input devices are functional, operating system loaded
Thin clientapplication that require nothing more than a browser,
e.g. Hotmail
Thick clientapplication that require programs other than a browser on the user's computer;
provides features and functions that more than compensate for expenses and administrations of its installation;
Does not need access to network to run
e.g. Microsoft Outlook
Thin & thick refer toamount of code that must run on client computer (e.g. thick has client-email software)
Client Hardwarespecify CPU speed, size of main memory, size of magnetic disk, CD or DVD & type, monitor type & size, # monitors
Server Hardwarebusiness manger has no role in specification of server hardware
Client Softwarespecify: Windows, Mac, Linus, PC applications, browsers, requirement for client side of client-server applications, need for thin or thick client
Server Softwarespecify requirements for server side of client-server application, work with technical personnel to test and accept software
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Question Answer
Virusa computer program that replicates itself
unchecked replication
virus consumes the computer's resources, take unwanted & harmful actions
PayloadProgram code that causes unwanted activity
Can delete programs or data or modify data in ways that are undetectable to user
Macro-virusAttach to Word, Excel, and other docs
When infected docs is opened, virus places itself in the start up files of the application, virus then infects every file the application creates or processes
WormVirus that propagate using internet or computer network
Spread faster than other viruses - specifically programmed to spread using networks (do not have to wait users to share a file with a second computer)
ZombieComputers infected with the worm or virus that infected an initial computer
BotnetA set of computers and applications that are coordinated through a network and used to perform malicious tasks
PatchesProgram modifications to fix the problems
A group of fixes for high priority failures that can be applied to existing copies of a product
Software vendors supply patches to fix security and other critical problems
System vulnerabilitiesTypical weaknesses in a system design that can be exploited by knowledgeable people
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