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CS-155 Part 2

liz simpson Inglés 159 fichas

Fichas del conjunto (159)

1what does the file command tail dodisplays the last 10 lines of a file
2what does the file command less do?view and paginate a file
3What does the file command more do?view and paginate a file (although has fewer options than less)
4What does IO Redirection do?Allows you to send the output commands to files, or other commands
5IO Direction commandscmdfile standard output of cmd to file
cmd >>file append stout to file
cmd1|cmd2 pipe cmd1 output into cmd2
6What is a flagmodify performance of command
7-rreverse order
8-RRecursive (inc subdirectories)
9name flags
10what are permissions3 digit numbers that covers owner, group, and everyone privileges
11How to calculate permissions
12What are wildcard and their symbolsallow selection of files with similar names
? -when one char changes
*-used when a group of chars can vary
[]-specify a range of values
{}-specify a set of values
13Process controls
14Section 5Networks
15Define a computer networkA collection of computing devices connected in order to communicate and share resources
16How can computers be connected in a network?either physical wires or cables. Or wireless using radio waves or infrared signals
17What are two important characteristics of a networkautonomous - governs itself
interconnected
18What are the two objectives of a network?Share expensive resources
sharing and exchanging data
19what is the speed of a token ring / token bus?1-5 Mbps
20Whats the speed of Ethernet (CSMA/CD)10 Mbps
21What's the speed of FDDI (Fibre Distributed Data Interface), Fast Ethernet100 Mbps
22What's the speed of ATM (Asynchronous Transfer Mode)600 Mbps
23What's the speed of Gigabit Ethernet, Multi-Fibre-Chnanels1-10 Gbps
24how many bits are in kilo, mega, giga, tera, peta and name a use10^3 - user interaction
10^6 - lazer printing
10^9 Digital TV
10^12 3D TV
10^15 ?
25Define Nodeany device on a network
26Define Data Transfer Rate (bandwidth)The speed with which data is moved from one place to another on a network
27Define a ProtocolA set of rules which govern how data is formatted and processed on a network
28Define File ServerA computer that stores and manages files for multiple user on a network
29Define Web ServerA computer dedicated to responding ti requests (from the browser client) for web pages
30Name 3 types of networksLAN
WAN
MAN
31Define a LANLocal Area Network - A network that connects a relatively small number of machines in a relatively close geographical area
32What are three types of LAN network topology?Ring
Star
Bus
33Describe a ring networkconnects all nodes in a closed loop on which message travel in one direction. If one node fails, all nodes fail.
34Describe a Star topologyAll nodes are connected to a central node, messages are sent to the central node.
35Describe a bus topologyNodes are connected to a single communication line that carrier messages in both directions
36What is a WAN?Wide Area Network - A network that connects local area networks over a potentially large geographical distance
37Describe a MAN?Metropolitan Area Network - The communication infrastructure that have been developed in and around large cities
38Describe a gatewayA gateway handles all communication between that LAN and other networks.
39What is the internetA WAN that spans the planet.
It has an Internet backbone that is a set of high speed networks that carry internet traffic, provided by comapnies like AT&T, BT, GTE, IBM.
Internet Service Porovider - a company that provides access to the internet.
40Whats the internet backbonethat is a set of high speed networks that carry internet traffic, provided by comapnies like AT&T, BT, GTE, IBM.
41what's an ISPa company that provides access to the internet.
42What are three different Internet ConnectionsPhone modem
Digital subscriber line
Cable modem
43How does Phone Modem connect to the internet?converts computer data into an analog audio signal for transfer over a telephone wire, and then modem at the destination converts it back to data
44How does digital subscriber line work?Uses regular copper phone line to transfer digital data to and from the company's central office
45How does Cable modem work?Uses the same line as cable TV to transfer data
46What is broadband?A connection with transfer speeds faster than 768kbps.
DSL connections and modem connections
The speed for downloads may not be the same speed as your uploads
47Define IMPInterface Message Processor
48Draw a typical network structure
49What are the two ways of network routingpacket switching
circuit switching
50Describe circuit switchingHaving a predetermined route for sending data. No-one else can use that path while you are transferring data.
51Describe packet switchingData is split up into numbered fixed sized packets and sent many ways through a network, packets may arrive out of order at the destination so must be reconstructed.
52Define PacketA unit of data sent across a network
53Define RouterA network device that directs a packet between networks toward its final destination
54What is a syntax protocol?governs data formats, and single level
55What is a semantic protocol?governs error handling, flow control
56What is a timing protocol?governs sequencing, synchronisation
57What is a protocol stack/hierarchyNetwork protocols are layered such that each one relies on the protocols that underlie it.
58Define a Proprietary SystemA system that uses technologies kept private by a particular commercial vendor
59Define InteroperabilityThe ability of software and hardware on multiple machines and from multiple commercial vendors to communicate
60Define open systemsSystems based on a common model of network architecture and a suite of protocols used in its implementation
61What is open systems interconnection reference modelA layered logical breakdown of network interaction to facilitate communication standards.
Each layer deals with a particular aspect of network communications
62What are the seven layers to the OSI Model?Applcation
Presentation
Session
Transport
Network
Data Link
Physical
63Draw a diagram of the OSI Model
64What does CSMA/CD stand for?Carrier Sense Multiple Access with collision detection
65What does carrier sense mean?means listening for the medium to be idle before trying to transmit. If the medium is free, send it.
66What does Multiple access meanAllows multiple deices share the medium. (so two devices could try and transmit at the same time)
67What is collision detectionIf two devices are waiting to send while a third transmitting. When the medium is idle both transmit, garbling messages so neither gets through (collision). The sending devices are listening for a collision by comparing signals.
68What happens when a collision is detectedThe transmitting machine stop sending data and sends a jamming signal, the jamming signal is to make sure the other machine has detected the collision. Then they both wait a random amount of time before re-transmtting
69What connection do LANS useEthernet connects one to +++ devices. Comes in cabes, wires, twisted pair....
70What behavior does Ethernet exhibitNon-deterministic
71what does deterministic behavior mean?behavior that can be accurately predicted.(no chance or variables involved)
72Why is Ethernet Non-deterministic in character?Because of collisions which cannot be predicted and the random back off time, Ethernet behavior is not predictable
73What does the ethernet protocol specify?How bits will be grouped for transmission
74What's included in ethernet protocolStarts - a special signal pattern that is used only for signaling the start of the fram.
DEST, SOURCE - destination and source addresses of machines on the network
T: type of frame (data or control)
Data: 46-1500 bytes
FRAME: frame checks for errors
75How long is the ethernet source/destination addresses. Why so many48 bits long. (256 trill)
allows manufacturers to be assigned different blocks of addresses, allows devices to be thrown away - no need to recover and reuse the address.
76Here's a diagram about internet protocols
77Define TCPTransmission Control Protocol - Software that breaks messages into packets, hands them off to the IP software for delivery, and then orders and reassembles the packets at their destination
78Define IPInternet Protocol - software that deals with the routing of packets through the maze of interconnected networks to their final destination.
79Define UDPUser Datagram Protocol - An alternative to TCP that is faster but less reliable
80Define PingA program used to test whether a particular network computer is active and reachable
81Define TracerouteA program that shows the route a packet takes across the Internet
82Name 4 high-level protocolsSMTP
FTP
Telnet
http
83Define SMPTSimple Mail Transfer Protocol - used to specify transfer of electronic mail
84Define FTPFile Transfer Protocol - allows a user to transfer files to and from another computer
85Define Telnetused to log onto one computer from another
86Example of telnet commands
87Define HTTPHyper text transfer Protocol, allows exchange of Web documents
88What's a port?A numeric designation that corresponds to a particular high - level protocol
89What does MIME stand for and do?Multipurpose Internet Mail Extension type.
A standard for defining the format of files that are included as email attachments or on websites
90What is a firewallA gateway machine and its software that protects a network by filtering the traffic it allows
91What is an Access Control PolicyA set of rules established by an organisation that specifies what types of network communication are permitted and denied
92What is a hostnameA name made up of words separated by dots that uniquely identifies a computer on the internet
93What is an IP addressAn address made up of four one-byte numeric values separated by dots that uniquely identifies a computer on the internet
94What does IPv4 do?address stored in 4 bytes
source address 32 bits
destination address 32 bits
95What does IPv6 do?8 groups of 16 bits (hex) .
source address (128 bits)
destination address(128 bits)
96Define Domain Name systemDNS - a distributes system for managing hostname resolution
97Define Domain name serverA system that attempts to translate a hostname into an IP address
98What's a host numberThe part of the IP address that specifies a specific organisation or group
99Top-Level DomainTLD - the last section of a domain name that specifies the type of organisation or its country of origin
100Name some top level domains.com
.edu
.gov
.net
.org
101Name some county codes.au
.uk
.ca
102ICANN 2011 - approved generic TLDs for brands and object.e.g. social
furniture
wiki
103Who controls the ID address and domain names of the internet?ARPANET - US Dept of defence.
Control subcontracted to ICANN
104What are FCC's proposal?-allowISPs to provide premium access to someby slowing access of others.
-Net Neutrality - the principle that ISPs should deliever data to everyone equally as fast as possible.
105What's domain squatting?Ransoming domain names
106Draw a diagram for FPT
107Draw a networked file system
108Draw a diagram of how emails work
109Name 4 modes of virtual terminalScroll Mode
Page mode
Form/data entry mode
graphics mode
110describe Scroll mode terminalsNo built in micro processors nor any local editing capability
111describe page mode terminalswith cursor and selection control, and often colour and intensity control.
112describe form/data entry mode terminalshave built - in microprocessors and allow forms being downloaded onto the screen and edited locally
113Describe graphics mode terminalsallow the creation of arbitrary 2D patterns
114What is a subnet maskA subnet mask is a number that defines a range of IP addresses that can be used in a network. ... A subnet mask hides, or "masks," the network part of a system's IP address and leaves only the host part as the machine identifier. A common subnet mask for a Class C IP address is 255.255.255.0
115draw a diagram of subnet masks
116Draw a diagram for HTTP
117Diagram for intermediate HTTP
118what are public cloud networks?accessible by any subscriber
119What are private cloud networks?established for a specific group or organisation
120what are community cloud networks?are shared amoung two or more organisations with the same needs
121What are hybrid clouds?some combination of others
122What are the advantages of wireless networks?cost - physical wires and installation are expensive and disruptive
Mobility and flexibility - convenient and only true mobile way.
123What are the disadvantages of wireless networks?speed - wireless are slower
security - anyone can listen in
safety - exposure to electromagnetic radiation
interference - communication susceptible to interference from other signals.
124What was Alohafirst really successful network (Hawaii)
125What is WIFIcollective names for networks based on a standard called IEEE 802.11
126What affects WIFI rangefurniture, other equiptment and walls.
Greater the range, slower the connection
127How does WIFI work?bus based broadcast network.
Monitors signal broadcasts by the access point.
-SSID (service set identifier) beacon packets every 100ms. at a slow but detectable rate.
128What are the 2 problems for wireless network-cant listen and send at the same time.
-you cant hear what the base station hears.
129over view
130Define the world wide webAn infrastructure of information combined and the network software used to access it
131define web pageA document that contains or references various kinds of data
132define linksa connection between one web page and another
133define websitea collection of related web pages
134define web browsera software tool that retrieves and displays web pages
135define wed servera computer set up to respond to requests for web pages
136define uniform resource locator (URL)a standard way of specifying the location of a web page, containinf / and a file
137define search enginea website that helps you find other websites
138define blog or weblogan online journal or newsletter that is frequently updated and intended for public consumption
139what is a cookiea small text file that a web server stores on your local computers hard disk. A cookie contains information about your visit to the site.
140what are the three ways cookies can be used?1. to determine number of unique visitors to the site
2.to customize the site for future visits
3. to implement shopping carts that can be maintained from visit to visit
141what are web analyticssome websites colect and analyse data on a website usage. To track the number and behaviors of users.
-geographically
-which site referred them
-which pages they visit
-time spent on page
-which page they leave your site from
142What is HTMLthe language used to make a web page
143define markup languagea language that uses tags to annotate the information in a document
144define a markup language "tag"the syntactic element in a markup language that indicates how info should be displayed. Enclosed in <>
145Name some elements from HTMLhead
title
body
146What does the browser dodetermines how the page should be displayed based on tags.
It ignores: format of HTML (blank spaces)
2. takes into account width and height
3. reformats the contents to fit your browser
147What is an attribute?Part of a tag that provides additional info about the elements
attribute name = value
148What is a link?a link is specified using the element A,(which stands for anchor) and attribute HREF that specifies the URL of the destination document
149In CSS, Styles can be .....specified at multiple levels and overridden at lower levels as needed
150What are the 4 rules of CSS1. setting margins to auto, centres the image horizontally
2. unvisited link in blue
3.visited link in gree
4. when mouse hovers over link, text purple and underlined
151HTML 5 Tagsnav elements on page
define primary content
define secondary content
define images
152How does HTML 5 support dynamic content?content loaded asynchronously to improve download speeds
153What is a java applet?program designed to be embedded into an HTML doc, transferred over the web and executed in browser.
executed on client machine
154what is a JPS scriptleta portion of code embedded in an HTML doc designed to dynamically contribute to the content of the web page.
executed on server
155What is a Java server page?a web page that has a JSP scriptlet interwoven amoung the HTML content. <% %>
Executed on the server
156What is XMLextensible mark up language.(metalanguage?)
XML represents a standard format for organising data without tying it to any particular type of output.
157Where are the tags for XML definedin the DTD document type definition.
specifies the organisation of the document
158what language do we use to transform XML to other formats?XSL (extensible stylesheet languge)
159r