Course overview

These are some of the slides from presentations we covered this term.

Ive modified some of them a little and added a couple organzing slides.This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. CIS 275 f2010 greatest hits1IT literacyWhat skills and concepts are needed for success as a student and after graduation as a professional and a citizen?

John KemeneyThomas Kurtz2John Kemeney and Thomas Kurtz taught the first ever IT Literacy course at Dartmouth College during the first half of the 1960s.

Before that, only engineering and science students learned about computers, but Kemeney and Kurtz thought that every liberally educated person should be IT "literate."

Computers were far from mainstream in those days, but Kemeney and kurtz understood that they would become ubiquitous.

In designing their course, they asked what were the skills and concepts their students needed to succeed while in school and after graduation as citizens and professionals.

Kemeney worked on the Manhattan Project, was Einsteins mathematics assistant as a student, and was Professor of mathematics and President of Dartmouth College.

Kurtz studied under John Tukey at Princeton, has been professor of math, computer science and Computer Information Systems and computer center director at Dartmouth.-----

History of IT literacy: http://computerliteracy3.blogspot.com/search/label/history

Applications

ImplicationsTechnologyInternet concepts

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsIve organized the concepts into three groups those having to do with IT applications, implications and technology.

Applications are the things people do with computers and the Internet the things they use them for.

Implications are the ways information technology changes our individual lives, our organizations and society.

Just think of the ways you use computers and the Internet. How do they affect your life, organizations like your school and workplace and society as a whole?

Well also present technology concepts.

As the graph on the right show, all forms of information technology -- storage, communication and memory and processing are improving rapidly.

This rapid technology change will lead us to think about future applications and implications as well as those we see today.3

Skills

Content creationApplication development

User skillsInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsIve divided the skills portion of the class into three areas, creating and editing content, developing new applications, and using applications.

Technical progress has led to the simplification of all three.4

ApplicationsemailWeb searchPhone calls

ChatShopping

Music

VideoInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsThis slide shows some common applications, and I bet youve done most of them.

Have you made an Internet phone call or listened to music or watched a video?

I am sure youve sent and received email and searched the Web, and I bet youve shopped online and engaged in text or perhaps video chat.

Each application requires a program, and, if its a networked application, your computer must be connected to the Internet.

As we will see, the program may be installed on your computer or downloaded when you start to use it.

These programs are also often referred to as application programs or just apps.

Note that the computer you use these days may be portable a phone or tablet rather than a traditional laptop or desktop computer.5

Network-based applications

A relatively slow linkThe Internet(programs and data)Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills6We focus on network-based or network applications, either the program, the data or both are stored on the Internet.

Network vs. desktop applicationsDesktop or stand-aloneNetwork based

InternetInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsThere are, of course, many computer applications that dont involve the Internet for example, using Microsoft Word to write a document or Excel to make a spreadsheet.

In stand-alone applications, the program and data are both stored locally on your computer.

In our class, the focus will be on network-based applications in which the computer is connected to the Internet.

Remember, this is IT literacy for the Internet era.7Web data flow

WebserverprogramMemoryStorageRequestedpage

WebclientprogramMemoryDisplayRequestedpage

ClientServerRequestPageThe InternetInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills8This figure summarizes the data flow in retrieving a simple Web page one that does not contain any programs.

First the client sends a request for the page to the server.

When the server receives request, it finds the page in storage, then copies it to its memory

Then it sends the page across the Internet to the memory of the client computer.

The client then displays the page.

ClientServer

requestWeb page plus WP program

Retrieving a Web application programInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills9We saw that with a stand-alone application, both the application program and the data it works on are stored locally.

With a networked application either the program, the data or both are stored on the network.

The Google Docs word processing program is downloaded from Google and the documents you write are stored there too.

Networked programs are downloaded automatically when you visit their Web site.

The programs do not have to be complete application something as simple as a rollover menu can be programmed.I would like to open a connection

GET

Display responseClose connectionOK

Send page or error message

OKClientServerAn HTTP conversationInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills10This process involve a conversation between the client and server.

But, it is not an informal conversation, it is governed by strict, standardized rules.

The rules which specify the conversation between two computers are called protocols.

The protocol that governs the conversation between a Web client and a Server is called HTTP, the hypertext transfer protocol.

Information technologies

Processing and memoryStorageCommunication

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills11Broadly speaking, we process, store and communicate information.

Each of these changes rapidly through technology progress and technology shifts.Technology improvement and technology shiftsInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills12Technology progress occurs in two ways improving current technology and shifting to new technologies.

When we discover a technology, we continuously improve it over time.

Technology shifts occur when we move from one technology to another for example moving from punch cards to magnetic tape or disk for storage.

Lets look at two technology improvement examples and two technology shift examples.

The bottom lineInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsThe bottom line is that information technology is improving very rapidly.

Such drastic improvement leads to qualitative changes.

It is not just that we do the same things faster or cheaper; new technology enables us to do new things.

That means we will see changes in our individual lives, organizations and society as a result of progress in information technology.

13Computer componentsMemoryCPUStorage devices(programs and data)InputdevicesOutputDevicesInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills14Computer systems have five functional components, input, output and storage devices, memory and a central processing unit (CPU).

Keyboards and displays are common input and output devices.

Magnetic and optical disks and flash drives are used for storage.

The CPU and memory are small electronic chips inside the computer.

The arrows show the flow of information within the computer system.

The Internet is a very large, slow storage device

A relatively slow linkThe Internet(programs and data)Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills15You can think of the Internet as a large, low cost, but relatively slow storage device for every computer connected to it.

Today we use it to store relatively small programs and data files that dont require high speed access.

We store large programs and critical data on local devices like hard drives or flash drives.

Technological change will affect this balance between the Internet and local storage.

For example, faster Internet connections favor storing information in the cloud, and falling prices of local storage devices favors storing information locally.

SensorsInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsThe real world is analog, but computers are digital.

That means that when a computer interacts with the physical world getting input from a microphone, reading the temperature of a room, recognizing that it has been tilted or rotates, etc, analog data must be converted to digital.

If the computer wants to effect the outside world play sound, turn on a heater, etc. it must output analog data.16

100110101010011101100101Summary

Internet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsTo summarize, files consist of bits.

When a file is transmitted across the Internet, it is split into packets.

The packets are sent one at a time, and the receiving computer re-assembles them into a perfect copy of the original file.

The file can then be displayed, printed, stored or modified at the receiving end.

We also saw that the numeric IP addresses identifying the computers are difficult for people to recall, so we use domain names.17Connectivity from and within a LAN

The InternetHow does the LAN connect to the Internet?How are the computers connected inside the LAN?LANInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skills18Weve covered connectivity inside local area networks and connectivity from local area networks to the Internet.

Internet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsConnectivityWeve covered home, organization, mobile and portable and backbone connectivity.19Communication links

Computer 1Computer 2Internet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsWeve covered several characteristics of a data communication link the technology it uses and its speed, length, latency, jitter and packet loss rate.

We focused on speed, noting that it is measured as a quantity of data per unit of time.

Bits per second is a common unit of measure.

We also looked at some typical link speeds, and noted in passing that some links are asymmetrical faster in one direction than the other.

Finally, we saw that overall link performance is increasing world wide, but so is the gap between developed and developing nations.20Units of measure for data transmission rate TimesecondAmount of databitTransmission ratebits per secondTransmission rate = amount of data per unit of timeInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skills21Bits per second is a commonly used measure of data communication rate.

One could also use bytes per second, bits per hour, megabits per second or any other measures of the amount of data and time.

Conversion between them is just a matter of multiplying or dividing.

The route from one host to anotherInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsAs shown here, the data link layer is responsible for moving data from a particular host within a local area network to the router at its edge.

At that point, the Internet layer takes over and routes it across the Internet.

When it arrives at its destination network, the data link software delivers it across the LAN to the appropriate program on the destination host

The data link layer does error checking and correction within the LAN.

22Function of each layerLayerFunctionApplicationDo useful work like Web browsing, email, and file transfer TransportTransport data between application programs running on two hostsInternetRoute packets between networks (inter network)Data linkSend data within the local area networkPhysicalSpecify hardware characteristics and ways to differentiate between ones and zerosInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skills23Application layer software does useful work.

Transport layer software sets up and drops connections and is responsible for transport data between hosts. There are two transport layer protocols. One checks for errors and is reliable, the other just sends data and assumes it reaches its destination.

The Internet is a network of interconnected networks, and Internet layer programs are responsible for routing information from one network to the next as it moves across the Internet.

When an incoming data packet arrives at its destination local area network (LAN), a data link program gets it to the proper program on the destination host.

Similarly, the data link layer sends outgoing packets across the LAN to the router at its edge.

Physical layer programs are responsible for things like differentiating one bits from zero bits and controlling the communication hardware.Application(many)

Transport(UDP, TCP)

Internet(IP)

Physical(LAN, WAN links)

Data link(Ethernet, WiFi)

TCP/IP hierarchy -- protocolsInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsHere we see a hierarchical summary of the protocols used in general practice at each layer.

There are two choices at the transport layer TCP for reliable, error checked communication and UDP for unreliable communication.

There are also two common data link protocols Ethernet for wired connections and WiFi for wireless.

The physical layer falls outside the hierarchy, but the hardware must be compatible with the data link protocol used on a given link.

24Application(do useful work)

Transport(app to app communication)

Internet(net to net communication)

Physical(LAN, WAN links)

Data link(LAN communication)

TCP/IP hierarchy -- responsibilitiesInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsIt is traditional to present the TCP/IP layers in a stack on top of each other, as we have done above.

It might be more helpful to view them hierarchically.

Here we see the responsibilities or functions of the software at each layer.

Application programs use the transport layer for client-server communication.

The transport layer uses the data link layer to send data within the LAN and the Internet layer to send it across the Internet to the destination LAN.

The physical layer falls outside the hierarchy there is a hardware and software specification and implementation for every link.

This is analogous to an organization in which the boss (the application program) asks a subordinate (the transport layer software) to take care of a communication task.

The transport layer uses its subordinates, the Internet and data link layers to divide the work between them.

Note that the boss the application program is isolated from the implementation details, just as the boss is in an organization.

Just as the president of a company does not bother deciding whether to use UPS or FedEx for a shipment, an application program is not aware of whether a host is connected by fiber or wireless, is a Macintosh or PC, etc.25IP addresses and domain names65.55.12.249www.microsoft.com

65.55.12.249 = www.microsoft.comInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skills26Lets mention one more point.

People identify computers on the Internet using their domain names, names like som.csudh.edu or www.microsoft.com.

Those names are fairly easy for us to recall.

However, computers use numeric IP addresses like 65.55.12.249

IP addresses are easier for computers to work with than domain names.

We use domain names for computers, and they are converted to the equivalent IP address when a computer needs to use them.

We will see how that is done in another presentation.Implications for

IndividualsOrganizationsSocietyInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsHow does IT affect individuals, organizations and society as a whole?

Here we see a man working from home making obvious changes in his life.

How does the Internet affect your life or to put it another way, how would your life change if the Internet disappeared tomorrow?

Organizations have also been changed by the Internet it enables different management styles, decentralization, rapid innovation, easier collaboration between companies, and so forth.

The Internet has also changed society. For example, its facilitated the move toward globalization, improved national economies, and affected politics, schools and health care.

To give just one example, President Obama made very good use of the Internet while campaigning.

As Kennedy was the first television President, Obama may be thought of as the first Internet president both while campaigning and while in office.27Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (text)User skillsTwitterBloggerGoogle docsGoogle spreadsheetWikispaces wikiZoho creator databaseCollaborationSurvey gizmoListserverSubscription (RSS and email)HTMLPublish Web pages using FTP

Application development platformsWe used each of these Internet platforms during the term.

They are personally and professionally useful tools.28A two column interfacePost title and dateFooterPost bodyAdditionalinformationInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills29This wire frame diagram shows the basic structure of the user interface of our class blog.

The body of the post is on the left, additional information is in the column on the right and there is a header and footer.

We use wire-frame diagrams in designing Web pages.

The screen real estate is limited, so one must plan carefully.

You can also use a wire-frame diagram when learning a new program.

After working with it for a little while, try drawing up its wire frame diagram showing how each portion of the screen is used.

Batch processing and time sharingPersonal computerInternet platformApplication developmentInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (text)User skills30In the early days of computing when we used batch processing and time sharing on giant sized computers -- only skilled professionals could develop new applications. You really had to be kind of a nerd.

The advent of the personal computer and spreadsheet made developing applications much easier.

Business people and others began building spreadsheets, databases, reporting systems, slide presentations and more without the help of a professional programmer.

Today, Internet era tools have lowered the bar even further.

Those spreadsheets, databases and presentations are even easier to build and share online and you can create applications using tools like blogs and wikis in just a few minutes.

Content creation data typesVideoImageTextAudioInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (text)User skills31This slide shows four data types, and we need to be able to work to some extent with each of them.

You are already familiar with the mechanics of word processing, but Internet writing is somewhat unique, so well focus on writing style and technique rather, not the mechanics of using the software.

Todays student also needs to be able to capture and edit image, video and audio data, so well spend some time on those skills as well.

We did not have time for hands on video, but the editing paradigm is like that of audio.

You place video clips on a timeline and perform editing operations like cut, paste, move and copy.

When you finish editing, you compress then distribute the video.Data typesData typeDecadeNumeric1950sAlphanumeric1960sText1970sImage1990sSpeech2000sMusic2000sVideo2000, 2010sInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills32As technology improves, we can afford to work with more complex types of data.

Early computers were focused on numeric data, and today high quality video is becoming economically feasible.

Mainstream products are preceded by research and development of prototypes, which often takes many years.

Tomorrows products are in the lab today.

010101011100101010101010101010111010101010101010101010101010100101010101000010110101010101010010101101101010101010110010110010101010100101110101001010010101010101010001001010101011010011010010101010100101101001011100101010101001010101000101010101010101010010101001010101001001001001010101001000101010101110100101001010101010010101010101001010100100101010010101001001010101001010100101010100101010101001010101011110101011100001111011All data is binaryInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsWe store text, image, video, and audio data as well as programs to execute.

Regardless of the data type, theyre all are stored as bits, as 1s and 0s.33PrefixMeans Exact valuekilo1024^11,024mega1024^21,048,576giga1024^31,073,741,824tera1024^41,099,511,627,776PrefixMeans Close enough Decimal namekilo1000^11,000thousandmega1000^21,000,000milliongiga1000^31,000,000,000billiontera1000^41,000,000,000,000trillionNumeric prefixes exact and close enoughInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skillsA bit is a single one or zero.

What about a kilobit?

The exact meaning of a kilobit is 1,024 bits.

But its close enough for most discussions to approximate that as 1,000 bits.

Similarly, a megabit is approximately a million bits.

A gigabit is approximately a billion bits.

A terabit is approximately a trillion bits.

After these prefixes come peta, exa, zetta, yotta and more.

The pattern continues -- each is 1,024 times the previous one.34L01001100a01100001r01110010r01110010y01111001Larry0100110001100001011100100111001001111001Data + a code informationInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills35Using our character code, we can now decipher the 40 bits of data.

As you see, data plus a code yields information.

This slide uses text as an example, but images, video, audio all information consists of encoded data.More bits means more unique codesA 00B 01C 10D 11A 0B 1A 000B 001C 010D 011E 100F 101G 110H 111A 0000B 0001C 0010D 0011E 0100F 0101G 0110H 0111I 1000J 1001K 1010L 1011M 1100N 1101O 1110P 1111

1-bit code 2-bit code 3-bit code 4-bit code36Lets say you wanted to invent a code for text data.

If you had a one-bit code, you could only have two letters A and B.

That is surely too few. What if we add a second bit?

A two-bit code gives four unique combinations, so we could have four letters in our alphabet.

As you see here, a three bit code gives us 8 letters and a four bit code 16.

The more bits in our code, the more combinations are possible.

More unique codes means more information.

All data types are compressibleImageTextNumericAudioVideo

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills37All types of data can be compressed.

With numbers and text, a compressed file must be identical to the original we require lossless compression.

In most applications, we can afford some loss, some deterioration of quality when compressing image, video or audio data.

The tradeoff is that as file size increases, quality improves and vice versa.

Internet writing is importantProbably the most important thing and probably one of the surprises is you have to work with people who are good writers.When hiring, Jason Fried looks for:A positive attitudeA well rounded, flexible personA quick learnerTrustworthiness an independent workerA good writer

Writing (34 sec)All five criteria (2m 42sec)

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (text)User skills38Jason Fried is the founder of 37 Signals, a prominent Internet software company.

Fried speaks and writes frequently on software design and development.

In one talk, he outlined the five things he looks for when interviewing job applicants.

As you see, he considers being a good writer the most important.

Stop at this point and listen to these two short excerpts from Frieds talk.

The short excerpt focuses on writing.

In the longer one, he explains each of his five hiring criteria.Collaborative writingConversational writingWriting short documentsThree tipsInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (text)User skillsWe saw separate presentations on all three types of Internet writing, and each will contain tips and suggestions.

If you skip those three presentations, let me leave you with one critical tip for each,

When you write a short document, your first draft sucks. If at all possible, leave time for revising it after it has been set aside for a while. Better yet, ask someone else to read it for you and give you feedback.

For conversational writing, carefully reading what the other person said before replying is critical. If you read carefully there will be no loose ends at the end of the conversation. We all tend to skim and read superficially on the Internet. Superficial reading leads to ineffective conversations.

Finally, for collaborative writing it is not sufficient to have a shared document to work on. You and your colleagues need a second communication channel for organizing the team and the emerging document, The second means of communication can be using an Internet tool like chat or a discussion page or face-to-face meetings, but it must be provided for.39Image processing work flowCapture

Edit

Compress

DistributeInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (image)User skillsThis is your image processing work flow.

You begin by capturing an image perhaps from a camera, a scanner or by copying it from the Web.

Capture as high a quality original image as you can set your camera to high quality or use a high-resolution scanner.

In other words, capture as much information as you can.

Next you use your image processing program to modify the image to suit your application -- perhaps touching it up, cropping and resizing it, changing the contrast and so forth.

The next step is compression making the file as small as you can while maintaining the image quality your application requires.

After you compress it, your file is ready to distribute.40Image characteristics

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (image)User skillsWe covered six image characteristics size, shape, resolution, amount of information, file type and whether it is flat or photographic.

To do so, we had to introduce the idea of pixels, and we also discussed image compression.4112 colors, 12 codes

ColorCodeBlue0000Light green0001Dark green0010Yellow0011Orange0100Red0101Purple0110Light grey0111Dark grey1000Brown1001Black1010White1011Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (image)User skills42Here we see a code for our picture.

Each pixel is one of 12 colors and each color has a four bit code.

96% reduction

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (image)User skillsThis compressed image is down to 3.8 kilobytes, a 96% reduction in file size.

The pixilation is obvious.

We have thrown away most of the information in the picture.

Note that the size of the image has remained the same 359 by 381 pixels.

The information loss was due to a reduction in the color palette -- the number of colors a given pixel could be.

No variety means no information.43

RGBInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (image)User skillsWeve seen that varying the intensity of red, green and blue light determines the color of a pixel.

We also saw that one can write a number in decimal, hexadecimal or any other counting system.

You can specify an exact color in HTML by writing its red, green and blue intensity values in hexadecimal.

44

Analog to digital converterDigital to analog converterRecording and playing soundComputer10010110 (150)11001001 (201)11000111 (199)Computer10010110 (150)11001001 (201)11000111 (199)

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (audio)User skills45A microphone converts the sound it picks up into a continuously varying voltage.

That signal is fed to an analog to digital converter, a chip that encodes it as a series of numbers.

Playback reverses the process,

The computer outputs the numbers to a digital to analog converter which converts them to a continuously varying signal that drives a speaker.

http://som.csudh.edu/fac/lpress/presentations/clocks/clocks.html

Which clock is digital? Analog?Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (audio)User skills46The signal coming from a microphone is continuously varying analog data.

But, analog data must be converted to digital data if it is to be processed by a computer.

Sampling an analog signal

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (audio)User skills47We convert analog data to digital by sampling the incoming signal at a fixed rate.

The more samples we take per unit of time, the better the digital data will approximate the analog signal.

Each sample is a number, and the larger the number can be (the number of bits in the number) the better the approximation will be.Increase sample rate quality file size Increase sample size quality file size Recording tradeoffsInternet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (audio)User skills48Increasing the sample rate will improve the sound quality, but it increases the size of the sound file.

If, for example, we take 10,000 samples per second, we end up with 10,000 numbers for each second of recorded sound.

If we double the sample rate to 20,000 samples per second, we double the number of numbers which have to be stored.

Similarly, if we increase the number of bits in each sample, we improve sound quality, but the sound file will be larger.

This holds true for any analog data, not just sound coming in from a microphone.User skills

Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creation (audio)User skillsWe did not spend a lot of time on user skills since you are already familiar with applications like search and word processing.

That also made it easy to pick up on using something like a networked word processor.

We did review domain names and the way the domain name system works.49The parts of a domain nameThe particular host is called somThe organization that owns the name it is csudhThis host is at an educational organizationsom.csudh.eduInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skills50You are familiar with domain names.

For example, you often type them into Web browsers as part of a URL.

A domain name like som.csudh.edu identifies a particular host that is connected to the Internet.

As shown here, each part of the domain name has a meaning lets look closer.The system is hierarchicalInternet conceptsApplicationsTechnology (communication)ImplicationsInternet skillsApplication developmentContent creationUser skillsDomain names are organized hierarchically and so is the responsibility for maintaining the database that matches IP addresses with names.

If, for example, you want to get a name in the .com domain, you apply to a registrar who checks to see if it is available, and if it is, assigns it to you (for a fee).

There are many commercial registrars for some domains like .com.

One organization, a professional society, controls .edu.

The University of Chile Computer Science Department controls .cl., etc.

At CSUDH, our network administrator assigns the names and enters them into our domain name database.51The invention of hypertext

Vannevar BushArtists conception of a memexSome people we mentioned.52The idea of a network with hypertext documents preceded the Web or the Internet.

Perhaps the first to imagine a network of linked documents was Vannevar Bush, an MIT professor and science advisor to President Roosevelt during World War II.

He published an article entitled As We May Think in the Atlantic Monthly and it was reprinted in Life Magazine.

In the article, Bush described a hypothetical machine he called a memex.

He predicted that future scientists would work at memex desks connected by a network.

He saw them publishing research results and linking their papers to those of others.

The entire scientific community would be online and their publications linked.

Bushs speculation about the technology that would be used was wrong, but the vision was prophetic.Doug Engelbart

Some people we mentioned.53Doug Engelbart read Bushs article and, after being discharged from the Navy, decided to devote his career to implementing Bushs vision to using computers to augment human intellect.

During the 1960s, Engelbart and his colleagues at the Stanford Research Institute built prototypes of many of the tools we use today , including linked documents.

(The term hypertext was coined later by Ted Nelson).

On the right, we see a photo of Engelbart during a famous 1968 demonstration at a computer science conference.

In that presentation, Engelbart unveiled inventions like the mouse, a user interface with windows, word processing in which documents were formatted on the screen as they would print, shared databases, synchronous and asynchronous collaboration, and more.

Known simply as The Demo, it inspired the work of the inventors of the personal computer and the inventors of the Internet.

Tim Berners-Lee invented the Web

Some people we mentioned.54Gopher was quite popular in the early days of the Internet, but it was quickly displaced when the World Wide Web was invented.

Here we see a screen shot from the first Web client, a picture of its author Tim Berners Lee, and the first image ever posted on the Web.

The Web was similar to Gopher, but had several additional features.

For example, Web pages could include pictures and could have links to other pages.

Berners-Lee worked at CERN, a Swiss physics research facility, and he wrote his Web client and Web server software so physicists around the world could share and link to research reports.Ping and traceroute

Two programs, ping and traceroute, help us make IP, the Internet layer protocol, concrete.

Ping reports the amount of time it takes a packet to go from one host to another and back.

The client sends a data packet to a remote host.

When the packet arrives, the remote host sends back and acknowledgement.

When that arrives, the client records and displays the round trip time.

Traceroute is not concerned with the time the packet takes to traverse the network, but the route it takes.

Packets hop from one router to the next, moving closer to their destination with each step.

Traceroute lists the IP addresses and, if available, domain names of the intermediate routers.

Lets look at some ping times.55

C:\Users\Larry>ping www.puc.cl

Pinging www.puc.cl [146.155.99.60] with 32 bytes of data:Reply from 146.155.99.60: bytes=32 time=182ms TTL=110Reply from 146.155.99.60: bytes=32 time=180ms TTL=110Reply from 146.155.99.60: bytes=32 time=177ms TTL=110Reply from 146.155.99.60: bytes=32 time=185ms TTL=110

Ping statistics for 146.155.99.60: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 180ms, Maximum = 185ms, Average = 181ms

C:\Users\Larry>Ping Catholic University, Santiago ChileHere I pinged Catholic University in Santiago, Chile.

The round trip time averaged 181 milliseconds and the air distance is 5,600 miles.

That turns out to be around 62,000 miles per second about 1/3 the speed of light.

That is simply amazing!

But, what was involved in doing this how many routers did the data pass through?

To answer that, we run Traceroute.56

Two views of Bit TorrentWe cannot end a discussion of Bit Torrent without mentioning that it is controversial.

There are two views of Bit Torrent.

Record, television and movie producers see it as a tool for pirating their content, and, indeed many copyrighted works are available as torrents.

Others see it as a way to efficiently distribute large files to many locations, because there is no central server to act as an upload bottleneck.

Like many tools, Bit Torrent can be used for good and bad.57

And we cannot discuss copyright without mentioning Creative Commons licenses.

It turns out that any original work you create is copyrighted by default.

If you want to enable others to share and work with your content, you must license it to them.

There are several options in a Creative Commons license.

For example, the presentation you are viewing has a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

That means anyone can use the material for any non-commercial application as long as they credit the source and apply the same license to their derived work.

Creative Commons licensing was invented by legal scholar Larry Lessig.

There are links to many of his works on the Resources slide of this presentation, and I recommend watching his presentation on copyright.

58

The height attribute of the img tag

Another attribute of the img tag is height.

Here we have assigned it a value of 200.

As you see, the image is distorted, because the width was not automatically adjusted to compensate for the reduced height the aspect ratio of the image has changed.

Using the height and width attributes is dangerous you are better off resizing your images before including them in a Web page.59

Connectivity from three types of locationHomeMobileOrganization60We connect to the Internet from our homes and organizations and when moving around.

There are different connectivity considerations and options for each case.

LANHome or organization

MobileInternet service providers61Users connect through Internet service providers or ISPs.

Mobile users connect directly to their ISP.

A home or organization that has more than one computer, will build a local area network (LAN).

Home and organization users connect to their LANs, and the LAN connects to the ISP.

Note that we can distinguish between mobile and portable connectivity.

A user with a mobile phone or tablet would connect directly when outside and connect through a LAN when in a home or office.

Lets consider both cases, starting with the mobile user.ABC pricesHTML for this exampleThe link textThe link destination62The tag is used to create a link.

That may sound like a strange name to use why not call it the tag link for example?

Tim Berners Lee, who invented HTML and the Web protocol, was thinking that this was the anchor point for the link.

The href attribute of the a tag specifies the link destination -- http://www.abc.com/prices.htm in this example.

That says we want to go to the page called prices.htm on the Web server with the domain name www.abc.com.

The link text is between the end of the tag and the which ends the link.ITmajorsOthermajorsOther majorsToday, everyone is a creator and a manipulator of information.

Students in every field art, music, literature, journalism, the sciences, and so forth all require somewhat different IT literacy foundations.

63...Topic modulesComplete courseSupplementMy solution is a set of modules.

A complete course can be assembled from a subset of those modules.

Or an existing course can be augmented with smaller subset/

For example, and English class might use a few modules on writing for the Internet and a journalism class a few modules on audio recording and editing.64

Summary

Weve presented two researchable questions should images be labeled and by how much can we increase presentation tempo without cutting comprehension and retention. 65More pixels more informationMore color variety more informationWe can add a second statement on the amount of information in an image.

Adding color variety adds information.

We allow for more unique colors in an image by increasing the number of bits for each pixel.

The more bits per pixel, the more possible colors.

The relationship between image size and information is perhaps more intuitive than the one on color variety.

Let me give you one more illustration of the importance of color variety.

66Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam quis nibh quis dolor molestie mollis. Sed quis risus a lacus vestibulum molestie. Donec velit ante, feugiat sit amet dictum sed, ullamcorper vitae mi. Cras odio libero, malesuada ac bibendum non, pellentesque vitae elit. Aenean sed mi sed lorem malesuada faucibus eget sit amet neque.

In hac habitasse platea dictumst. Ut id blandit massa. Pellentesque consectetur tristique ultrices. Donec vitae nisl quam, et varius mauris. Vivamus mollis, arcu eget sagittis pharetra, odio felis vestibulum lacus, in hendrerit orci lacus vitae ligula. Fusce ullamcorperLoremAugue viverra mollisQuisque tristiquedapibus dui, sed mollisTurpisTempusMauris laciniaUltricies maurisvarius nibh lobortis etEuismodCondimentum id id estSed sit amet ligula vitae est pulvinarSuspendisse at nisiNullam lobortis arcuA magna consequatSuspendisse ornareAnte id erat temporDont do thisPeople make jokes about boring PowerPoint presentations.

But that is because presenters make common mistakes.

They rely too much on bullet points to present overly complex outlines.

They use too much text, which distracts the audience because they read it instead of listening to the presentation.

(It is even difficult to stop reading Latin nonsense).

They try to cram too much onto overly complex slides.

Dont make these mistakes.

Contrast this with the style of Steve Jobs of Apple, a master of the simple slide.

Lets look at a few examples.

67

Interactive videoAudio sound trackPowerPoint slidesContinuous videoCreate the videoAt this point I have copies of each slide, saved as a .png image, and the sound track saved as a .wav file.

I use a video editing program called Camtasia Studio to combine them, creating a narrated video of the presentation.

I make two versions of the video one is a normal, continuous video that can be uploaded to Youtube or any other video site.

The other is a small Web page that appends a table of contents to the video, enabling the viewer to jump from slide to slide.

That Web page can be uploaded to any Web server.

If Audacity and Camtasia Studio are new to you, youll have to spend time playing around with them.

Each has many options, and each uses the same basic timeline user interface.68

While editingText editors were invented before word processors, and you might think of them as bare-bones word processors.

Here we see screen shots of Microsoft Word, a word processor, and Microsoft Notepad, a text editor.

Both are used to create text documents, but Word is able to represent more than plain text.

The Word document can represent text color, size, font and so forth., while the Notepad document is plain text nothing but letters of the alphabet.

The Word document encodes more than just the text characters.69We don't plan to continue developing Wave as a standalone product, but we will maintain the site, at least through the end of the year.

Senior Vice President Urs Holzle8/04/2010 02:00:00 PM

Zap!!Google Wave is discontinuedA vendor might go broke or decide to discontinue a service.

Google was disappointed with the number of users who signed up for a collaboration application called Wave and discontinued it with this announcement.

70$ $ $Contract terms can changeEven if a vendor continues to support a service, they can change the fee structure and other business terms.

You need a contract that spells out the business side of the deal.71http://twitter.com/share?_=1298645244098&count=horizontal&original_referer=http://globalvoicesonline.org/2011/02/21/cuba-generacion-y-and-voces-cubanas-unblocked-in-cuba/&related=ellerybiddle:Post%20author&text=Cuba:%20Generaci%C3%B3n%20Y%20and%20Voces%20Cubanas%20Unblocked%20in%20Cuba&url=http://globalvoicesonline.org/2011/02/21/cuba-generacion-y-and-voces-cubanas-unblocked-in-cuba/&via=globalvoices

How they did it -- the APIHow did Twitter know the name of the blog, its URL and the title of the post?

When I clicked on the Tweet button, the information was appended to the URL and sent back to Twitter.

The rules specifying the format of that information constitute the API.

Twitter has defined an interface for applications that use its programs and data.

Someone at Global Voices had to understand the API and write a tiny chunk of code, but it is quite simple.

I bet you can figure out most of the API format by reading the call shown above.

How did Twitter know who I was, who should send out the tweet?

They got my login information from a small record called a cookie stored on my laptop.

72

If you run your own servers, your capacity steps each time you add servers.

Just after you add some servers, you are over capacity.

If you wait too long to add servers, response time will be slow and your customers unhappy.

Cloud services like Amazon solve this problem capacity grows smoothly as usage increases.73Development tools

Amazon now has competitors in the infrastructure services market and equipment and communication costs are constantly dropping.

That says the cost of starting and then operating a new Internet service will go even lower.

And there is more good news.

Amazon and their competitors work constantly on new developer tools, making it ever easier to develop new services.

You no longer need a venture capitalist to start a new Internet service just an idea, a credit card and a few spare months.74

The Twitter ecosystemMany companies have services that supplement Twitter.

They make Twitter more useful and valuable.

They form its ecosystem.

Lets look at one of them Twitpic, which you can use to post a tweet with a link to an image or short video.75Who are you?IP address + time and date + ISP log

Internet account holder76If I know your IP address, the time and date you were on line and have access to the logs maintained by your internet service provider, I can identify you.

As we have seen, the client IP address, time and date you were on line and the identity of your Internet service provider (ISP) can be captured by a server.

But, what about the logs the ISP keeps?Internet access

How do you access the Internet?Many people access the Internet from more than one place and one computer.

Data and programs that are stored online are accessible from everywhere.

You can also get away with a less capable client device in some cases.77Number of edits over time

This graph shows that there have been over 1,600 edits since the page was created.

The red line shows the number of edits per month.

As you see, activity spiked in 2004 then dropped off.

The green line shows the number of unique addresses from which edits were made.

The number of edits is greater than the number of editors in any month, indicating that there are conversations among those making the changes.

This was particularly notable when edits spiked.

Minor edits are shown in ochre.78

Grow by the same amount in each time periodGrow by the same percent in each time periodLinear versus exponential growth79You may have heard the term exponential growth.

People often use it as a synonym for rapid growth, but it has a more precise definition.

It means is that something is growing at a constant rate rather than by a constant amount.

That sounds like a small difference, but look at an example.

The first CPU chips had about 2,300 transistors.

If that had gone up by a constant amount, say 2,000 transistors a year we would be up to about 80,000 transistors on a chip.

Instead, we are up to over 2 billion, because the number of transistors grew by about 50% per year. Increase sample rate quality file size Increase sample size quality file size Recording tradeoffs80Increasing the sample rate will improve the sound quality, but it increases the size of the sound file.

If, for example, we take 10,000 samples per second, we end up with 10,000 numbers for each second of recorded sound.

If we double the sample rate to 20,000 samples per second, we double the number of numbers which have to be stored.

Similarly, if we increase the number of bits in each sample, we improve sound quality, but the sound file will be larger.A digital clock000201030401.4981The clock on the left is digital because it jumps from second to second, while the right hand clock runs smoothly between seconds

Digital data is discreet and jumpy, not smooth and continuous.

The digital clock cannot show the time between seconds, so it must round off to the nearest second.

It will read 01 until the half-way point between 01 and 02, then jump abruptly to 02.

Now, lets look at analog sound recording.

As we will see, rounding off reduces audio recording accuracy.

AnalogDigitalWeve used sound as an example, but, in general, real world phenomena like sound, time, distance, speed, acceleration, temperature, and pressure are analog.

Todays computers are digital devices.

Since computers work on digital data, sensor data must be sampled and digitized before it can be processed.82