Technology Saturday

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Technology Saturday

• Everything you wanted to know about computer
  technology, but didnt know what to ask.

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Web Conferencing

• Web conferencing is used to conduct live meetings
  or presentations via the Internet. In a web
  conference, each participant sits at his or her
  own computer and is connected to other
  participants via the internet. This can be either
  a downloaded application on each of the attendees
  computers or a web-based application where the
  attendees will simply enter a URL (website
  address) to enter the conference.

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Web Conferencing - Webinar

• A webinar is a neologism to describe a specific
  type of web conference. It is typically one-way,
  from the speaker to the audience with limited
  audience interaction, such as in a webcast. A
  webinar can be collaborative and include polling
  and question answer sessions to allow full
  participation between the audience and the
  presenter. In some cases, the presenter may speak
  over a standard telephone line, pointing out
  information being presented on screen and the
  audience can respond over their own telephones,
  preferably a speaker phone. There are web
  conferencing technologies on the market that have
  incorporated the use of VoIP audio technology, to
  allow for a truly web-based communication.
  Webinars may (depending upon the provider)
  provide hidden or anonymous participant
  functionality, enabling participants to be
  unaware of other participants in the same
  meeting.

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Web Conferencing Web Meeting

• A web meeting differs from a webinar in that
  there is opportunity for participant interaction.
  
• GoToMeeting is a Web conferencing tool that
  allows you to meet online rather than in a
  conference room. Its an easy and cost-effective
  way to organize and attend online meetings. The
  technology enables participants to view any
  application running on a PC in real time.
• Watch Demo

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Podcast

• iPod broadcast, ornow Personal On Demand
  broadCASTING
• A podcast is a series of audio or video
  digital-media files which is distributed over the
  Internet by syndicated download, through Web
  feeds, to portable media players and personal
  computers. Though the same content may also be
  made available by direct download or streaming, a
  podcast is distinguished from other digital-media
  formats by its ability to be syndicated,
  subscribed to, and downloaded automatically when
  new content is added. The host or author of a
  podcast is often called a podcaster.

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RSS - Web Feeds

• RSS Really Simple Syndication
• A web feed (or news feed or rss feed or
  syndicated feed) is a data format used for
  providing users with frequently updated content.
  Content distributors syndicate a web feed,
  thereby allowing users to subscribe to it. Making
  a collection of web feeds accessible in one spot
  is known as aggregation, which is performed by an
  Internet aggregator.
• In the typical scenario of using web feeds, a
  content provider publishes a feed link on their
  site which end users can register with an
  aggregator program (also called a feed reader or
  a news reader) running on their own machines
  doing this is usually as simple as dragging the
  link from the web browser to the aggregator. Web
  feeds are operated by many news websites,
  weblogs, schools, and podcasters.

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RSS - Feed Reader

• Benefits
• Web feeds have some advantages compared to
  receiving content via email
• When subscribing to a feed, users do not disclose
  their email address, so users are not increasing
  their exposure to threats associated with email
  spam, viruses, phishing, and identity theft.
• If users want to stop receiving news, they do not
  have to send an "unsubscribe" request users can
  simply remove the feed from their aggregator.
• The feed items are automatically "sorted" in the
  sense that each feed URL has its own sets of
  entries (unlike an email box, where all mails are
  in one big pile and email programs have to resort
  to complicated rules and pattern matching).
• A "Feed Reader" is required for using Web Feeds.
  This tool works like an automated e-mail program,
  but no e-mail address is needed. The user
  subscribes to a particular web feed, and
  thereafter receives updated content. Feed readers
  are used in personalized home page services like
  iGoogle or My Yahoo or My MSN to put content such
  as news, weather and stock quotes appear on the
  users personal page.
• Many mobile devices can act as feed readers.

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Streaming Video and other Media

• Streaming media is multimedia that is constantly
  received by, and normally presented to, an
  end-user while it is being delivered by a
  streaming provider (the term "presented" is used
  in this article in a general sense that includes
  audio or video playback). The name refers to the
  delivery method of the medium rather than to the
  medium itself. The distinction is usually applied
  to media that are distributed over
  telecommunications networks, as most other
  delivery systems are either inherently streaming
  (e.g. radio, television) or inherently
  non-streaming (e.g. books, video cassettes, audio
  CDs). The verb 'to stream' is also derived from
  this term, meaning to deliver media in this
  manner.

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Flash

• Adobe Flash (previously called "Macromedia
  Flash"') is a multimedia platform created by
  Macromedia and currently developed and
  distributed by Adobe Systems. Since its
  introduction in 1996, Flash has become a popular
  method for adding animation and interactivity to
  web pages Flash is commonly used to create
  animation, advertisements, and various web page
  components, to integrate video into web pages,
  and more recently, to develop rich Internet
  applications.
• Flash can manipulate vector and raster graphics
  and supports bi-directional streaming of audio
  and video.
• YouTube uses Flash to deliver videos on the web.

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Streaming MP3

• MP3 is a digital audio encoding format using a
  form of lossy data compression. It is a common
  audio format for consumer audio storage, as well
  as a de facto standard encoding for the transfer
  and playback of music on digital audio players.
  MP3 is an audio-specific format that was designed
  by the Moving Picture Experts Group.Just as
  music can be streamed over radio waves. Music can
  also be streamed over an IP network.
• Kens music server http//kenz.homeip.net9000Ke
  ns MP3 stream http//kenz.homeip.net9000/stream
  .mp3

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Downloading and Uploading Files

• DownloadTo download is to receive data to a
  local system from a remote system, such as a
  webserver, FTP server, mail server, or other
  similar systems. A download is any file that is
  offered for downloading or that has been
  downloaded. The word's primary usage comes in the
  form of a verb. Websites that offer streaming
  media such as YouTube, place restrictions on the
  ability of users to save these materials to their
  computers after they have been received, say that
  downloading is not permitted. In this context,
  "download" implies specifically "receive and
  save" instead of simply "receive."
• UploadThe inverse operation, referred to as
  uploading, is to send data from a local system to
  a remote system, FTP server, website, etc., with
  the intent that the remote system should save a
  copy of whatever is being transferred. For
  example, "Uploading a video to Wikipedia" means
  to transfer a copy of a video file from your
  computer to this website, such that both systems
  retain identical copies.
• SideloadWhen applied to local transfers, it is
  often difficult to decide if it is an upload or
  download. While there is a technically correct
  answer, most non technical users tend to use the
  term download to refer to any data transfer. The
  term "sideload" is increasingly being used to
  cover all local to local transfers to end this
  confusion.

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Computer Files

• A computer file is a block of arbitrary
  information, or resource for storing information,
  which is available to a computer program and is
  usually based on some kind of durable storage. A
  file is durable in the sense that it remains
  available for programs to use after the current
  program has finished. Computer files can be
  considered as the modern counterpart of paper
  documents which traditionally were kept in
  offices' and libraries' file cabinets, which are
  the source of the term.

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File Contents

• At the lowest level, many modern operating
  systems consider files simply as a
  one-dimensional sequence of bytes. At a higher
  level, where the content of the file is being
  considered, these binary digits may represent
  integer values, text characters, image pixels or
  anything else. It is up to the program using the
  file to understand the meaning and internal
  layout of information in the file and present it
  to a user as more meaningful information (like
  text, images, sounds, or executable application
  programs).

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File Size

• At any instant in time, a file might have a size,
  normally expressed as number of bytes, that
  indicates how much storage is associated with the
  file. In most modern operating systems the size
  can be any non-negative whole number of bytes up
  to a system limit. However, the general
  definition of a file does not require that its
  instant size has any real meaning, unless the
  data within the file happens to correspond to
  data within a pool of persistent storage.

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Some Typical File Size Names

• Bit one binary digit, either 1 or 0. The only
  logical value it can have is true/false, on/off,
  yes/no, etc.
• Byte (b) a group of eight bits that can
  represent the numbers 0-255 (28) or -127 to 128
  (27 with 1 bit for the sign).
• Word machine dependant 32 bit computer has a
  4 byte word.

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Some Typical File Size Names

• Kilobyte (kb) 1024 bytes (a metric value) -
  often referred to as 1000 bytes (an SI decimal
  value)
• Megabyte (Mb) 10242 bytes 1 Million
• Gigabyte (Gb) 10243 bytes 1 Billion
• Terabyte (Tb) 10244 bytes 1 Trillion

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Representing Characters with Bytes

• If a byte can only store numbers, then how does a
  computer store a character such as the letter
  A?
• American Standard Code for Information
  Interchange (ASCII), is a character-encoding
  scheme based on the English alphabet. ASCII codes
  represent text in computers, communications
  equipment, and other devices that work with text

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Representing Characters with Bytes

• The ASCII code for the letter A is 65. The code
  for a is 97. The code for 3 is 51.
• The ASCII code used one byte (for a maximum of
  256 characters ) to encode the English character
  set. While this was ingenious, it was also
  ethnocentric.
• A new standard (Unicode) that uses more bits has
  been devised so that non-English characters can
  be incorporated.

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Representing Pictures with Bytes

• PixelIn digital imaging, a pixel (picture
  element) is the smallest piece of information in
  an image. Pixels are normally arranged in a
  regular 2-dimensional grid, and are often
  represented using dots, squares, or rectangles.

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Representing Pictures with Bytes

• Pictures are represented as two-dimensional
  arrays of pixels. Think of your grandmothers
  needlepoint as an example of a 2-D array.

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Representing Color with Bytes

• Bits per pixel
• The number of distinct colors that can be
  represented by a pixel depends on the number of
  bits per pixel (bpp). A 1 bpp image uses 1-bit
  for each pixel, so each pixel can be either on or
  off. Each additional bit doubles the number of
  colors available, so a 2 bpp image can have 4
  colors, and a 3 bpp image can have 8 colors
• 1 bpp, 21 2 colors (monochrome)
• 2 bpp, 22 4 colors
• 3 bpp, 23 8 colors
• ...
• 8 bpp, 28 256 colors
• 16 bpp, 216 65,536 colors ("Highcolor" )
• 24 bpp, 224 16.7 million colors ("Truecolor")
• Color can be encoded in different ways, usually
  indexed, or the bits signify varying levels of
  Red, Green, and Blue (RGB) or levels of Cyan,
  Yellow, Magenta, and Black (CYMK)?

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Not All Pixels are the Same Size

• Dots per inch (DPI) (or Pixels per inch PPI) is a
  measure of spatial printing or video dot density,
  in particular the number of individual dots that
  can be placed within the span of one linear
  inch.
• Computer screen pixels are usually 72 or 96
  dpi.
• Printer pixels are smaller. Common sizes include
  300 dpi and 600 dpi.
• A 1000 x 1000 pixel (one megapixel) picture would
  measure about 14 x 14 on your screen.
• The same picture, when printed at 300 dpi would
  only measure about 3 inches square on a sheet of
  paper.

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Not All Picture File Formats are the Same

• Bitmap (bmp) Up to 4 bytes per pixel.8x10
  picture at 600 dpi and a 32 bit color depth
  would take(8x600) x (10x600) x 4 115,200,000
  bytes ( 115 Mb) of storage.
• That is the equivalent of 80 million floppy disks!

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Not All Picture File Formats are the Same

• JPEG (jpg) is a commonly used method of
  compression for photographic images. The degree
  of compression is adjustable, allowing a
  trade-off between storage size and image quality.
  JPEG typically achieves 101 compression with
  little perceptible loss in image quality.
• Our 115 Mb file is now 12 Mb

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Not All Picture File Formats are the Same

• JPEG uses lossy compression. This means data from
  the original bitmap is lost. Subsequent
  compression of the same file results in further
  data loss. High compression ratios also have high
  data loss.

JPEG with increasing levels of compression from
left to right.
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Not All Picture File Formats are the Same

• JPEG works best on photo type pictures. It does
  not work well on solid color graphics.

Original WNC.bmp was 117 Kb
JPEG File2.7 Kb Loss resulted inArtifacts
GIF File4.2 KbNo Loss
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Some Common Graphic File Formats

• Bitmap Raw data Full color - large files
• JPEG Lossy Compression small files Full
  range of colors Best for photos
• GIF Lossless compression small files
  Limited range of colors (indexed 256 color
  palette) allows simple animation - had some
  licensing issues.
• PNG (Portable Network Graphic) Improved GIF by
  adding full range of colors. Avoided license
  issue. (Patents are now expired, but license
  battle gave GIF a bad name.)?

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Not All Graphics Use Pixels

• Vector graphics is the use of geometrical
  primitives such as points, lines, curves, and
  shapes or polygon(s), which are all based upon
  mathematical equations, to represent images in
  computer graphics.
• Vector graphics formats are complementary to
  raster graphics (bitmaps), which is the
  representation of images as an array of pixels.

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File Compression

• The ZIP file format is a data compression and
  archive format. A ZIP file contains one or more
  files that have been compressed to reduce file
  size, or stored as-is. The ZIP file format
  permits a number of compression algorithms, but
  as of 2008, only Deflate is widely used and
  supported.
• ZIP is a lossless format.
• ZIP is often used as a container for multiple
  files.
• ZIP also supports the encryption of its
  contents.
• Support for ZIP files is built into Windows XP
  and Vista.

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Filenames and Filename extensions

• .bmp, .jpg, .gif, .ai
• .doc, .xls, .pdf, .ppt
• A filename extension is a suffix to the name of a
  computer file applied to indicate the encoding
  convention (file format) of its contents. In some
  operating systems (for example Unix and Apple
  Mac) it is optional, while in some others (such
  as Windows) it is a requirement. Some operating
  systems limit the length of the extension (such
  as DOS and OS/2, to three characters) while
  others (such as Unix) do not. Some operating
  systems (for example RISC OS) do not use file
  extensions.

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Files, Folders and Drives

• A computer file is a block of arbitrary
  information, or resource for storing information,
  which is available to a computer program and is
  usually based on some kind of durable storage.
• A folder is a logical grouping of zero or more
  files.
• A drive is the physical device that provides the
  durable storage.

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Files, Folders and Drives

• A computer file
• A folder is a logical grouping of zero or more
  files or other folders.
• A drive is the physical device that provides the
  durable storage.