Downloading and Storing Data

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Downloading and Storing Data
Tutorial 5

• Using FTP and Other Services to
• Transfer and Store Data

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Objectives

• Learn what FTP is and how it works.
• Explore how to use an FTP client program and Web
  browser to transfer files.
• Navigate an FTP site using a Web browser.
• Learn how to compress and decompress files and to
  check them for viruses.

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Objectives

• Download an FTP client program using a Web
  browser.
• Download a compression program using an FTP
  client program.
• Install and use a compression program.
• Trace the connection between your computer and a
  remote computer.

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Objectives

• Explore storage options on the Internet.
• Learn about emerging technologies for
  collaborative authoring on the Web.

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UnderstandingFile Transfer Protocol

• FTP (File Transfer Protocol) the Internet
  protocol that transfers files between computers
  that are connected to the Internet.
• FTP site (FTP server or remote computer) the
  site to which you are sending files and from
  which you are receiving files.
• Local computer your computer when you use it to
  connect to an FTP site.

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UnderstandingFile Transfer Protocol

• When you send a file using FTP, you upload the
  file to send it from your computer to the FTP
  site.
• When you receive a file, you download the file
  from the FTP site and receive it on your
  computer.
• FTP seamlessly transfers files between different
  operating systems.

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File Transfer Modes

• You can select one of two file transfer modes
• ASCII text contains symbols typed from the
  keyboard but does not include any nonprintable,
  binary codes
• binary files such as pictures, movies, sound
  files, and graphics
• Choose ASCII mode to transfer plain-text files.
• Choose binary mode for transferring everything
  else.

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File Types and Extensions

• The decision to transfer a file using binary or
  ASCII mode is largely determined by noting the
  files type. The file type can be determined by
  its extension.
• File extension the last three characters
  following the period in the filename.
• You can download files with a file extension of
  .txt in ASCII mode.
• You should download files with other file
  extensions (.doc, .xls, etc.) in binary mode.

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File Types and Extensions
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Connecting to an FTP Server

• To transfer files between your computer and a
  remote computer, you must first connect to the
  remote computer.
• You can connect to a remote computer by logging
  on to it using an FTP client program or your Web
  browser.
• Some FTP client programs and browsers will select
  the file transfer mode of binary or ASCII
  automatically.

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FTP Using an FTPClient Program

• FTP client program
• resides on your PC and transfers files between
  your computer and an FTP site
• most FTP client programs have menu bars or
  toolbars to help you execute commands
• FTP client programs transfer files quickly and
  provide features that let you resume downloading
  a file when your connection is lost or interrupted

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FTP Using an FTPClient Program
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FTP Using an FTPClient Program

• When selecting an FTP client program, choose one
  that supports all or most of the following
  desirable features
• Multipane display showing both the local remote
  computer directories.
• Allows you to transfer multiple files in one FTP
  session.
• Permits drag and drop file transfers.
• Simplifies the process of deleting directories on
  local and remote computers.

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FTP Using an FTPClient Program

• Desirable features (continued)
• Allows you to transfer selected files unattended.
• Recovers interrupted file transfers by continuing
  the transfer process from the point of
  interruption.
• Reconnects automatically to sites that disconnect
  a transfer when your connection exceeds the
  maximum allotted time.

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FTP Using a Web Browser

• Most Web browsers, including Internet Explorer
  and Firefox, support FTP, but have limited
  functionality when compared to FTP client
  programs.
• To upload a file, you must drag it from your
  desktop or Windows Explorer and drop it in the
  correct location in the browser window.
• To download a file, you select the file to
  download and tell the browser where to save it on
  your computer.

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FTP Using a Web Browser
FTP connection using Firefox
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Levels of Access for FTP Servers

• To use a remote computer, you must identify
  yourself, or log on, by supplying your user name
  and password.
• Public access anyone can connect to the FTP
  site. Access is restricted to only those files
  and folders designated for access by public
  users.
• Restricted access do not allow public visitors.

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Anonymous FTP

• Anonymous login logging on to one of the many
  publicly accessible, remote computers connected
  to the Internet.
• You use anonymous as your user name.
• Anonymous FTP session when you download or
  upload files using an anonymous login.

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Anonymous FTP
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Anonymous FTP

• Public FTP sites usually impose limits on
  uploading files or provide only one publicly
  accessible directory to which you can upload
  files.
• Access to selected files and directories is also
  limited.
• You should obey all rules and regulations
  regarding anonymous access.
• Look for the sites acceptable use rules and
  policies in the readme.txt file in the pub
  (public) directory.

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Full-Privilege FTP

• Full-privilege FTP FTP site access that
  requires a user name and password.
• The system might automatically direct you to a
  particular directory on the FTP site in which you
  have been given rights to upload and download
  files.
• You can usually store files for longer periods
  than you can on a public FTP site.

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Using a Public Directory

• Public directory (pub) the directory that some
  public FTP sites allow users with anonymous FTP
  access to view.
• Webmaster
• title given to the manager of a website
• must monitor the files uploaded to a public
  directory on a regular basis to check for viruses
  and to find and delete any illegally uploaded
  files

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Using a Web Browserto Navigate an FTP Site

• FTP sites are organized hierarchically, much like
  the folders and files on a computers hard drive.
• When you access an FTP site, you usually enter at
  the sites root directory.
• Most sites prevent users with anonymous logins
  from accessing some files and directories in the
  root directory.

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Using a Web Browser to Navigate an FTP Site
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Using a Web Browserto Navigate an FTP Site

• An FTP site usually stores directories (folders)
  and files.
• Double-clicking a file either opens the file in a
  new browser window or in a program window so you
  can view the file, or it begins downloading the
  file to your computer.
• Double-clicking a folder opens the folder and
  displays its contents.

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Using a Web Browserto Navigate an FTP Site
FTP site in Internet Explorer
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Using a Web Browserto Navigate an FTP Site
FTP site in Firefox
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Checking Files for Viruses

• Computer viruses are programs that infect your
  computer and cause harm to your disk or programs.
• Viruses pose a real and potentially costly threat
  to anyone using the Internet.
• You must know how to detect and eradicate viruses
  if you plan to download anything, including data,
  programs, or e-mail attachments.

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Checking Files for Viruses

• Virus detection software (antivirus software)
• regularly scans the files on your computer and
  files being downloaded to your computer
• files are compared to a signature that known
  viruses carry.
• virus signature (virus pattern or virus
  definition) a sequence (string) of characters
  that is always present in a particular virus
• When the virus detection program finds a virus
  signature, it warns you. You can either delete
  the file or ask the virus detection program to
  remove the virus.

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Checking Files for Viruses

• Two popular choices for protecting PCs are Norton
  AntiVirus and McAfee VirusScan.
• Antivirus software must be turned on, properly
  configured, and include current virus patterns to
  protect your computer from viruses.
• You must regularly download virus patterns from
  the server to keep your computer safe.
• One of the best ways to protect your computer
  from viruses is to be careful about which files
  you download and the sources you use to get those
  files.

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Checking Files for Viruses
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Visiting and Using aDownload Site

• A good way of locating software on the Internet
  is to use one or more Internet search engines.
• Several Web sites provide links to freeware and
  shareware programs. Some of these same sites
  also allow you to download programs directly.

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Downloading Programs

• Freeware software that is available to users at
  no cost and with no restrictions.
• Bugs errors sometimes contained in freeware due
  to limited testing of the software.
• Users must accept the implicit or explicit
  warning that the software might contain bugs.
• A lot of good-quality commercial software started
  as freeware.

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Downloading Programs

• Shareware
• similar to freeware, but it is usually available
  for free during a short evaluation period
• after the evaluation expires, it stops
  functioning
• users are expected to stop using it after the
  specified initial trial period and uninstall it
  from their computers
• anyone who likes the program and wants to
  continue using it can purchase a license
• usually more reliable than freeware because the
  shareware developer is sometimes willing to
  accept responsibility for the programs operation

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Downloading Programs

• Limited Edition (LE) or Evaluation Version
• a restricted version of a shareware program
• provides most of the functionality of the full
  version that is for sale
• omits one or more useful features of the full
  version
• you can sometimes download a limited edition
  version and use it for free

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Using a Web Browser to Download an FTP Client
Program

• Open the FTP site from which you will download
  the program.
• Navigate the FTP site to find the programs
  executable file, and then double-click the file
  (Internet Explorer) or click the file (Firefox).
• In Internet Explorer, click the Save button, use
  the Save in list arrow to navigate to the drive
  or folder in which to store the file, and then
  click the Save button. If necessary, click the
  Close button to close the dialog box.
• In Firefox, click the Save it to disk option
  button (if necessary), click the OK button, use
  the Save in list arrow to navigate to the drive
  or folder in which to store the file, and then
  click the Save button. If necessary, click the
  Close button to close the dialog box.

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Using a Web Browser to Download an FTP Client
Program

• The time it takes to transfer the program files
  varies based on the speed of your Internet
  connection and the amount of traffic at the FTP
  site.
• If you encounter problems while downloading a
  file, stop the process by clicking the Cancel
  button and try again later.
• After downloading anything from the Internet,
  your first priority is to scan the file for
  viruses.
• After installing any program, you can delete the
  downloaded files from the drive and folder to
  which you downloaded it, or you can keep it in
  case you need to reinstall the program.

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Using an FTP Client to Download WinZip

• File compression programs compress files to
  decrease the amount of space they require and
  also to decrease the time it takes to upload and
  download files.
• WinZip is a popular file compression program
  which is available for free during its evaluation
  period.
• When you use an FTP client program to save a
  sites address and your user name and password,
  you are creating an FTP session profile.

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Using an FTP Client to Download WinZip

• Log on to the remote computer by supplying its
  URL, your user name or anonymous, and your
  password.
• Navigate to the file you want to download.
• Click the filename on the remote computer to
  select it.
• If necessary, select binary or ASCII transmission
  mode.
• Execute the command that downloads the file from
  the FTP site to your computer and end the FTP
  session by disconnecting from the remote computer.

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Compressing andDecompressing Files

• Compressed files use less space when stored and
  they take less time to be transferred from one
  computer to another.
• File compression program decreases the original
  size of most files.
• After you download a compressed file, you must
  use a program to restore the file to its original
  state before you can open or execute it.
• The process of restoring a compressed file to its
  original state is called file decompression or
  file expansion.

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Compressing andDecompressing Files

• FTP recognizes most compressed files by their
  extensions.
• The most common extension for compressed files is
  .zip, which is why some people refer to
  compressed files as zip files or a zip archive.
• If you download a compressed file, you must have
  a file compression program installed on your
  computer to view its contents.

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Compressing andDecompressing Files
WinZip Add dialog box
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Compressing andDecompressing Files
Extract dialog box in WinZip
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Tracing an Internet Route

• Mirror site a replica of an existing server that
  provides an alternate location for downloading
  files.
• The distance between your PC and a remote
  computer on the Internet is measured in hops.
• Hop a connection between two connections.
• You can count the hops and identify the computers
  between your PC and a remote computer using the
  Windows tracert (for trace route) program.

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Tracing an Internet Route

• You can use the tracert program to make an
  informed choice when selecting a download site.
• Tracert will show you up to 30 hops and indicate
  the response time, the site name, and the IP
  address of each hop along the route.
• Ping (Packet Internet Groper) a program that
  tests a computer to determine if it is connected
  to the Internet.

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Tracing an Internet Route
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Using Online Storage Services

• When you use an ISP for your Internet connection
  and e-mail services, you might also receive some
  free space to use to store a Web site or files.
• Many services have evolved to meet the increased
  need for ways to store and share files. FTP
  sites are one way of sharing and storing files.
• ISPs and other entities have started providing
  three or more megabytes of storage space on their
  servers, either free or for a fee, creating a new
  business model.

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Using Online Storage Services

• Users access the online storage space using an
  FTP client program, a program or other interface
  provided by the provider, or a Web browser.
• The space is secured with an account name and
  password and permits the sharing of files by many
  users.
• Many businesses rely on online storage services
  to send and receive large files while employees
  are traveling or as a normal course of business.

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Using Online Storage Services

• Many individuals use online storage services to
  store computer backup files, collections of sound
  files, personal Web sites, and other data.
• As a result of bandwidth problems, many online
  storage providers have changed their policies to
  limit the number of transfers and amount of space
  provided, to charge a small monthly fee for use
  of the space, or a combination of both.
• Some online storage providers come and go on a
  regular basis so it is important to backup
  important files and keep a copy of them locally.

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Online Storage Providers

• Some popular online storage providers are
• Xdrive Technologies
• My Docs Online
• Yahoo! Briefcase

links for learning about xdrive services and
features
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Collaborative Authoringon the Web

• Using the Internet to collaborate on files has
  been discussed since the first Web browser was
  created in 1994.
• Collaboration a method for multiple developers
  or authors to work on the same file without
  having to download it, edit it, and transfer it
  back to the original author(s).
• The desire for transferring and editing files
  over the Internet using the HTTP protocol led to
  a new protocol for the Internet known as WebDAV.

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Collaborative Authoringon the Web

• WebDAV (DAV)
• stands for Web Distributed Authoring and
  Versioning
• a standard extension of the original HTTP 1.1
  protocol that is used to transfer Web pages over
  the Internet
• Because HTTP has built-in features that provide
  security and other desirable features during file
  transfers, it provides collaboration features on
  the Internet.
• WebDAV Working Group the group of individuals
  who are actively collaborating on defining this
  new protocol.

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Collaborative Authoringon the Web

• The WebDAV Working Group is dedicated to
  developing and improving the WebDAV protocol on
  the Internet to create an operating-system
  neutral form of collaborative authoring.
• Internet Engineering Task Force (IETF) a large
  group of individuals who contribute to the
  evolution of new and existing Internet
  technologies.
• Four important features that make the WebDAV
  protocol desirable are file locking, properties,
  name space management, and collections.

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Collaborative Authoringon the Web

• The Web Publishing Wizard, which is part of the
  Windows XP operating system, lets you transfer
  files directly to an Internet server using the
  HTTP protocol.
• Windows refers to WebDAV as Web folders.
• To download a file using Windows XP and the HTTP
  protocol with WebDAV, you can create a network
  place, which is a shortcut to a Web site, FTP
  site, network location, or online storage
  provider.
• After creating the network place, you can
  download, upload, and share files at the network
  location you defined.

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Summary

• You can use a Web browser and an FTP client
  program to transfer files between computers
  connected to the Internet.
• You can use a download site to evaluate freeware,
  shareware, limited edition, and full use programs
  based on your needs.
• You can use online storage providers to store
  files that you can share with other users.