Lecture Notes - Tues Jan 28

• Roster - if your name isn't here, then you still need to email me.
• Questions from last time?
• Homework - please send it in. Next week's is posted.

• Finish Jan 23 lecture notes.
• High points:
  • URI's like http://www.google.com/
  • IP Addresses like 12.6.230.2
  • DNS - Domain Name System, mapping URI's and IP Addresses
  • data : bits, bytes, files,
  • file systems : local and remote computers and directories
  • Internet concepts : networkds, packets, routers, protocols, bandwith

• Class exercise 1:
  time to transfer a CD by campus net? (CD is roughly 3600 sec of sound at 44000 Hz or around 1 Gigabyte. Ethernet is 10 or 100 Mbps.)
• (Aside: how big is a DVD? How many books is that?)
• Class exercise 2:
  321 base 10 = ? in base 64? in base 2?
  1111000111 base 2 = ? in base 10?
• See Base Conversion Tool

• Recipe for turning on your web accounts on akbar.

   1. Use SSH to connect to akbar, with your username/password account.
   2. Type "ls -ald".  Do you see "drwx---r-x" ?
   3. If not, type "chmod o+rx ."  (You do need to type the period.)
   4. Now type "ls -ald html".  Does it say "html: no such file or directory"?
   5. If so, you need to create one.  Type "mkdir html".
   6. Make sure it looks OK.  Type "ls -ald html" again.
      The last few characters in the permissions should be "r-x".  If not, 
      type "chmod o+rx html".   

• Things you can type at the akbar (unix) command line (optional)
  • ~ means your home directory
  • ~fred means Fred's home directory
  • . means the current directory
  • .. means the directory above this one
  • ls - list current directory
  • pwd - print working directory
  • cd - change directory
  • mv - move a file
  • cp - copy a file
  • chmod - change file permissions
  • man - look something in the online manual (or just use Google)
  • finger - look up someone else on this computer
  • df - how much disk space is free?
  • du - how much disk space am I using?
• We'll test this in class; I'm not quite sure what the default set-up is now on akbar.

• Your files on akbar are accessible by...
  • web browser, if they're in html/.
    (At the address http://www.marlboro.edu/~username/)
  • SFTP (Secure File Transfer Program) - to move them to/from
  • SSH (Secure Shell) command line, to manipulate them in place
  • Mounting them on your desktop, as a remote file system. (See campus tutorial.) Only owner can do so; then you can do to them pretty much whatever you can do to local files.

• Publishing online: the basic steps
  1. Create a .html (text) file using an editor, on your local machine.
  2. Move that file to your html directory on akbar.
  3. See if you can see it with a web browser.
  We'll go over each of these in turn.
• Variations on this theme:
  • You can edit/create the .html files with a WYSIWYG editor, i.e. Composer or DreamWeaver.
  • You can mount your akbar directory, and work on the files as if they were local.
  • You can log in to akbar, and edit them there with programs like "vi" or "emacs" or "pico".

• Special file names (these depend on the server configuration)
  • index.html - if no file name is given in the URL, and this file exists, it is displayed instead of the directory listing.
  • README - appended to directory listings
  • HEADER - prepended to directorylistings

• HTML markup 101 (if we get this far)