outline

Why Unix?

• defacto web server standard
• reliable
• inexpensive

Why FTP and telnet?

• most of us not directly on server
• allows us to connect to server from a client
• we can work on client -> send to server
• can work directly on server

Operating systems in general

• 'trafic cop'
• control interactions between files, hardware, software, memory
• provide user interface
• all have similar capabilities, very different implementations

Review of hierarchies

• tree picture?
• Yahoo search

Hierarchy searching algorithm

• find the root
• look at branches
• three outcomes:
• o target is there - activate it
• o not there, but promising subcategory - go there and repeat
• o not there, nowhere close - back up a level and repeat

This is a recursive algorithm

• starts with large set
• algorithm repeats on increasingly smaller subsets
• eventually a trivial set remains

Other trees...

• menus inside applications
• start & apple menu
• directory structures

Text based operating systems

• DOS and UNIX
• Basically the same things available
• Instead of graphics, you need commands
• Some memorization (or cheat card) necessary

Exploring ds9 with FTP

• graphic FTP programs
• Basically two file management programs

Exploring ds9 with Telnet

• use of commands to implement same concepts
• link to java telnet client???

The critical unix commands

• ls
• cd
• pwd
• cp
• mv
• chmod

One slide per command

• all relevant info at http://www.cs.iupui.edu/~aharris/webDesign/ht2.html
• (Just move it over)

Permission settings

• The three types of people
• me
• group
• others
• The three settings
• read
• write
• execute (run if it's a program, go through if it's a directory)

Interpreting permissions:

• I can do anything,
• my group can read and write, but not execute
• everyone else can only read it
• rwx|rw-|r--
• 111 110 100
• 7 6 4

Common permission settings

• 711 - used for main directory
• 755 - used for public_html directory
• 644 - used for almost all html files and graphics
• If in doubt, a directory can be set at 755, file at 644

your directory settings

• set your main directory to 711
• create a public_html directory
• set its permission to 755
• FTP your graphics to the public_html directory
• set their permission to 644