CMSC212: Intro to Low-Level Programming Concepts

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CMSC212 Intro to Low-Level Programming Concepts

• Section 0101 900am 950am
• Section 0102 1000am-1050am
• Monday Wednesdays
• Room 3118

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Using the Mac laptops

• Sign-out a laptop if you dont have one
• Hand in student ID
• If wireless is working, then good
• If not, do the following
• Plug the AirPort base station into the network
  using the Ethernet cable and into your WAN port
  (sun-like emblem)
• Networks show up under the Airport indicator as
  UMD CS Mobile Lab 1 or UMD CS Mobile Lab 2
• Password is wireless

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Using the Mac laptops

• Authenticate via firefox
• Start up X11 by clicking the X11 utility in
  /Application/Utlities
• In the window titled xterm, run the following
• ssh X directoryID_at_grace.umd.edu where
  directoryID is the UMCP directory ID (same as
  GLUE account name)
• If X forwarding isnt working, log out/in and use
  the Y option in the login command ssh Y
  directoryID_at_grace.umd.edu

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Using the Mac laptops

• If using Terminal (/Applications/Utilities)
• Set DISPLAY variable with command export
  DISPLAY0
• ssh -Y directoryID_at_grace.umd.edu

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Configuring GLUE accounts

• Login to linux.grace.umd.edu
• Environmental variables
• Set of dynamic named values that are inherited by
  processes
• Some common ones for UNIX
• PATH Lists directories that the shell searches
  for commands the user may use without supplying a
  full path
• HOME Path of the users home directory
• MAIL Path of users mail directory

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Configuring GLUE accounts

• Displaying environmental variables
• env, set, printenv
• Edit the .path file (emacs .path )
• add the following (in one line) to the end of
  file
• setenv PATH /afs/glue/class/fall2009/cmsc/212/010
  1/public/binPATH
• This will add the coursework bin folder in front
  of the existing path variable
• Put a newline at the end of file (hit return)

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Configuring GLUE accounts

• Check via the command
• source /.path
• rehash
• env
• which submit
• Should print /afs/glue/class/fall2009/cmsc/212/...
  
• Symbolic links
• File that contains a reference to another
  file/directory
• Similar to Window shortcuts and Mac aliases

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Configuring GLUE accounts

• Create a symbolic link to the course directory
  from your home directory called 212public
• cd
• ln s /afs/glue/class/fall2009/cmsc/212/0101/publi
  c/ whitespace 212public
• Testing the link
• cd 212public/..
• pwd
• ls

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Configuring GLUE accounts

• Disk space
• Given extra disk space every semester if you have
  a class using the Grace systems
• Extra disk space backed up every night
• Extra space located elsewhere on system so use a
  symbolic link to get to it
• ln s /afs/glue/class/fall2009/cmsc/212/section/s
  tudent/loginID/ whitespace 212

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Configuring GLUE accounts

• Checking this
• cd 212/..
• pwd
• If retaking the course, dont use the extra disk
  space from previous semester as it will get erased

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Configuring GLUE accounts

• The .cshrc file
• File read by the Unix shell every time you login
• Edit .cshrc.mine file (emacs .cshrc.mine )
• Add the following tap q java
• Newline
• To check
• source /.cshrc.mine
• rehash
• which java
• Should print
• /afs/glue.umd.edu/software/java/current/sys/bin/ja
  va

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Announcements

• Larry has office hours today 420-520 pm
• TAs office hours begin Tuesday and will be
  posted online or in lecture

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• Questions?