faq
questions
some answers
Here's some step-by-step instructions.
There are many, many computer labs located on campus.
Here's a list:
http://www.columbia.edu/acis/facilities/labs/locations/.
The homeworks should be submitted using the Columbia CUNIX computer system.
If you are logging into the CUNIX system from your own computer, you will
need some kind of terminal emulator program to interface with the CUNIX system.
We recommend using TTSSH, which is a secure program.
Information on TTSSH
(a nice, secure telnet program for windows)
Download TeraTerm (version 2.3)
(needed for TTSSH)
Download TTSSH
(Secure SHell (SSH) extension to TeraTerm)
Once you've dowloaded and installed TTSSH, you can log in from home. Connect to the Internet, and then run TTSSH. The hostname you want is "cunix.cc.columbia.edu", and you should click the "ssh" to indicate that you want to run a secure shell (connection).
unix$ export PATH=/opt/jdk1.3.1/bin:$PATH
(Note that each of these commands should appear all on one line, though your browser window may seem to split them up into two lines.)
Then you can confirm that you are picking up the right version of java by typing:
unix$ which javac
And you should get back this:
/opt/jdk1.3.1/bin/javac
You have to set these environment variables every time you want to use the jdk version 1.3.1,
since the system default is to use jdk1.1.5 (that is, once per login session).
It is simplest to edit a file called .profile to set these automatically every time
you log in. Your .profile file resides in your home directory, so do the following:
unix$ cd $HOME
and then add these two lines to the file:
export PATH=/opt/jdk1.3.1/bin:$PATH
(Note that each of these commands should appear all on one line, though your browser window may seem to split them up into two lines.)
You need to make sure that these environment variables (PATH and LD_LIBRARY_PATH) are not being set
anywhere else in your .profile and thereby ignoring your settings.
If you find other lines in your .profile that begin with the words "export PATH" and/or
"export LD_LIBRARY_PATH", then comment them out by placing a "#" character at the beginning of
the line.
Similarly, make sure that these environment variables are not being unset anywhere else in your
.profile and thereby ignoring your settings.
If you find any lines in your .profile that begin with the words "unset PATH" and/or
"unset LD_LIBRARY_PATH", then comment them out by placing a "#" character at the beginning of
the line.
Then try logging out and logging back in again and then confirming that you are now picking up the
right version of java by typing:
unix$ which javac
And you should get back this:
/opt/jdk1.3.1/bin/javac
(1) To use appletviewer, you need to be running on an X-windows enabled computer.
If you are not working on a UNIX computer, you will need an X-windows emulator.
For a Microsoft Windows machine, the popular emulator at Columbia is XWin-32.
Unfortunately, this is only free for use on CS department machines.
(2) If you don't have access to XWin32 or a native X-windows machine, then you
can still see your applet using a browser.
Copy your HTML and your class files to your home "public_html" directory,
as we discussed in class.
Make sure these files are both public read access
(chmod a+r hi.html hi.class), as we did in class.
Now you can load them in your browser,
e.g. http://www.columbia.edu/~eis2003/hi.html.
If you want to print on campus...
AcIS provides printing capabilities from CUNIX computers.
Information is here:
http://www.columbia.edu/acis/facilities/printers/jake.html
If you want to print from home...
If you are logged into CUNIX and running TTSSH, but you are working from home,
the program you have been writing (e.g., hw1eis2003.java) will be located
(stored) on a CUNIX disk, NOT on your home computer's disk.
You can wait until you come to campus and print it out here, using one of the
printers as described in the paragraph above.
Or you can download your program from the CUNIX system onto your own
computer.
Step-by-step instructions below assume you are using TTSSH and a windows
computer (see the answer to the "what is telnet" question, above).
(1) On the TeraTerm "File" menu, select "Change directory", and enter the
location of the directory on your windows computer where you'd like your
homework file to be downloaded.
(For example, I typed in "c:/sklar/teaching/cs1007/hw".)
(2) At the unix prompt inside your TeraTerm session, type "sz
(3) On the TeraTerm "File" menu, select "Transfer", then "ZMODEM",
then "Receive".
A little window should pop up and show the progress of the download.
When it's done, the window should go away automatically.
This should happen really fast, because the file is relatively small.
Trouble?
If the window doesn't go away after a couple of minutes and it looks like
things are hanging, try clicking on "cancel" and trying again.
Once you've typed the "sz" command at the unix prompt, if the file transfer
doesn't finish (i.e., you've clicked "cancel"), it is likely that your
TeraTerm window will hang. So you'll need to close it and log into CUNIX
again. Sorry :-(
(4) Back in the TeraTerm window, you should be able to hit return (enter) and
get the unix$ prompt back.
If you have been working on your own computer, then your homework is located
(stored) on your computer's local disk.
You will need to upload your homework from your own computer onto the
disk associated with your CUNIX account.
The step-by-step instructions below assume you are using TTSSH and a windows
computer (see the answer to the "what is telnet" question, above).
(1) Connect to the Internet and log onto your CUNIX account using TTSSH.
(2) Go to the directory (on your CUNIX account) where you want to upload
your homework file. (For example, I would type: "unix$ cd cs1007/hw".)
(3) At the unix$ prompt, type: "unix$ rz"
(4) On the TeraTerm "File" menu, select "Transfer", then "ZMODEM",
then "Send..." and select the file you want to upload.
A little window should pop up and show you the progress of the upload.
When it's done, the window should go away automatically, and inside your
TeraTerm window, you should get the unix$ prompt back,
There are two steps necessary, both involve changing what are called UNIX
environment variables.
When running in a UNIX environment, the unix$ prompt is provided to you
by something called a shell.
The default shell on the CUNIX system is called bash
(although there are many other shells around).
This is why you may have sometimes gotten error messages that start with the word bash:,
which indicates that the bash shell is reporting the error to you.
Anyway, the behavior of the shell is controlled by various settings, whose values are stored in
variables called environment variables.
In order to be running jdk1.3.1, you need to set two environment variables:
PATH and LD_LIBRARY_PATH.
You do this at the unix$ prompt, by typing the following two commands:
unix$ export LD_LIBRARY_PATH=/usr/lib:/usr/openwin/lib:/opt/local/lib:/opt/ACISX11R6.1/lib
unix$ emacs .profile
export LD_LIBRARY_PATH=/usr/lib:/usr/openwin/lib:/opt/local/lib:/opt/ACISX11R6.1/lib
In order to see an applet, you need an HTML file to invoke it, as we've done
in class (see lectures #13 and #14).
You can use either (1) the appletviewer program or (2) a browser to view the
applet.
If XWin32 is already installed on the machine you are using (you will know
because there will be a little blue X in the lower right corner of the task bar),
then you need to do the following:
First, double click on the little blue X, which should bring up an XWin32 window.
Click on the "Display" tab, then click on "Copy", the click on "Okay".
Second, in your TTSSH window (where you are logged into your CUNIX account),
type:
unix$ export DISPLAY=
then (without pressing ENTER!), click on "Edit/Paste", which will paste in the
IP (Internet Protocol) address of your display (i.e., the computer you are
sitting at) into the TTSSH window after the "DISPLAY=" which you typed above.
Now press ENTER.
Third, you can start up appletviewer by typing:
unix$ appletviewer hi.html
or whatever is the name of your HTML file.