Introduction to ?EPS? Computing:
Networks:
- A Network is a system of at least two divices that communicate between each other. The divices can be separated by meters (Local Area Network - LAN) or kilometers (Wide Area Network/Internet).
Each computer on the network has a name. For example, "george". One the computer is on a network, it has a domain extension. For a generic univeristy domain, full name will be "george.university.edu", or for a company "george.company.com".
- The same is true for web addresses. Many web adresses start with "www". This is a computer name, such as "www.google.com".
- Most computer networks use TCP/IP network protocal. This is a binary communication protocal that gives every computer a specific nummeric address, 123.456.789.012. Information is sent from one numeric address to another and then back.
- A server controls the access other computers have to the rest of the network.
- A hub or switch splits one line into many, so that multiple computers may interact with each other.
- A Firewall is a secure box that only allows particular information in and out. This is the first line of defense against attacks from outside hackers.
- Printers may be connected directly to the internet or shared through other computers.
The department has a wired & wireless network. What is a network?
Logging on to a computer
- Every computer in the department must be password protected (including your own). If it is not, anyone can use it for malicious purposes.
- Your user name should be something like first_initial_last_name.
- Your full user name is computer dependant: user@computer.edu.
- Your email is given by the same user name: user@domain.edu.
- Your password should have symbols, numbers, & UPPER and lower case letters. This makes them much harder to hack! NEVER use common words (god, geology), number sequences (1234), or names (your name).
File Structure:
- File structure is dependent upon the opperating system. Accademic institutions typically have Windows, Mac, & Unix/Linux systems.
- Folders contain other folders & files. It is crucial to keep your file structure organized. Otherwise you won't be able to find anything. The number of files you accumulate over 5 years is staggering!
- Some files you do not want to change and won't have permission to change!!!! System files/folders are intended to be located where they are and YOU WILL SCREW YOUR SYSTEM UP IF YOU ALTER SYSTEM FILES. Rule of thumb: If you don't know what the file does, don't mess with it.
- You will want to only mess with files in your own working directory, which is usually under: /Users/username/ or C:\username.
Secure File Transfer Protocol:
- In order to transfer files from one computer to another, you will need
to use a file transfer protocol. Secure file transfer protocols are much
more safe (from hackers).
For Mac I recommend Fugu:
For PCs I recommend Putty:
Connect to your server. $server$.$university$.edu. You will need to enter your short user name and password. On the left side of the GUI interface is your file structure on your local computer. On right side of the GUI window is the remote computer. You will start out in your own working directory on both computers:
- /Users/username/
Once logged on, the program should look something like this:
On the left side of the screen your local file structure is displayed. On the right side the remote system's file structure is displayed. You can transfer files between the two by dragging and dropping from one side to another. STOP & READ THE REST BEFORE YOU DO ANYTHING ELSE. The files you copy will overwrite any pre-existing files. You will loose all information in the old file, only retaining data from the new file. Be very careful when transfering back and forth.
Double click (left mouse button) on the "Public" directory in the remote system window (right window). This will move you into the "Public" directory. Note that the menue above the left window now says "Public". To move back to the "Parent Directory", or the directory containing (above) the "Public" directory, click on the arrow up near the top right. Alternatively, you could select the menue above the right window and select the option above "Public", which should read as your user name.
xterm & Secure shell:
It is userful to have a text-based command prompt for doing research. Many simple programs are easiest to develope and run from a text-based system. I recomend a unix/unix-like terminal. I use xterm on a mac & Xthinpro on a PC. On Mac OSX xterm must be installed from the install disk. xterm resides in the "Applications" folder under the subfolder "Utilities".
In the new terminal window, type 'ls' at the prompt.
. The directory names are equivalent to those seen on the left side of the SFTP window. To move into the "Public" directory type "cd Public". To move back to the parent directory, type "cd ..". 'cd' stands for change directory. Typing "cd" alone will move you back to your main starting directory.
To log onto a different computer, type: "ssh -AY $server$.$university$.edu", and then enter your password. Note, if your user name is not the same on the other computer, type "ssh -X username@$server$.$university$.edu", and then your password. The "-AY" automataically transfers graphics back to your local computer.
If you entered the correct user name and password, you will now have a new prompt. Any command you type at this prompt will be executed by the remote computer.
Change directories into the "Public" directory on your local machine (cd Public). Type "nedit index.html". This will open a GUI text editor. Copy the text below into the text editor.
<HTML> <HEAD> <TITLE>Sample Web Page</TITLE> </HEAD> <BODY BGCOLOR="#FFFFFF"> <HR> <P> Users Web Page, change this text. <HR> </BODY> </HTML>
Change the text from "Users Web Page, change this text" to something distinctive. "My Web Page", "The Darth Vader Fan Club", "Geoscience is my life".
Now write the following web address into your browser (change username to your user name on the server):
- http://$server$.$university$.edu/~username/index.html
Does anything show up? If not, type the following in the terminal (in the "Public" directory on the remote server): "chmod 755 index.html" and then "chmod 755 ../Public". This will change the permissions so that everyone can view and execute the file, but only you can change it.
Now you have a web site on http://$server$.$university$.edu.