CS230 Data Structures, Wellesley College, Fall 1999

CS230 File Server

[CS230 Home Page] [Assignments] [Documentation] [Software Installation] [FAQ] [CS Dept.] [CWIS]

 

CS230 Server Basics

cs230.wellesley.edu is a file server where CS230 students may store their files during the semester.

Accounts and Passwords

In order to store files on the CS230 server, you need a CS230 server account name and password. Your CS230 server account name is the same as your Lucy account name, except in the case where your Lucy account name is more than eight characters long; in this case, it is the first eight characters of your Lucy account name. For example:

Student Name

Lucy Account Name

CS230 Server Account Name

Georgia Dome

gdome

gdome

Abby Stracksen

astracksen

astracks

You have been asked to choose a password for your CS230 server account. Your CS230 server password should be at least 6 characters long, should not be easily guessable by person or computer (no English words, people or place names, or dates), and should be different from the password for your Lucy account.

Examples of bad passwords: CS111, computer, sesame, abracadabra, Wellesley, Georgia, 092378

Examples of good passwords: kriptyk, javarama, Interknet, 17Abby23, UpAnDdOwN, gwrkt79

Both account names and passwords on the CS230 server are case sensitive. Your account names consist only of lowercase letters. Your passwords may contain both lowercase and uppercase letters, but you must get the case of each character right in order for the password to be accepted.

If you forget your password during the term, please contact your instructor.

Directories

A CS230 server directory is a structure that contains files and other directories. It corresponds to a folder on a Mac. Associated with every CS230 server account is a home directory in which files for the account are stored. Whenever you connect to the CS230 server via an FTP client (see below), you will be connected to your home directory by default, though it is possible to navigate to other directories as well.

The name of the home directory is the same as the account name. All home directories on the CS230 server are located within another directory named users, which itself is located in a top-level directory named usr. Directory and file names are often specified as a path name containing the sequence of directories that must be traversed to get from the "top" of the file system to the desired directory or file. Path names are written with the components separated by slash ('/') characters. For example, Georgia Dome's home directory is /usr/users/gdome, and the CS230 home directory is /usr/users/cs230. The /usr/users/ path prefix is so common that it is abbreviated by a twiddle ('~'). So ~gdome is an abbreviation for /usr/users/gdome.

The CS230 server file system has been preconfigured with a number of special directories. We will illustrate the special directories associated with account gdome; you should substitute your own account name for gdome:

Security

Only you are able to write files to or delete files from your home directory, or any subdirectories thereof. Additionally, only you are able to write files to or delete files from the drop folders with your account name. Any attempt to write files in another students' home directory or drop folders will fail.

Only you (and your instructors -- see below) are able to read files in your drop folders and your private directory (and subdirectories thereof). However, by default, all directories other than your private directory are world readable, which means that anyone may read them. If you want files to be private, you should store them in your private folder.

Note that your instructors have the ability to read, write, and delete any of your files. However, except under unusual circumstances, the only private files of yours that we will manipulate are those that you explicitly submitted to your drop folders.

Transferring Files From/To The CS230 Server

To transfer files between the CS230 server and your local computer, you need to use a File Transfer Protocol (FTP) client on your local computer. An FTP client for Macs is Fetch. An FTP client for PCs is Winsock-FTP. Here is a summary of how to use Fetch to transfer files from and to the CS230 server:

Connecting to the CS230 Server

When you launch Fetch, you will be presented with a dialog window with various fields to fill in. You should fill them in as follows:

Selecting OK will open up a Fetch window connected you to your home directory.

Downloading Files

To copy a file or directory from the CS230 server to your local computer, select the file or directory icon in the Fetch window, drag it to the desktop or local folder, and drop it. You may also use the Get button to download files.

Uploading Files

To copy a file or directory from your local computer to the CS230 server, drag-and-drop the file/folder from the desktop to the Fetch window. You may also use the Put button to upload files. Important warning: sometimes Fetch will complain of a "dropped connection". This happens most often when uploading directories containing numerous files. This error message indicates that not all of the files were uploaded. Whenever you get such a message, you should try the upload again. If you continue to get this error message, you should break the upload into smaller chunks. E.g., rather than uploading a directory with 30 files in a single operation, instead upload 10 files at a time.

As a general precaution, you should always examine the state of the Fetch window after performing an upload to make sure that your files were uploaded properly. If a filename is missing or a file is listed as having size 0 K, this is an indication that the upload was not successful.

Deleting Files

To delete a file or directory from the CS230 server, drag the file/folder into the trash can on your desktop.

Navigating The Directory Hierarchy

By default, the Fetch window is connected to your home directory. You can navigate to subdirectories by double-clicking on the names of the subdirectories within the Fetch window. You can navigate to a parent directory by selecting the directory name in the menu that appears above the listing of files in the current directory.

Quotas

Because storage resources on the CS230 server are limited, each CS230 student account has a 3.5 megabyte (MB) file system quota that cannot be exceeded. This is about the amount of storage on 2 floppy disks. If you keep lots of files, or even just a few large ones (such as images), you may find yourself pushing the 3.5MB limit. An attempt to store a file that will exceed the quota will fail. In this case, you will need to delete some older files in order to be able to store new ones.

Backup Your CS230 Server Files on Floppies!

File servers like the CS230 server sometimes fail. In some cases, they may become inaccessible for long periods of time; in other cases, they may actually lose information. For both of these reasons, we require you to keep copies of all your work during the semester on your own personal floppy disks. That way, if the CS230 server should become inaccessible or lose files, you will still be able to proceed with your work.

Because floppy disks themselves are unreliable storage media, you should make backup copies of your floppy disks on a regular basis during the semester. Since student accounts on the CS230 server will be deleted after the semester ends, you should be sure to save on your personal floppy disks any CS230 server files that you wish to keep for the future.