Overview

SAS Computing operates and administers several UNIX workstations used by the Math Department faculty, staff, and students. These machines include: This document will refer to this group of machines as the Math Unix Systems.

Mail Quotas

Each user on hans.math is subject to a 10 MB quota for their incoming mail file (mail spool). Users' mail spools are located in /var/mail. Users will receive a warning message when they reach 7 MB. A final notice will be sent when users exceed 10 MB. User mail spools will be locked within 7 days of receiving the final notice.

Disk Quotas

Each grad student account has a quota of 150 megabytes of disk storage (for faculty, 450MB). Users who exceed this limit for over 7 days will have all write privileges to their account turned off until below quota. Linux-Terminal Users: if you go over quota you will not be able to log in. You should log into hans via ssh and adjust your quota as documented below.

If you are over quota when you log into your account, you will see a message indicating the amount you are over quota, as well as the amount of time left before the above restrictions take place. You will also see a warning during your session if you exceed quota (on hans).

Managing quotas on hans

The command quota_total will tell how much space you are currently using.

The command du -sk * will tell how much space (in kb) individual files and folders are using.

Note that using rm to delete files does not necessarily reduce quota. See Deleting Files for further information.

If it is determined that after cleaning the account and compressing files that a larger quota is necessary, please send your request to quotas @ math . upenn . edu


Print Quotas

Users have a per-semester allocation of pages they may print, based on the following classifications:

CLASSIFICATION PAGES
Math Graduate Students who are teaching 400
Math. Graduate Students who are not teaching 300
TAs who are not Mathematics Graduate Students 150
Undergraduates 100
Guests (includes Math Graduate Students on leave) 100
REMARK: Here, the summer is counted as a third semester. The "teaching" status only applies to the semesters in which one is teaching. For many TAs, it will not apply for the summer.

In addition, a one-time dissertation supplement of 300 pages is available.

More information on printer usage can be found in the Printer Usage Guidelines document under Print Quotas.


Security

Your computer account is for your use only. You are solely responsible for what is done using it. If there is evidence of unauthorized or improper use of your account (including account sharing), it may be temporarily disabled. This protects your files and other users of the system. You will be asked to contact the manager AT math . upenn . edu, change your password, and/or take other appropriate action. If you suspect that someone else may be using your account, report it by contacting the manager AT math . upenn . edu immediately.

Choose a password that will be difficult to guess and keep it a secret. Your password belongs to you alone. Don't even give your password to a friend or to a computer system administrator.

If a system manager asks you to discontinue any activity on the system, you must stop or risk account deactivation.

Log out when you are finished at a terminal. If you don't, other people can use your account, change or delete your files, and so on.

No computer system is immune to forgeries or spoofs. Don't take any irreversible action based on electronic communication alone. In particular, don't believe everything you read on April Fools' Day.


Privacy

Read other people's files only if you have permission from the owner to do so. This applies to both protected and unprotected files. On the other hand, complete privacy cannot be guaranteed. Never store files on any time-sharing system whose disclosure would be disastrous. The system manager will only view users' files under exceptional circumstances, such as the appearance of abuse, for required system maintenance, or in response to a question or request from the user.

Accessing Other Computers

Only attempt to connect to other computers if you have reason to believe that the owner wants you to connect. This includes http (World Wide Web), telnet, ftp, login, and any other method. If you are requested to stop connecting to certain computers, you must stop.

You may not run any server program which accepts incoming connections to any of the Math Unix Systems. Failure to comply with any of these rules may result in suspension of your account privileges.

All outside connections go through the Internet, and some machines on the Internet have very strict policies. Since our university connection can be terminated by Internet authorities if there is evidence of abusive use of the connection, SAS is very strict about even the appearance of abuse.


Misbehavior

Forged mail, attempts to use other people's accounts (including superuser), attempts to crack passwords, attempts to alter system files, and similar misbehavior may be referred to the University Judicial Inquiry Office.

Other misbehavior may violate the University's general policies, the Pennsylvania Computer Crime Act of 1983, the University's Acceptable Use Policy or other applicable laws.

Any activity which denies or restricts service to other users of the Math Unix Systems or any other computer is strictly forbidden. This includes harassment by repetitive email, electronic chain letters, talk, write, or any other means. Harassment by computer falls under the university's general policy. Severe or repeated harassment will be referred to the Ombudsman's Office. Any concerns about this may be discussed in a confidential manner with the Ombudsman's Office (898-8261).


Processor Time and Memory

There are no strictly enforced limits on CPU or memory usage. Users are asked, however, to run 'intensive' processes on the linux terminals and not on hans.math. 'Wild' processes found on hans may be niced or killed by the system administrator.

To run processes remotely, users should connect to the remote linux terminal with X-forwarding using: ssh -X


Idle Session Logout

Idle login sessions may be automatically terminated after 14 days, or sooner for machines in the public labs.

File Backup and Retrieval

If you delete a file by mistake, you can restore it yourself if you do it promptly. Deleted files remain on the system until early the next morning. See zap.html for details.

File retrieval service is available for occasional accidental deletions of critical files. Retrieving data is time and labor intensive, so these services are limited, and subject to the judgment of system administration personnel. See Server Backup Procedure for more information.


Automated Enforcement and Other Policies

Some of the stated policies and limits are automatically enforced, and others manually at the discretion of the administrative personnel. Even if the automatic enforcement programs are circumvented, the policies still apply. There is a policy for use of the the NSFnet (our connection to most non-Penn computers), available from SAS. The University's general policies apply to computers, such as the policy on commercial use of facilities, guidelines on open expression, and the code of academic integrity.

Page last updated: March 07, 2003