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Introduction For New Users

Finding Help and News

Reaching Us: Consultants On Call

Consultants are on duty Monday through Friday, between 8 AM - 5 PM Alaska time. Contact User Support for more information.

MOTD or Message Of The Day

The MOTD appears each time a user logs onto a machine. The MOTD is updated frequently to keep users informed. Review the MOTD at any time by entering the following command at the shell prompt:

cat /etc/motd

News

On any ARSC machine, type news | more to read all unread news items, one screen at a time.

Reading a news item marks it as read, therefore running this command clears the list of unread items presented upon each log on. Thus, only new and updated items will be presented during the user's next login.

To read any particular item, type news item | more, where item is the name of the news item to be read. When running jobs on an ARSC system, it is a good idea to check the upcoming and most recent downtimes for each system with news downtime | more.

System News, On The Web

System news is also available online.

ARSC HPC Users' Newsletter

Offering current information for ARSC users and the wider HPC community, this bi-weekly newsletter is available via email subscription and online.

ARSC HPC Users' Newsletter

Training

ARSC provides one-on-one training upon request, formal seminars, and short-courses throughout the year. See our Training and Classes list for upcoming scheduled classes.

Connecting and Logging On

Default Passphrase Letter

After filling out the appropriate paperwork, a new user will receive an envelope containing their default passphrase (or kerberos password) and SecureID card. Read and save the default passphrase letter for future reference.

See also: Account Activation/Passphrase Distribution.

SecurID Card

For information about the SecurID card, see the HPCMO Kerberos and SecurID information center web page. From their introductory page, click on the "Documentation" bullet on the left hand side, then click on the "HPCMP Kerberos FAQ" bullet under the "HPCMP Documentation" section.

During login, you will be asked for your SecurID passcode. To generate this number, type your PIN (included in the passphrase letter) into the SecurID card, then press the diamond shaped symbol. The new six digit number appearing on the SecurID card's display is your current SecurID passcode. Enter this six digit number at the command prompt to complete your "kinit" login.

Please contact User Support if you have forgotten your SecurID PIN or if someone else discovers it. We can easily issue you a new PIN.

Logging on With Your SecurID Card and Kerberos

Every user logging into an ARSC or DoD system must use Kerberos, a computer security protocol. For instructions on downloading and installing Kerberos, see obtaining Kerberos Client software and the Kerberos5 Quick Start Guide.

During login, the user must authenticate their identity associated with their principal realm (i.e. ARSC, HPCMO, NAVO, etc.) To do this, the user will provide their principal (usually equivalent to their user id), their passphrase (kerberos password ), and a passcode (generated on the SecurID Card by entering their PIN). Once authenticated, the user will be issued a kerberos ticket, granting them access to ARSC systems for the lifetime of the ticket.

Changing the Passphrase (or Kerberos Password)

After logging into an ARSC machine, type kpasswd at the command prompt to change your passphrase. For assistance in choosing a more secure password, see ARSC's tips for memorable passphrases.

Terminal Settings

The Unix operating system supports an environment variable known as TERM. This variable contains information indicating the type of terminal, console or display-device being used. To view the current terminal setting, type echo $TERM at the command prompt. Common values assigned to the TERM variable are vt100 and xterm. To set the TERM variable from the command prompt in c-shell or tcsh, type setenv TERM vt100, or in bash or korn-shell, type export TERM=vt100.

Connecting with SSH and using X Windows

If you wish to run X Windows Applications, we recommend connecting with the Kerberized version of ssh. Please note that in most cases the client kit and Kerberized ssh are two separate downloads and are both required to connect to ARSC systems. To avoid problems while running X Windows Applications over ssh, be sure to connect using the "-XY" option. For example:

ssh -XY midnight.arsc.edu

If system compatibility issues prevent a connection using ssh, alternate connection options are available. Please contact User Support for further information and assistance with remote connectivity to ARSC systems.

Using X Windows and MS Windows Operating Systems

If you wish to use X Window based applications from a system running Microsoft Windows, you must have an X11 client as well as the HPCMP Kerberos kit. There are several X11 clients available for Windows including the Exceed X-Server and the freely available Cygwin X11 server. For instructions on configuring and setting up X Windows using Cygwin, please view this document.

Checking and Forwarding Email

Your ARSC systems account also comes with an email account. Email sent to your ARSC email address can either be forwarded to a different email address or stored on ARSC's email server, where it can be accessed via IMAP from an ARSC system. For instructions on setting your forward email address or configuring an email client to check an IMAP email account, please refer to email services at ARSC.

Getting Started on ARSC Systems

Available Hardware

See ARSC's current line-up of HPC and other user systems.

"Getting Started Guides"

Find your system in the list of Getting Started Guides.

Operating Systems at ARSC

All ARSC HPC systems run variants of the Unix operating system.

Running a Program

The current working directory is not included in the user's default PATH. Therefore, to run a program interactively (even if the executable is in the current default directory), the path to the executable filename must be specified. For example, to run a program titled a.out from the current directory, type:

./a.out

See also: Dot (".") Not In Default PATH.

Sample Codes

As an aid to new (and experienced!) users, ARSC maintains a respository of sample codes on each major HPC system.

Batch Processing

To submit a batch job on any of the HPC systems, you will create a script containing formatted information regarding the size and duration of the job to be run, and the commands needed to execute the program. See the "Getting Started" pages for your system for instructions and examples.

Storage Management

Storage is an important, finite resource. Please maintain an understanding of the various storage mechanisms available, and use the storage systems efficiently. For further details, see the Storage Management document.

Limits, Restrictions, and Administrivia

Managing Your Allocation of CPU Hours

See Resource Accounting page.

Quotas: Monitoring Disk Space

On the systems implementing quotas, a user may view their disk space allocation by using the quota -v or qcheck commands (see each machine's getting started guide for the appropriate quota query.)

For details on ARSC's implementation of quotas, please see the Storage Management documentation.

Disk Usage Monitoring

The du command displays the total storage used within a directory and all of its subdirectories.

Useful options include -k, which displays the storage in kilobytes instead of blocks (1 block = 512 bytes) and -s, which provides a brief summary listing.

Filesystem Purging Policies

View Storage Management for a summary of filesystems and the frequency of purging old and unused files.

Home Directory Permissions

You must be careful not to set write permissions on your home directory. Please see the policy on home directory permissions for more information.

Enforced Policies

ARSC users must abide by certain policies affecting overall system security and the use of shared resources. The following documents are required reading:

System Maintenance and Downtime

ARSC supercomputing systems are usually taken offline for preventive maintenance on Wednesday evenings from 6:00 PM - 10:00 PM Alaska local time. Workstation systems are scheduled to be taken offline as needed with as little impact on users as possible.

We notify users as early as possible via the "message of the day" (MOTD) if we are scheduling preventive maintenance downtime. Type news downtime | more at the shell prompt on any system to view recent and planned downtimes for that individual system.

More Information

Please contact User Support if you encounter any problems or have any questions during your computing experience with the Arctic Region Supercomputing Center.

 

Arctic Region Supercomputing Center
PO Box 756020, Fairbanks, AK 99775 | voice: 907-450-8600 | email:

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