Computing at UMBC An Introduction to the UMBC Computing Environment CMSC 121 Material source based on slides from Eric Eaton.

Your GL Account GL is short for “General Labs.” This is the same thing as a myUMBC account. Through this account you have access to various computing resources across the campus. GL is short for “General Labs.” This is the same thing as a myUMBC account. Through this account you have access to various computing resources across the campus. Your GL Account gives you access to: Your GL Account gives you access to: Many labs that are maintained by DoIT. An listing of these labs can be found at These labs contain an assortment of dual-bootable Windows XP / Linux PCs and Macintosh's. Many labs that are maintained by DoIT. An listing of these labs can be found at These labs contain an assortment of dual-bootable Windows XP / Linux PCs and Macintosh's. You also get remote server access to several UNIX machines... You also get remote server access to several UNIX machines... linux1.gl.umbc.edu, linux2.gl.umbc.edu, linux3.gl.umbc.edu linux1.gl.umbc.edu, linux2.gl.umbc.edu, linux3.gl.umbc.edu solaris.gl.umbc.edu solaris.gl.umbc.edu The username and password on this account are also your username and password for The username and password on this account are also your username and password for Your username is also your name. You get an account automatically when you sign up for a GL account. It is where username is your logon name. Your username is also your name. You get an account automatically when you sign up for a GL account. It is where username is your logon name.

Your Account Can I change my address? Can I change my address? No. But you can create multiple aliases that send mail to In effect, this changes your address. No. But you can create multiple aliases that send mail to In effect, this changes your To set up aliases, follow the instructions at To set up aliases, follow the instructions at You can also set up your to be forwarded to another account if you wish. See for more details. You can also set up your to be forwarded to another account if you wish. See for more details. Sending and Receiving . There are lots of ways to do this! Sending and Receiving . There are lots of ways to do this! Pine - a UNIX, text-based client. Pine - a UNIX, text-based client. Thunderbird/ Outlook / Apple Mail - GUI. See Thunderbird/ Outlook / Apple Mail - GUI. See Webmail - UMBC's web-based client. It’s easy-to-use, and accessible from anywhere. Webmail - UMBC's web-based client. It’s easy-to-use, and accessible from anywhere. It is strongly suggested that all CS students learn the Pine program. It is very easy to check your mail remotely via ssh, handle attachments, and is very quick and easy to use (well, once you get used to it). It is strongly suggested that all CS students learn the Pine program. It is very easy to check your mail remotely via ssh, handle attachments, and is very quick and easy to use (well, once you get used to it).

The Andrew File System (AFS) ‏ AFS is distributed network file system. AFS is distributed network file system. A file system is simply a collection of files and directories assembled in such an order that they make sense to the operating system. A file system is simply a collection of files and directories assembled in such an order that they make sense to the operating system. AFS manages file storage over the network. AFS manages file storage over the network. Features Features You can access your files using any computer that has an AFS client installed on it. You can access your files using any computer that has an AFS client installed on it. All of the lab and remote login computers: Windows, Linux, Solaris, and Mac, are capable of reading/writing this file system. All of the lab and remote login computers: Windows, Linux, Solaris, and Mac, are capable of reading/writing this file system. The files that you maintain in your account will be accessible to you over the network from any of these computers. No need to store your information on a flash drive and carry it between machines. The files that you maintain in your account will be accessible to you over the network from any of these computers. No need to store your information on a flash drive and carry it between machines.

Your Directory on AFS Every GL account is assigned a directory on AFS, which contains the home directory, web space, and e- mail folders. On all of the UNIX systems here at UMBC it will be located at the following location: Every GL account is assigned a directory on AFS, which contains the home directory, web space, and e- mail folders. On all of the UNIX systems here at UMBC it will be located at the following location:/afs/umbc.edu/users/u/s/username/ u is the first letter of your username, u is the first letter of your username, s is the second letter of your username, s is the second letter of your username, and username is your GL account logon name. and username is your GL account logon name.

Contents of Your AFS Directory These are the folders that are in your account at the time of creation These are the folders that are in your account at the time of creation home - your UNIX home directory. home - your UNIX home directory. Mail – no longer used. Mail – no longer used. pub - this is where public/shared data can be placed, including web space. pub - this is where public/shared data can be placed, including web space. backup - this is a backup copy of your /afs/umbc.edu/users/u/s/username/, updated nightly. backup - this is a backup copy of your /afs/umbc.edu/users/u/s/username/, updated nightly. Within the home directory: Within the home directory: All of the typical files found in any UNIX environment (.cshrc,.login, etc...) ‏ All of the typical files found in any UNIX environment (.cshrc,.login, etc...) ‏ Some are given to you when the account is created. Some are given to you when the account is created. Some are created automagically where applications store user configuration information. Some are created automagically where applications store user configuration information. Your files and directories. Your files and directories.

Contents of Your AFS Directory Within the pub directory: Within the pub directory: it is empty by default! it is empty by default! This is where you can put files, so that others can readily copy them from here into their accounts. This is where you can put files, so that others can readily copy them from here into their accounts. You can also have a www directory within your pub directory that allows you to post files onto the Internet, accessible via You can also have a www directory within your pub directory that allows you to post files onto the Internet, accessible via The backup directory… The backup directory… …is a copy of your entire account, that is read-only and taken from the night before. This is typically done around midnight. …is a copy of your entire account, that is read-only and taken from the night before. This is typically done around midnight. If you were to accidentally delete a file (or screw up a source code file so it no longer compiles) that you had around yesterday you can go into this directory and you will be presented with the home, Mail & pub directories from the day before. You can then simply copy the file from here to wherever you want. If you were to accidentally delete a file (or screw up a source code file so it no longer compiles) that you had around yesterday you can go into this directory and you will be presented with the home, Mail & pub directories from the day before. You can then simply copy the file from here to wherever you want.

Getting to Your Files You should usually save files to your home directory (/afs/umbc.edu/users/u/s/username/home/). How you access your home directory depends on the operating system… You should usually save files to your home directory (/afs/umbc.edu/users/u/s/username/home/). How you access your home directory depends on the operating system… UNIX / Linux / Mac OS X - your home directory is available to you under the /afs/umbc.edu/users/u/s/username/home/ directory. All UNIX shells use this as your default path. UNIX / Linux / Mac OS X - your home directory is available to you under the /afs/umbc.edu/users/u/s/username/home/ directory. All UNIX shells use this as your default path. Windows Windows Your directory (/afs/umbc.edu/users/u/s/username/) is mapped as the network drive "T:" on the Windows PCs. Your directory (/afs/umbc.edu/users/u/s/username/) is mapped as the network drive "T:" on the Windows PCs. Your home directory (/afs/umbc.edu/users/u/s/username/home/) is mapped as the network drive "S:". Your home directory (/afs/umbc.edu/users/u/s/username/home/) is mapped as the network drive "S:". If you have a www directory in your pub directory (/afs/umbc.edu/users/u/s/username/pub/www/), it is mapped as the network drive "W:". If you have a www directory in your pub directory (/afs/umbc.edu/users/u/s/username/pub/www/), it is mapped as the network drive "W:".

Changing Your Password Via the Web Via the Web Logon to click on the Personal tab, then click on Change my Password. Logon to click on the Personal tab, then click on Change my Password. Follow the on-screen instructions for changing your password (there are several steps). Follow the on-screen instructions for changing your password (there are several steps).

If Someone Knows Your Password Change it immediately! Change it immediately! Your myUMBC password is just that - yours and only yours. It should not be shared with anyone. Your myUMBC password is just that - yours and only yours. It should not be shared with anyone. If you think someone knows your password. Here is what you should do... If you think someone knows your password. Here is what you should do... Change your password. Change your password. Report this incident to OIT keeps a log of all activities in all UNIX accounts. Any unauthorized access can be tracked given ample research time. Report this incident to OIT keeps a log of all activities in all UNIX accounts. Any unauthorized access can be tracked given ample research time. You are legally liable for any action caused by your account. You are legally liable for any action caused by your account.

Choosing a Good Password OIT has suggested the following guidelines for choosing a good password... OIT has suggested the following guidelines for choosing a good password Passwords should contain at least: Passwords should contain at least: 8 characters 8 characters One numberal and symbols in the first six characters One numberal and symbols in the first six characters Mixed uppercase/lowercase Mixed uppercase/lowercase Passwords should not be: Passwords should not be: Any words or names spelled forwards, backwards, or in any language Any words or names spelled forwards, backwards, or in any language A Social Security number in the first nine characters of the password A Social Security number in the first nine characters of the password Words constructed with obvious number/symbol substitutions (e.g., 0 for O ; $ for S ; 1 for i ), for example: capta1nk1rk, mr5p0ck Words constructed with obvious number/symbol substitutions (e.g., 0 for O ; $ for S ; 1 for i ), for example: capta1nk1rk, mr5p0ck Note: Passwords are case sensitive. The lowercase ‘c’ is a different letter from the uppercase ‘C’. Make sure that the Caps Lock key is not on, unless you intend to enter all uppercase letters. Note: Passwords are case sensitive. The lowercase ‘c’ is a different letter from the uppercase ‘C’. Make sure that the Caps Lock key is not on, unless you intend to enter all uppercase letters. If you forget your password, the OIT helpdesk can reset it for you. If you forget your password, the OIT helpdesk can reset it for you.

Your Quota Every student with anUNIX account has a disk quota. This is the amount of space given to most students is 100 MB. That is not a lot of storage space! So, some effort must be made on your part not to exceed this disk quota. Every student with anUNIX account has a disk quota. This is the amount of space given to most students is 100 MB. That is not a lot of storage space! So, some effort must be made on your part not to exceed this disk quota. Everything that you store in your directory (/afs/umbc.edu/users/u/s/username/) counts towards this 100 MB limit. The exception is your backup directory. Everything that you store in your directory (/afs/umbc.edu/users/u/s/username/) counts towards this 100 MB limit. The exception is your backup directory. Exceeding your disk quota can cause any number of problems: Exceeding your disk quota can cause any number of problems: Failure to log in through a GUI Failure to log in through a GUI Inability to compile programs Inability to compile programs Abnormal application behavior Abnormal application behavior To check your usage and overall quota, type quota -v in a UNIX shell. If you are exceeding your quota, change your Web Browser settings so they cache less to disk. You may then have to manually delete the cached files. If you need help with this, see an OIT Help Desk consultant. To check your usage and overall quota, type quota -v in a UNIX shell. If you are exceeding your quota, change your Web Browser settings so they cache less to disk. You may then have to manually delete the cached files. If you need help with this, see an OIT Help Desk consultant. For more information on how to check your quota, see For more information on how to check your quota, see

Checking Your Quota Type in the quota -v UNIX command at the command line. Type in the quota -v UNIX command at the command line. Your output should look something like: Your output should look something like: Doin’ just fine. Doin’ just fine. Nearing the limit. Nearing the limit. Over the limit. Danger zone. Over the limit. Danger zone. solaris1[1]% quota –v Volume NameQuotaUsed%UsedPartition user.dhood %<<64%<<WARNING solaris1[1]% quota –v Volume NameQuotaUsed%Used Partition user.dhood %<< 64% <<WARNING solaris1[1]% quota –v Volume NameQuotaUsed%UsedPartition user.dhood % 64%

How to Get Back Under Quota OIT has made available a tool that goes through your account and tries to eliminate unnecessary files and very large files that may be putting you over the limit. OIT has made available a tool that goes through your account and tries to eliminate unnecessary files and very large files that may be putting you over the limit. You can issue the oitcleaner command... You can issue the oitcleaner command... Note: that the latter part of this script tries to remove larger files that are in your account. You have to answer "y" or "n" whether or not you want to remove these files. Note: that the latter part of this script tries to remove larger files that are in your account. You have to answer "y" or "n" whether or not you want to remove these files. You can also make sure that you have set up the web browser to cache as little as possible to disk. You can also make sure that you have set up the web browser to cache as little as possible to disk.

Restoring a Lost File Remember the backup directory only contains a copy of all of your files from the night before. Remember the backup directory only contains a copy of all of your files from the night before. If you need to restore a file that you deleted days ago, or just minutes ago (assuming minutes ago was still today), then you are not going to find the file here. If you need to restore a file that you deleted days ago, or just minutes ago (assuming minutes ago was still today), then you are not going to find the file here. If it is really important and it was in your account overnight for at least one of these backups, than you may be able to have OIT see if they can recover the file for you. If it is really important and it was in your account overnight for at least one of these backups, than you may be able to have OIT see if they can recover the file for you. Note that this is only done in the rarest and most dire circumstances. Note that this is only done in the rarest and most dire circumstances. In-class demo of recovering a file. In-class demo of recovering a file.

Remote login: SSH SSH stands for Secure SHell. SSH stands for Secure SHell. It provides terminal or shell access to some remote computer. It provides terminal or shell access to some remote computer. SSH can be simply thought as a secure version of telnet. SSH can be simply thought as a secure version of telnet. There are several SSH clients to choose from. Some are installed in the OIT labs, some you can install, and others require administrator privileges that you may not have under Windows (at least in the labs). There are several SSH clients to choose from. Some are installed in the OIT labs, some you can install, and others require administrator privileges that you may not have under Windows (at least in the labs). UNIX/Mac OS X - OpenSSH UNIX/Mac OS X - OpenSSH Windows - Tera Term Pro (available in the UMBC labs, not recommended for use) ‏ Windows - Tera Term Pro (available in the UMBC labs, not recommended for use) ‏ Windows – Putty (Recommended): Download from Windows – Putty (Recommended): Download from

Remote File Transfer: SCP SCP stands for Secure CoPy. SCP stands for Secure CoPy. SCP can be simply thought as a secure version of FTP. SCP can be simply thought as a secure version of FTP. Again there are many SCP clients out there: Again there are many SCP clients out there: WinSCP (available in the labs): WinSCP (available in the labs): The Linux command: The Linux command: scp localfile scp localfile

Open AFS AFS is a distributed file system, pioneered at Carnegie Mellon University and supported and developed as a product by Transarc Corporation (now IBM Pittsburgh Labs). It offers a client-server architecture for file sharing, providing location independence, scalability and transparent migration capabilities for data. AFS is a distributed file system, pioneered at Carnegie Mellon University and supported and developed as a product by Transarc Corporation (now IBM Pittsburgh Labs). It offers a client-server architecture for file sharing, providing location independence, scalability and transparent migration capabilities for data. IBM branched the source of the AFS product, and made a copy of the source available for community development and maintenance. They called the release OpenAFS. IBM branched the source of the AFS product, and made a copy of the source available for community development and maintenance. They called the release OpenAFS.OpenAFS Accessing the UMBC AFS Directory on a personal Windows computer: Accessing the UMBC AFS Directory on a personal Windows computer: Download and install the windows Open AFS client. During installation you will be prompted for an AFS cell name, you should enter umbc.edu Download and install the windows Open AFS client. During installation you will be prompted for an AFS cell name, you should enter umbc.edu When the installation is complete, you will need to reboot. After you reboot, there will be an icon that looks like a lock in the system tray. Click on this to launch the OpenAFS dialog. When the installation is complete, you will need to reboot. After you reboot, there will be an icon that looks like a lock in the system tray. Click on this to launch the OpenAFS dialog. Under the Tokens tab, click Obtain New Tokens... Under the Tokens tab, click Obtain New Tokens... Be sure that the cell name is umbc.edu and go ahead and enter your username and password, then press enter. If everything went ok, you should see an entry under tokens with your GL username. Be sure that the cell name is umbc.edu and go ahead and enter your username and password, then press enter. If everything went ok, you should see an entry under tokens with your GL username. Under the Drive Letters tab, click Add... Under the Drive Letters tab, click Add... Chose an unused drive letter, and enter the path to your root directory on GL (/afs/umbc.edu/users/u/s/username/), and click enter. If everything went ok, then you should see the drive letter added under the OpenAFS dialog. Chose an unused drive letter, and enter the path to your root directory on GL (/afs/umbc.edu/users/u/s/username/), and click enter. If everything went ok, then you should see the drive letter added under the OpenAFS dialog. You should now be able to browse the drive in Windows Explorer. You should now be able to browse the drive in Windows Explorer.