Computing Environment

Table of Contents

• Computers
• Accounts
• Disk management and directories
• File Permissions
• Remote Connections
• Printing
• Connecting your laptop

• In a separate document...

• Data back-up

Computers at the beam lines

The naming convention of computers described below are for bl9-2. The pattern is the same for all crystallography beam lines. Replace '92' with '15', '71', '91', '111' '113' and '122' for beam lines 1-5, 7-1, 9-1, 11-1, 11-3 and 12-2, respectively.

bl92[a,b,c]: data collection, backup and graphics (Linux Workstation)

blcpu[1,2,3,4,5]: data processing (Compaq/HP AlphaServer ES40/45/80 with four or eight CPUs each)

blcpu1L: data processing (Itanium 2-based sever with 16 CPUs running Linux)

blcpu[3,4,5,1L]: reserved for on-line users that are currently collecting data.

blcpu[1,2]: available to on-line and off-line users. See the off-line computer use policy.

smbcopy: dedicated host for file transfers. Is on a gigabit network link. Use this host to avoid having file transfers affect data processing.

bl92hutch: A terminal located inside the hutch for running the beamline control software.

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Accounts

A personal Unix account is required to log in to the beamline computers, data processing computers and web applications. Follow the instructions to request and maintain a computer account. Contact Thomas Eriksson for additional questions about accounts.

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Disk management and directories

Home directories are mounted as /home/accountname.

This directory is used for files that need to be stored indefinitly. All other directories are deleted on a regular basis. Users are responsible for backing up all data before leaving SSRL.

Data images should be saved in the directory /data/accountname. Diffraction images must not be stored in the /home area.

At login the following directories are created unless they already exist:

/home/accountname/www
/data/accountname
/data/accountname/templates

The 'www' subdirectory can be used to make information available through HTTP (web browser). It can be accessed via the URL:

Copies of the default data processing template files are stored in the 'templates' subdirectory.

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File Permissions

The default file permission restricts anyone else from listing, reading and writing files in your home and data directories. Files located in your 'www' directory are readable by everyone.

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Remote Connections

Only secure connections to SSRL are allowed, telnet and ftp are disabled.

To connect between SSRL computers use:

(Passwords are not required for internal connections)

To connect to a remote computer use the following command:

See the Remote File Transfer section in the backup documentation for further information.

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Printing

A printer is available at each beam line. The beamline computers will print to the local printer by default.

The blcpu (Alpha) computers prints to a printer in Trailer 274 by default. To set a private default printer, find the name of your preferred printer in table above, then use the command:

Alternatively, you can set the environment variable LPDEST to one of the printer names, and the lp command will use that as the default printer destination.

Print to default printer:

lp filename

Print to a named printer:

lp -dprintername filename

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Connecting a laptop to the local network

The SLAC visitor network is available at all SSRL macromolecular crystallography beamlines. The SLAC visitor network is a SLAC owned network which is outside the SLAC network firewall. Access to SSRL computers through the SLAC visitor network are treated as external connections.

Access to the SLAC visitor network at the beamlines is available via a wireless LAN and a standard wired network. Red network cables at the beamlines indicate that they are configured for the visitor network. Both wireless and cable connections require configuring the network interface on laptop computers to use DHCP (Dynamic Host Configuration Protocol) to obtain a valid network address. DHCP is the only way that laptops and computers can connect to the visitor network. Users are responsible for all network configuration and other equipment required for access (i.e. network card or wirless network card). SLAC's website provides information about how to configure your laptop for DHCP and wireless networking and the wireless PC card.

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