Interactive use of the PPPL cluster

There are two types of interactive use on the cluster, non-exclusive and exclusive.

For non-exclusive use, ssh to This is an alias for several systems where logins are allocated to the systems in a least loaded fashion. You use portal as you would any timesharing system, and you will be one of many users on the system. So it is important to not run very high CPU or memory intensive processes on portal. Instead, reserve a set of systems for your exclusive use as detailed in the next section.

(The portal set of systems runs a 64 bit kernel. You can run 32 or 64 bit executables on this kernel).

For exclusive use of a system or systems, ssh to portal and execute the command use. This command will ask you a few questions about the number and types of hosts you wish to use, then allocates those hosts for your exclusive use from a pool of systems reserved for this type of use. No other users will be allowed onto those hosts. This provides you with uninterrupted and non-contentious use of the hosts.

By default, the use command allocates the system to you for 16 hours. To override this, type use -w hh:mm, for example use -w 24:00 to use the system exclusively for 24 hours.

Your exclusive interactive request is queued and scheduled just like any other job, but when executed, the standard input, output, and error streams of the job are connected through your terminal session.