Each graduate office typically has at least one general purpose CSLab machine. While these machines may not restrict logins locally or remotely, it is expected that you seek the permission of the people whose office the machine is in before using it.
Research Labs
Many faculty maintain labs for use with their research projects. Machines in these labs are typically to be used only by members of the appropriate faculty member's research group.
Remote access
linux.cs.rpi.edu is for general purpose remote access
Other Resources
Resources in the CCI may be available to people doing parallel computing