What are the "standard linux workstations" systems?

Documentation and computing-news blog entries often refer to the standard linux workstations or ms workstations. This refers to the Dell GX270 linux workstations used by graduate-students, post-doctoral fellows and some faculty members. The grad student and post doc workstations are named for their location (e.g. ms-hh-303-04 for the Math & Stats workstation at desk 4 in HH-303).