19-inch Industrial Frame
A 19-inch industrial frame (1U), generally called a 1U server is a case that contains the following structural format:
This type of frame can house a standard motherboard as well as one or several hard drives, IDEs, SCSIs and Serial ATAs. However, given that the case is not very thick, it is typically a good idea for the motherboard to include as many entry/exit peripherals as possible (video board, SCSI card, RAIDs, network card, etc.). In addition, the processor's fan and radiator have a particular shape so that they fit in the case. They generally carry the label "fan and radiator for 1U case".
It is, however, possible to add a PCI card by using a PCI Riser Card, i.e. an item that can be inserted in the PCI allowing you to add a PCI card to it.