This model was a disk storage server used in the Data Centre up until 2012. Each tray contains a hard disk drive (see the 5TB hard disk drive on the main disk display section - this actually fits into one of the trays). There are 16 trays in all per server. There are hundreds of these servers mounted on racks in the Data Centre, as can be seen.

The DEC (Digital Equipment Corporation) VT220 is a text terminal which uses an redesigned keyboard(LK201). The VT220 improved on the earlier VT100 series of terminals with much smaller physical packaging and and a much faster microprocessor.

The CERN computer centre has hundreds of racks like these. They are over a million times more powerful than our first computer in the 1960's. This tray is a 'dual-core' server. This means it effectively has two CPUs in it (eg. two of your home computers minimised to fit into a single box). Also note the copper cooling fins, to help dissipate the heat.