its maintenance obligations to another company, thus being able to concentrate on the CAD/CAM software business. The company was renamed from Prime Computervision to Computervision (CV). Hardware Computervision created a GPU, Graphics Processing Unit, in 1980. It could traverse and render hierarchical display lists. It also produced a DCU, Display Control Unit, in 1983 with a large color raster display and attached rendering engine for basic UI operations. In 1985, CV introduced an IBM 4361-based mainframe known as the CDS5000 to support Product Data Manager (PDM). This system never ran any graphics software but instead was used to manage the large number of product files and data that users were generating. The CDS5000 was networked with CDS4000 and CGP200X systems using serial links. PDM was later made platform independent and was offered on the original IBM platform, as well as DEC/VMS and Sun/Unix - opening up its CADDS workstations to run in conjunction with this range of host platforms for product data vaulting, access/security, revision control, backup/recovery, archive/restore features. Computervision was crucial to Sun Microsystems development as a company. CV was Sun's first large customer for Unix-based workstations. The CDS3000 series of workstations were actually Sun-2 systems with additional graphics hardware from CV. Ultimately in 1987, CV migrated from the CGP systems to Sun-3-based workstations known as CADDStations with a VME bus version of the GPU. Computervision merged with Prime Computer in 1988 and acquired GE Calma (its major competitor in the microelectronic CAD market) in 1989. Computervision was acquired by Parametric Technology Corporation (PTC) in 1998, which (as of 2013) still produces the CADDS5 product, although only as a CAD/CAM product specialized for shipbuilding. In 2001, PTC sold the MEDUSA and MPDS Plant Design System software rights to CAD Schroer, which has developed a Fourth Generation of each system. Customers One of the first major customers in the UK for ComputerVision were the construction company John Laing PLC. "In 1975 John Laing purchased a ComputerVision CADDS3 computer aided design and drafting system to carry out investigations into the use of CAD in the construction engineering and building environment" - Mervyn Richards, Laing Technology Group (Thomas Telford Press, Institute of Civil Engineers, Conference - ) Laing Design Partners, a division of John Laing, had for some time been sponsoring work at Imperial University on the use of CAD in construction in the early 1970s and this led to Laing choosing