MIPS SPARC Alpha UNIX HP DEC Sun Microsystems Silicon Graphics (SGI) NeXT IBM workstation operating system Workstations PCs
Prior to around the year 2000, it was common for workstations to be based around a unique bespoke architecture and the machines would be quite distinctive relative to PCs typically seen in business or the home. It was not uncommon for workstation vendors to produce their own CPUs with architectures such as MIPS, SPARC and Alpha appearing. Workstations often had custom-built graphics processors to achieve higher resolutions and colour depth than was typical on IBM PC machines of the era. Vendors would usually offer a proprietary operating system as standard, this was most often a variant of UNIX which afforded some degree of compatibility between competing workstation vendors but less so with software for DOS or Windows based IBM PCs. Vendors that were noted for the production of workstations included HP, DEC, Sun Microsystems, Silicon Graphics (SGI) and NeXT. 
