VM/386 is a multitasking operating system or 'control program'[1] that took early advantage of the capabilities of Intel's 386 processor. By utilizing Virtual 8086 mode, users were able to run their existing text-based and graphical DOS software in safely separate environments.[2] The system offered a high degree of control, with the ability to set memory and CPU usage limits. Unique CONFIG.SYS and AUTOEXEC.BAT files could be configured for each application, and even different DOS versions.[3]
VM/386 had initially been developed by Softguard Systems, a producer of copy-protection software, with plans to include features like non-DOS system support,[4] but financial constraints forced its sale to Intelligent Graphics Corporation, which launched the product in 1987.[5] It won a PC Magazine award for technical excellence in 1988.[6] The company also introduced a multi-user version, which allowed a number of serial terminals and even graphical systems to be connected to a single 386 computer.[7] Current versions of the software have built on the multi-user support, and can handle tens of users in a networked environment with Windows 3.11 support, access controls, virtual memory and device sharing, among other features. [8]
A version of the software designed to cooperate with Unix was bundled with Everex Systems workstations.[9] The system now sees use mainly in vertical applications like point-of-sale systems, where its ability to run reliably on cheap, reliable hardware outweigh any gains from newer operating systems that are more complex and less reliable.[10]
Early competition included Desqview 386, Sunny Hill Software's Omniview, and Windows/386 2.1.[3] As the target market shifted away from single-user systems to multiple-user setups with many serial terminals it began to compete more directly with the likes of Multiuser DOS and PC-MOS/386.