outgrowth of RSX-15. The XVM'' upgrade to RSX was multi-user, and enabled up to six concurrent teletype-based users. XVM Support for the PDP-15/76 included using an RK05 disk drive. non-DEC One other operating system, developed on the PDP-7, was also available for the PDP-15: MUMPS, which was originally developed in 1966 Application software DEC provided mathematical, scientific and commercial software application tools. See also Programmed Data Processor References External links a diary re PDP-15 & RSX-15 DEC minicomputers 18-bit computers Transistorized computers Computer-related introductions in 1970