VPS/VM
| Company type | Operating system |
|---|---|
| Industry | Computer software |
| Founded | 1977 |
| Founder | Charles Brown, John H. Porter |
| Defunct | circa 1993 |
| Headquarters | Boston , United States |
| Products | Operating system for IBM System/370 and IBM 3090 mainframes |
VPS/VM (Virtual Processing System/Virtual Machine) was an operating system utilized on IBM System/370 through IBM 3090 machines at Boston University from 1977 until approximately 1990, with sporadic usage continuing until at least 1993. Throughout the 1980s, VPS/VM served as Boston University's main operating system, accommodating up to 250 concurrent users—substantially exceeding the capacity of competing VM/CMS systems, which supported about 120 simultaneous users.
Users worked within individual Virtual Machines managed by VM, IBM’s hypervisor operating system. VM supplied the virtual IBM 370 environment hosting VPS instances. The VM software was altered to enable VPS virtual machines to share memory pages with both read and write privileges. VPS incorporated a shared nucleus and memory pages to facilitate data exchange between VMs, mirroring MVS design principles but replacing Address Spaces with Virtual Machines.
Origins
Craig Estey, who was part of Boston University’s Academic Computing Center between 1974 and 1977, described:
Description
VPS/VM was an IBM-based OS resembling certain DOS/VSE time-sharing systems, offering users an IBM 3270 full-screen terminal interface (green screen) similar to VM/CMS. Each user operated within an 11 MB virtual machine (including a 3 MB memory gap) and, starting in 1984, could execute multiple applications simultaneously.
The system was initially created by Charles Brown, a doctoral candidate at BU, alongside John H. Porter, a physics PhD who later managed the VPS project and became Boston University’s vice president for information systems. Marian Moore authored much of the subsequent VM code. Josie Bondoc contributed enhancements such as UNIX-style piping.
VPS/VM supported a variety of MVS/VM-compatible applications including XEDIT, as well as compilers for Pascal, PL/1, C, and Cobol. These programs operated within an OS simulation layer that emulated OS/VM supervisor calls (SVCs), developed under the leadership of Margorie Orr with assistance from Timothy Greiser, Daniel Levbre, John Coldwell Lotz, and Paul Cheffers.
Early utilities like IFMSG, the VPS-specific JCL, and MAIL (an initial email client) were created by Michael Krugman. Francis Costanzo developed SENDMAIL to enable email communication over the BITNET network.
Before SQL databases became common, tools such as FOCUS and NOMAD2 were deployed on VPS. Michael Gettes also designed an early HELP system.
The file system began as non-hierarchical with unique filenames limited to eight characters but later evolved to provide personal directories for users. VPS supported tape storage, IBM disk files, and native VPS text file formats.
A basic shell was available without pattern matching capabilities except through the PAW program developed by Paul Cheffers. During the mid-1980s, Glenn Bresnahan’s graphics group ported most UNIX utilities onto the system.
William Marshall authored much of the foundational documentation and provided PL/1 programming support. Joe Dempty led User Services while Diana Robanske and John Houlihan acted as statistics consultants assisting student users from 1980 through 1985.
As a practical pre-GUI IBM operating system, VPS/VM managed a greater user load than many IBM TSO environments. Unlike typical academic systems that offered only basic editors and compilers, VPS served more than 10,000 Boston University users over more than ten years.
The decision to develop the OS and core utilities in IBM 370 assembler language constrained its growth and competitiveness against emerging UNIX-based platforms that eventually supplanted it. Nevertheless, VPS influenced many features found in contemporary operating systems globally and provided extensive training for IBM370 assembler programmers throughout the 1980s.
See also
References
- Paul Cheffers, the initial creator, played a role in advancing the VPS/VM operating system between 1981 and 1985.