IBM M44/44X
| Company type | Research project |
|---|---|
| Industry | Computer hardware, Virtualization |
| Founded | 1960 |
| Headquarters | Yorktown Heights, New York , United States |
Key people | Dave Sayre, Rob Nelson |
| Parent | IBM Thomas J. Watson Research Center |
The IBM M44/44X represented a groundbreaking computer system from the mid-1960s, engineered at IBM's Thomas J. Watson Research Center located in Yorktown Heights, New York. This system was constructed around a customized IBM 7044 model (referred to as the 'M44'), which enabled the simulation of several 7044 virtual machines (designated as '44X') by integrating both hardware and software components. Among the principal contributors were Dave Sayre and Rob Nelson. This innovative platform served as a testbed for investigating paging, the concept of virtual machines, and methods for computer performance measurement. In 1981, Peter Denning acknowledged it as a quintessential example of experimental computer science.
The phrase virtual machine is believed to have originated with the M44/44X initiative and was subsequently adopted by the CP-40 development team as a replacement for their prior term pseudo machine.
In contrast to the CP-40 and subsequent CP/CMS control programs, M44/44X did not provide complete emulation of the underlying hardware (full virtualization). Robert Creasy, leader of the CP-40 project, remarked:
The M44/44X "was about as much of a virtual machine system as CTSS – meaning it was sufficiently close to demonstrate that 'close enough' was insufficient. I have never encountered a more compelling endorsement for virtual machines than from Dave Sayre."
The M44/44X project illustrated that virtual machine technology could achieve efficiency on par with traditional methods—a fundamental premise within the CP/CMS architecture that later attained significant success.
References
- R. J. Creasy, "The origin of the VM/370 time-sharing system," IBM Journal of Research & Development, Vol. 25, No. 5 (September 1981), pp. 483-490 – an overview on CP/CMS and VM history by the leader of the CP-40 project
- Peter J. Denning, "Performance Modeling: Experimental Computer Science at its Best," Communications of the ACM, President's Letter (November 1981) – an influential review highlighting key M44/44X research on paging and virtual memory
- R. W. O'Neill, "Experience using a time sharing multiprogramming system with dynamic address relocation hardware," Proc. AFIPS Computer Conference 30 (1967), pp. 611–621 – discusses M44/44X performance and its effects on multiprogramming
- R. A. Nelson, "Mapping Devices and the M44 Data Processing System," IBM Thomas J. Watson Research Center (1964) – technical details regarding the M44/44X system architecture
- D. Sayre, On Virtual Systems, IBM Thomas J. Watson Research Center (1966) – an early publication on multiprogramming concepts implemented in M44/44X
- Melinda Varian, VM and the VM community, past present, and future, SHARE 89 Sessions 9059-9061 (1997) – a thorough resource covering CP/CMS and VM historical development
Citations