I've read about the "hypervisor" in hardware virtualization. VMs are not my area, so I can't quite see where the term came from.

THe wikipedia article talks about how "the hardware's supervisor state was virtualized as well, allowing multiple operating systems to run concurrently in separate virtual machine contexts"

This implies that a supervisor process was virtualized.. which then probably originated a 'hyper'-visor. Is this true?

  • 1
    Probably someone in marketing.
    – Rocklan
    Apr 28, 2013 at 8:38
  • 1
    "hyper" is super in Greek. In very broad terms VMs have two modes, supervisor (full access to host's hardware) and user (restricted access). A VMM has supervisor access to several VMs (thus also to several hosts), therefore it's kind of a super-supervisor. Hypervisor sounds better ;)
    – yannis
    Apr 28, 2013 at 9:06

2 Answers 2



The term was in use at least as early as 1973, as seen in this advert from IPS Computer Marketing Corp. in Computerworld magazine (30 May 1973 - Vol. 7, No. 22):

360/651H or J System available for sale or lease Sept. 1973. Will supply with any number of selector channels. With 7074 Hypervisor.


It appears in these two 1970 papers, with one quoting the other.

Operating systems architecture, H Katzan Jr - Proceedings of the May 5-7, 1970, spring joint computer conference:

... Hypervisors are particularly useful when it is necessary to run an emulator and an operating system at the same time. Similar to multiprogramming systems, a hypervisor is characterized by: (1) limited access; (2) batch utilization; (3) high throughput performance; (4) priority ...

Analysis of Major Computer Operating Systems, CS McIntosh, KP Choate, WC Mittwede - 1970 - DTIC Document (PDF):

As a result, this classification scheme should not be viewed as conflicting with other schemes which attempt to either describe different system environments or that are used for other purposes. For example, Harry Katzan, Jr., in a report presented at the 1970 Spring Joint Computer Conference entitled "Operating Systems Architecture, " describes five operating system types: multiprogramming, hypervisor multiprogramming, time-sharing, virtual systems, and tri-level operating systems. This classification scheme was developed to encompass a number of experimental and research-oriented systems, including some of those cited above. Consequently, the classification structure does not purport to be an inclusive representation of commercially available software. Nevertheless, since several of these system types are not represented by any commercially available system, this categorization can only be superficially applied to the commercial environment.


It also appears in earlier snippets in Google Books, but care must be taken as Google often has incorrect metadata. However, this 1969 description of the IBM 360/60 in Management Services, (Volumes 6-7, American Institute of Certified Public Accountants) seems possible (date check):

To operate in the multiprograming mode with both control systems simultaneously would require a minimum of 128K bytes of core memory, and thus a 360/40, since maximum core for a 360/30 is 65K bytes of memory. In addition, a hypervisor (a master control system requiring both hardware and software) would be required to partition memory between both control systems.


It may also appear in a paper by IBM: A Virtual Machine System for the 360/40 (1966) by R Adair, R Bayles, L Comeau, R Creasy, but Google Books only shows it as a result and no text. If someone has access to this paper online, perhaps they can confirm it.

  • which journal was the 1966 paper? Apr 29, 2013 at 0:27
  • 1
    Here's a full citation: R. Adair, R. Bayles, L. Comeau, and R. Creasy. A virtual machine system for the 360/40. Technical Report 320-2007, IBM Corporation, Cambridge Scientific Center, May 1966.
    – Hugo
    Apr 29, 2013 at 6:07
  • The journal searches are really failing me now.... Apr 29, 2013 at 17:41
  • Not all IBM's technical reports are published in journals. I couldn't find it here -- domino.research.ibm.com/library/cyberdig.nsf/index.html -- but there's an email address.
    – Hugo
    Apr 29, 2013 at 18:19

"Hypervisor" goes back to the very beginnings of virtual machine systems: the CP/CMS projects at IBM's Cambridge Scientific Center, starting in 1964. The "CP" part was the hypervisor, which created virtual machines, while the "CMS" part was the OS that typically ran inside the vms. The oldest usage I'm aware of is in Goldberg & Popek's famous "Formal requirements for virtualizable third generation architectures" CACM paper from 1974. At the time, the only extant example of a VM hypervisor was CP-67, the version of CP that ran on IBM's System 360 Model 67.

  • Interestingly hypervisor is only mentioned as a keyword in Goldberg & Popek's paper, but it doesn't appear in the text itself (they use VMM instead). They do mention CP-67, so the term probably originated with it.
    – yannis
    Apr 28, 2013 at 12:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.