SASOS project (1993-1996)

This project is no longer active; this page is no longer updated.

Related keywords: [security]

Summary

In this "SASOS" project we explored the potential for "single address-space operating systems". In the mid 1990s there was a lot of interest in operating systems that used a single, large address space, made possible by the new 64-bit microprocessors, to hold all processes and persistent data. Although the concept was interesting, it required an address to be used once and then never reused. We actually measured the usage of live computer systems to get a good estimate on how quickly such an address space would be consumed [kotz:jaddrtrace].

Related projects elsewhere

The following single-address-space operating system projects provided us with summaries of their work The following SASOS projects have their own WWW pages:

Download: mailing list

There was an electronic mailing list for people interested in such systems. The list is archived as a text file.

People

Preston Crow and David Kotz.

Funding and acknowledgements

This research was supported in part by US NASA Graduate Student Research Assistantship NGT-51160 and by Digital Equipment Corporation (DEC) through ERP contract number 2043.

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Papers tagged 'sasos'

[Also available in BibTeX]

Papers are listed in reverse-chronological order; click an entry to pop up the abstract. For full information and pdf, please click Details link. Follow updates with RSS.

1996:
David Kotz and Preston Crow. The Expected Lifetime of Single-Address-Space Operating Systems. Computing Systems. Summer 1996. [Details]

Trends toward shared-memory programming paradigms, large (64-bit) address spaces, and memory-mapped files have led some to propose the use of a single virtual-address space, shared by all processes and processors. To simplify address-space management, some have claimed that a 64-bit address space is sufficiently large that there is no need to ever re-use addresses. Unfortunately, there has been no data to either support or refute these claims, or to aid in the design of appropriate address-space management policies. In this paper, we present the results of extensive kernel-level tracing of the workstations on our campus, and discuss the implications for single-address-space operating systems. We found that single-address-space systems will probably not outgrow the available address space, but only if reasonable space-allocation policies are used, and only if the system can adapt as larger address spaces become available.

1994:
David Kotz and Preston Crow. The Expected Lifetime of “Single-Address-Space” Operating Systems. Proceedings of the ACM SIGMETRICS Conference on Measurement and Modeling of Computer Systems. May 1994. [Details]

Trends toward shared-memory programming paradigms, large (64-bit) address spaces, and memory-mapped files have led some to propose the use of a single virtual-address space, shared by all processes and processors. Typical proposals require the single address space to contain all process-private data, shared data, and stored files. To simplify management of an address space where stale pointers make it difficult to re-use addresses, some have claimed that a 64-bit address space is sufficiently large that there is no need to ever re-use addresses. Unfortunately, there has been no data to either support or refute these claims, or to aid in the design of appropriate address-space management policies. In this paper, we present the results of extensive kernel-level tracing of the workstations in our department, and discuss the implications for single-address-space operating systems. We found that single-address-space systems will not outgrow the available address space, but only if reasonable space-allocation policies are used, and only if the system can adapt as larger address spaces become available.

1993:
David Kotz and Preston Crow. The Expected Lifetime of “Single-Address-Space” Operating Systems. Technical Report, October 1993. Revised version appeared in SIGMETRICS ’94, and revised again on March 15, 1996. [Details]

Trends toward shared-memory programming paradigms, large (64-bit) address spaces, and memory-mapped files have led some to propose the use of a single virtual-address space, shared by all processes and processors. To simplify address-space management, some have claimed that a 64-bit address space is sufficiently large that there is no need to ever re-use addresses. Unfortunately, there has been no data to either support or refute these claims, or to aid in the design of appropriate address-space management policies. In this paper, we present the results of extensive kernel-level tracing of the workstations on our campus, and discuss the implications for single-address-space operating systems. We found that single-address-space systems will probably not outgrow the available address space, but only if reasonable space-allocation policies are used, and only if the system can adapt as larger address spaces become available.

[Kotz research]