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School of Computer Science & Engineering
University of New South Wales
Advanced Operating Systems
COMP9242 2002/S2
Next:
Single-Address-Space Operating Systems
Single-Address-Space Operating Systems
Address Spaces
Multiple address spaces:
How do processes share data?
Sharing between address spaces
Problems with sharing: Pointers!
Sharing across address spaces
Other problems with address spaces
Why do we have problems with sharing?
Single-Address-Space Operating Systems
SASOS characteristics:
Protection in a SASOS
Protection:
Single Address Space Advantages
Application View
SASOS Advantages: System View
SASOS Advantages: Hardware View
Single-Address-Space Operating Systems
IBM System/38
AS/400
Angel
Opal
Sombrero
Mungi
SASOS Issues
Mungi Security
Two basic kinds of mechanisms:
Discretionary Access Control in Mungi
Main Mungi abstractions:
Access validation:
Threads and protection domains
Protected Procedure Calls
Protection Domain Manipulation:
Discretionary Confinement in Mungi
Mandatory Access Control in Mungi
Mandatory access control operation
PDX again...
OS Extensibility
Existing approaches to OS extensibility (cont'd)
What's wrong?
What's needed?
Mungi Component Model
Extending extensions
Customisation
Overhead of mandatory access control
Extension system performance: Microbenchmarks
Extension system performance: Macrobenchmarks
Bibliography
About this document ...
Gernot Heiser 2002-10-24