Transcript OPERATING SYSTEMS DESIGN AND IMPLEMENTATION Third

OPERATING SYSTEMS
DESIGN AND IMPLEMENTATION
Third Edition
ANDREW S. TANENBAUM
ALBERT S. WOODHULL
Yan hao (Wilson) Wu
[email protected]
University of the Western Cape
Computer Science Department
Minix Structure
From: Free Software Bazaar '06 2 Jorrit N. Herder
THE MINIX 3 USERMODE
SERVERS AND DRIVERS
Monolithic Kernel vs. Microkernel
Feature/Kernel type
Modularity
Flexibility
Maintainability
Security
Compatibility
Performance
Monolithic Kernel
Microkernel
Characteristics of Minix
● Minimal kernel to support user-mode OS
– Stable kernel (~4000 LoC) reduces number of fatal bugs
● User-mode modules are physically isolated by MMU
– Memory access must be explicitly granted by other party
● Privileges of each components are strongly restricted
– Policies for IPC, kernel calls, I/O, memory, scheduling
Minix Future
● Reliability and security become more
important!
– E.g., think of banking on embedded devices
● Starting to become useful operating system
– E.g., recently the X Window System was ported
● Open source project (under BSD license)
– You can inspect, modify, contribute, etc.
Resources for Minix
www.minix3.org
Towards a True Microkernel Operating System, Master's Thesis,
Vrije Universiteit, Amsterdam, The Netherlands, Feb. 2005.