2. Mach Kernel

2. Mach Kernel
	Chapter 7. Parallel Machines

Mach Main Abstractions
1. Processes
2. Threads
3. Memory Objects
4. Ports
5. Messages
Unix Servers
- Resource Management (Kernel).
- Handler for system calls (Server).
Advantages:
1. OS becomes simpler.
2. OS becomes more machine independent.
3. Multiple OSs can run at the same time.

Processes
- Address Space
- Threads
  Figure 7.3. Mach Processes
  Bootstrap port - initialization
  Exception port - report errors to processes
  Registered port - communication with standard server (like DNS)
  Process port - process related information
Threads
- Thread port
- Commands FORK, EXIT, JOIN, DETACH, YIELD, SELF
- Scheduling done by the kernel.
Memory Management
- Virtual Memory
  Figure 7.4. Mach Virtual Memory
- Memory Sharing
  Figure 7.5. Meteorological/Agricultural Environmental
- External Memory Manager
  external pager

Communication
- Ports
  Figure 7.6. Ports
- UNIX Emulation Mach
  Figure 7.7. Unix Emulation


1. Introduction		3. Windows 3.1 & Windows 95