1. B.Ramamurthy Chapter 2 : Appendix
Windows NT and Unix OS
B.Ramamurthy
Chapter 2 : Appendix
1/10/2019
B.Ramamurthy

2. Windows NT
Significance: Designed from scratch incorporating all the latest technologies available at that time.
Single user, multi-tasking
Client-server
SMP : Symmetric multiprocessing
Multi-threading
Micro-kernel approach
Object-oriented design
Graphical User Interface (Windows)
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B.Ramamurthy

3. Windows NT Architecture Fig.2.13
NT can execute on a variety of hardware platform:
Posix, Win32, OS/2, etc.
NT separates the application-oriented software from OS software by an elaborate module known as NT Executive.
NT execution operates in the kernel mode.
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B.Ramamurthy

4. NT Executive Highly modular, modified micro-kernel.
Well-defined API for each module allows easy modification of functionality.
Hardware Abstraction Layer (HAL): maps between command s and hardware. DMA, Interrupt controller, SMP are supported at this layer.
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5. MicroKernel
Microkernel consists of most fundamental components of the operating system.
Process control, thread control, context switching, scheduling, synchronization etc.
Non pre-emptable.
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6. Services Executive Services:
IO manager, and Window Manager which directly deal with harwdare.
Object manager, Security, process, virtual memory, call manager: these modules go thru’ HAL.
System Services: interface to user-mode software.
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7. Object-Oriented Approach
NT is partially OO.
Processes, files, threads, semaphores, timers, windows are all designed as objects (classes).
Each object created has a handle (object reference) and a security descriptor (SD).
Many other data structures used are not classes or objects.
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B.Ramamurthy

8. Traditional Unix System Fig.2.16
System call interface
File Subsystem
Process Control subsystem
Device driver/ IO subsystem
Hardware control
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9. Modern Unix Kernel System V release 4 (SVr4) Solaris 2.x
Berkeley Software Distribution (BSD 4.4)
Core facilities, + set of specific functionalities (scheduler, vnode interface, Virtual memory management, etc.)
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10. OS Topics Fig2.18 Memory Management File Management
Process Description and Control
IO management
Security
Networking
Concurrency
Scheduling
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B.Ramamurthy