The document discusses multiprocessor operating systems. It defines multiprocessors as systems with multiple processors that share components like memory and I/O devices. There are two types of multiprocessors: symmetric, where each processor has equal functionality and workload, and asymmetric, where one processor acts as the master. Multiprocessors provide benefits like increased performance but also introduce complexity in communication. They differ from multicomputers which have separate memory for each processor and can distribute work across independent systems.

1. Objectives
• Definition
• Multi processor operating systems
• Multiprocessor operating systems type
• Advantages of multiprocessor
• Disadvantages of multiprocessor
• Difference between multiprocessors and multicomputer

2. In General
Different processors speed up the framework, since various activities can be
performed all the while. Asymmetric multiprocessing is basic, just a single
processor (principal) can get to the information structure. While symmetric
multiprocessing is perplexing as the information structure is divided among all
processors and each processor needs to work in simultaneousness.

3. Definition
• Most computer systems are single processor systems i.e., they only have one
processor. However, multiprocessor or parallel systems are increasing in
importance nowadays. These systems have multiple processors working in parallel
that share the computer clock, memory, bus, peripheral devices etc. the main
objective of using a multiprocessor operating system is to increase the execution
speed of the system, more work done in less time (Brigh, 1965).
Figure 1 – Multiprocessing (Thakur, 2020)

4. Types of Multiprocessors
• There are two main types of processors, which are divided into symmetrical and
asymmetric types, and as explained below:
• Symmetric
By analogue, each processor has an operating system similar to the rest of
the processors. It works in parallel in a peer-to-peer relationship. An example of
this type of processor is Encore in the Unix kernel.
• Asymmetric
“ each processor is given a predefined task. There is a master processor that
gives instruction to all the other processors. Asymmetric multiprocessor system
contains a master slave relationship.” (Castro, 2020).

5. Types of Multiprocessors
Figure-2 (Difference Between Symmetric and
Asymmetric Multiprocessing 2019)

6. Main Difference
• In asymmetric processors, the tasks in the operating system are handled by the
main processor and the main processor distributes the tasks to the rest of the
processors, while in similar processors the tasks are run in the operating system.
• In symmetric multiprocessing, each processor has a queue of ready processes and
processes can be taken from a common queue to be processed.
• In multiple symmetric processors they have the same structure, but in asymmetric
processors the structure of the processors is different.

7. Main Difference
• Symmetric processors communicate with each other through shared memory, and
in multiple asymmetric processors, they do not need to communicate with each
other, as they are controlled by the main processor.
• In the event of failure of the coprocessor in asymmetric processors, the processing
is transferred to the main processor, but in symmetric processors in case of failure,
the computing power of the system is reduced

8. Advantages of Multiprocessor
• High productivity
• Less electricity consumption
• High reliability
• Low cost to work

9. Disadvantages of Multiprocessor
• The complexity of communication architecture
( O.S it take care more processor In same time )
• Big Memory
• Deadlock
• Time Consuming in case of failure

10. Multiprocessors vs. Multicomputer
Multiprocessor
• Multiprocessor is simply computer that has more than one cpu up on its motherboard .
• Multiprocessing is the use of two or more central processing units cpu with single computer
systems .
• Multiprocessor have single physical address space memory shared by all the cpus
• Multiprocessor would run slower because it would be in one computer .
• Multiprocessor is single system with multiple cpu (Wolf, 2004).

11. Multiprocessors vs. Multicomputer
• Multicomputer
• A computer made up of several computers . Similar to parallel computing .
• Distributed computing deals with hardware and software systems containing more than one processing
element multiple programs running under loosely or tightly controlled regime .
• Multicomputer have one physical address space per cpu .
• It can run faster
• Is multiple computers each of which can have multiple processor used for true parallel processing
• A concept known as distributed fault-tolerance is introduced. A model of a large multiprocessor system is
developed and techniques, based on this model, are given by which each processing element can correctly
diagnose failures in all other processing elements in the system (Wolf, 2004).

12. References
• Brigh, H. S. (1965). A Philco multiprocessing system. Proceedings of the October 27-29, 1964, Fall Joint
Computer Conference, Part II: Very High Speed Computer Systems on XX - AFIPS ’64 (Fall, Part II).
https://doi.org/10.1145/1464039.1464051
• Thakur, D. (2020, August 10). Definition Multiprocessor Operating System. Computer Notes. Retrieved
September 22, 2022, from https://ecomputernotes.com/fundamental/disk-operating-
system/multiprocessor-operating-system
• Castro, K. (2020, June 21). Multiprocessor Systems. Tutorials Point. Retrieved September 24, 2022, from
https://www.tutorialspoint.com/Multiprocessor-Systems#
• Difference Between Symmetric and Asymmetric Multiprocessing (with Comparison Chart). (2019,
December 26). Tech Differences. Retrieved September 24, 2022, from
https://techdifferences.com/difference-between-symmetric-and-asymmetric-multiprocessing.html
• Rehman, J. (2021, November 4). Advantages and disadvantages of multiprocessor systems. IT Release.
Retrieved September 24, 2022, from https://www.itrelease.com/2020/06/advantages-and-disadvantages-
of-multiprocessor-systems/
• Wolf, W. (2004). The future of multiprocessor systems-on-chips. Proceedings of the 41st Annual
Conference on Design Automation - DAC ’04. https://doi.org/10.1145/996566.996753