Unix for multiprocessor system, Computer Networking

UNIX For Multiprocessor System:-

The UNIX operating system for a multiprocessor system has a number of additional features as compared to the normal UNIX operating system.  Let us first talk about the design goals of the multiprocessor UNIX.  The original UNIX developed by Dennis Ritchie and Brian Kernighan was developed as general purpose, portable,time-sharing uniprocessor operating system.

The OS functions including virtual memory management, processor scheduling,I/O devices etc, are executed with a large amount of system software. Normally the size of the OS is larger than the size of the main memory.  The portion of OS that resides in the main memory is known as kernel. For a multiprocessor, OS is developed on three models viz: floating executive model, Master slave model, multithreaded kernel. These UNIX kernels are executed with locks semaphores and monitors.

Let us discuss these models in short.

1)  Master slave kernel: In this model, just one of the processors is designated as Master.

The master is responsible for the activities given below:

i) Running the kernel code

ii) Handling the system calls

iii) Handling the interrupts.

The rest of the processors in the method run only the user code and are known as slaves.

2)  Floating-Executive model: The master-slave kernel model is too restrictive in the sense that only one of the processors viz the designated master can run the kernel. This restriction may be relaxed by containing more than one processor capable of running the kernel and let additional capability by which the master may float between the various processors capable of running the kernel.

3)   Multi-threaded UNIX kernel: We know that threads are light-weight processors needs minimal state information comprising the processor state and contents of relevant registers. A thread being a (light weight) process is capable of implementing alone. In a multiprocessor system, more than one processor may implement simultaneously with each processor possibly implementing more than one threads, with the restriction that those threads which share resources must be allotted to single processor. Though, the threads which do not share resources may be allotted to dissimilar processors. In this model, in order to divide multiple threads requiring different sets of kernel resources spin locks or semaphores are used.

Posted Date: 3/4/2013 5:44:23 AM | Location : United States







Related Discussions:- Unix for multiprocessor system, Assignment Help, Ask Question on Unix for multiprocessor system, Get Answer, Expert's Help, Unix for multiprocessor system Discussions

Write discussion on Unix for multiprocessor system
Your posts are moderated
Related Questions
Q. Focus of Reliability Control? - Implementation of the OSI model puts emphasis on providing a reliable data transfer service while the TCP/IP model treats reliability as an e

Q. Illustrate TCP – bytes and segments? TCP - bytes & segments TCP at the sending site collects bytes into a packet called a segment TCP adds a header to each se


What is ARCNet? The  Attached  Resource Computer Network (ARCNet) standard was formed in 1977 at the Data Point Corporation by a scientist  -  John Murphy. ARCNet uses the toke

In this question, you will compare delays in packet switching (i.e. in IP networks), in circuit switching (i.e. in PSTN telephony) and in virtual circuit packet switching (i.e. in

Question 1 Brief the Fourth generation network. List its advantages and disadvantages Question 2 Explain the steps involved in component identification and call establishm

Sharing  information  To understand  how distance vector routing  works examine the  internet shown in  the  clouds represents local  area network . the  number  inside each c

Q. Illustrate about Sliding Window Protocols? - Sliding window - Keeps the unacknowledged outstanding frames in sender - Keeps the expected frames in receiver - Sequen

In a client's software , the structure of an Internet server's address keyed is as follows: Where: http refer for the communication protocol to be used www refer for th

Assuming that TCP Reno is used, consider the following diagram illustrating the behaviour of congestion window, and answer the questions below. a)  What was the value of sl