Describe two segment-replacement algorithms, Operating System

Assignment Help:

Q. Segmentation is alike to paging but uses variable-sized "pages". Describe two segment-replacement algorithms based on FIFO and LRU page replacement schemes. Remember that since segments aren't the same size the segment that is chosen to be replaced mayn't be big enough to leave enough consecutive locations for the needed segment. Consider tactics for systems where segments cannot be relocated and those for systems where they can.

Answer:

a. FIFO. Find the first segment large sufficient to accommodate the incoming segment. If relocation isn't possible and no one segment is large enough select a combination of segments whose memories are contiguous which are closest to the first of the list and which are able to accommodate the new segment. If relocation is probable rearrange the memory so that the first N segments large sufficient for the incoming segment are contiguous in memory. Add any leftover space to the free-space list in both cases.

b. LRU. Select the segment that hasn't been used for the longest period of time and that is large enough adding any leftover space to the free space list. If no one segment is large sufficient select a combination of the oldest segments that are contiguous in memory (if relocation isn't available) as well as that are large enough.

If relocation is obtainable rearrange the oldest N segments to be contiguous in memory as well as replace those with the new segment.


Related Discussions:- Describe two segment-replacement algorithms

Define the os/2 threads code, Define the OS/2 threads code The sample p...

Define the OS/2 threads code The sample program in Listing is very similar to the NetWare example. OS/2 commands are substituted for the pseudocode commands controlling thread

Write xeyes on command line, Ask question #Minimum 100 words accepteWrite a...

Ask question #Minimum 100 words accepteWrite an xeyes command to display a window that is: ? SIZE: ¦ 400 pixels wide ¦ 300 pixels tall ? LOCATION: ¦ 100 pixels from the right edge

Comparing gc to malloc, Garbage collectors trade space for time. If we coll...

Garbage collectors trade space for time. If we collect all the time (which requires a lot of processing time), the GC allocator will use the least memory possible. On the other han

What is super block, What is super block A partition control block have...

What is super block A partition control block have partitions details, such as the number of blocks in the partition, size of the blocks, free-blocks and free-block pointers an

Explain the alphabet and string, Explain the Alphabet and String A fini...

Explain the Alphabet and String A finite set of symbols is known as alphabet. An alphabet is frequently denoted by sigma, yet can be given any name. B = {0, 1} says B is an

What are the requirements for a swapper to work, The swapper work s on t...

The swapper work s on the biggest scheduling priority. Initially it will look for any sleeping process, if not get then it will see for the ready-to-run process for swapping. Bu

Define properties to ensure good search performance, Define Properties to E...

Define Properties to Ensure Good Search Performance A hashing function h should possess the subsequent properties to make sure good search performance: a. The hashing functi

What are the benefits of thread pools, What are the benefits of thread pool...

What are the benefits of thread pools:- The benefits of thread pools are 1. It is usually faster to service a request with an existing thread than waiting to make a thread.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd