CoolInterview.com - World's Largest Collection of Interview Questions & Answers, FAQs, queries, sample papers, exam papers, dumps, what, why, how, where, when questions
Our Services
Get 9,000 Interview Questions & Answers in an eBook.




Get it now !!
Send your Resume to 6000 Companies

Search Interview Questions

Question: Describe the Buddy system of memory allocation

Answer: Free memory is maintained in linked lists, each of equal sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.



Category Operating Systems Interview Questions & Answers - Exam Mode / Learning Mode
Rating (0.5) By 486 users
Added on 9/9/2014
Views 4436
Rate it!
Question: Describe the Buddy system of memory allocation
Answer:

Free memory is maintained in linked lists, each of equal sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list. Source: CoolInterview.com


The buddy memory allocation technique is a memory allocation algorithm that divides memory into partitions to try to satisfy a memory request as suitably as possible. This system makes use of splitting memory into halves to try to give a best-fit

The buddy memory allocation technique allocates memory in powers of 2, i.e 2x, where x is an integer. Thus, the programmer has to decide on, or to write code to obtain, the upper limit of x. For instance, if the system had 2000K of physical memory, the upper limit on x would be 10, since 210 (1024K) is the biggest allocatable block. This results in making it impossible to allocate everything in a single chunk; the remaining 976K of memory would have to be taken in smaller blocks. Source: CoolInterview.com

Answered by: Surendra Verma (MTech), Delhi | Date: 6/2/2010 | Contact Surendra Verma (MTech), Delhi Contact Surendra Verma (MTech), Delhi


If you have the better answer, then send it to us. We will display your answer after the approval

Rules to Post Answers in CoolInterview.com:-

  • There should not be any Spelling Mistakes.
  • There should not be any Gramatical Errors.
  • Answers must not contain any bad words.
  • Answers should not be the repeat of same answer, already approved.
  • Answer should be complete in itself.

Post your answer here

Inform me about updated answers to this question.
Related Questions
View Answer
Define latency, transfer and seek time with respect to disk I/O
View Answer
What are local and global page replacements?
View Answer
What is a trap and trapdoor?
View Answer
When does the condition 'rendezvous' arise?
View Answer
Explain the popular multiprocessor thread-scheduling strategies
View Answer
What is busy waiting?
View Answer
What are the stipulations of C2 level security?
View Answer
What is meant by arm-stickiness?
View Answer
What is cycle stealing?
View Answer
When is a system in safe state?
View Answer
What is the resident set and working set of a process?
View Answer
What is the Translation Lookaside Buffer (TLB)?
View Answer
What are the typical elements of a process image?
View Answer
What are turnaround time and response time?
View Answer
What are short-, long- and medium-term scheduling?
View Answer
List the Coffman's conditions that lead to a deadlock.
View Answer
What is thrashing?
View Answer
What is a binary semaphore? What is its use?
View Answer
Explain Belady's Anomaly.
View Answer
Explain the concept of Reentrancy.
View Answer

Please Note: We keep on updating better answers to this site. In case you are looking for Jobs, Pls Click Here Vyoms.com - Best Freshers & Experienced Jobs Website.

View All Operating Systems Interview Questions & Answers - Exam Mode / Learning Mode




India News Network
Latest 20 Questions
Payment of time- barred debt is: (a) Valid (b) Void (c) Illegal (d) Voidable
Consideration is defined in the Indian Contract Act,1872 in: (a) Section 2(f) (b) Section 2(e) (c) Section 2(g) (d) Section 2(d)
Which of the following is not an exception to the rule, "No consideration, No contract": (a) Natural love and affection (b) Compensation for involuntary services (c) Completed gift (d) Agency
Consideration must move at the desire of: (a) The promisor (b) The promisee (c) The promisor or any other party (d) Both the promisor and the promisee
An offer which is open for acceptance over a period of time is: (a) Cross Offer (b) Counter Offer (c) Standing Offer (d) Implied Offer
Specific offer can be communicated to__________ (a) All the parties of contract (b) General public in universe (c) Specific person (d) None of the above
_________ amounts to rejection of the original offer. (a) Cross offer (b) Special offer (c) Standing offer (d) Counter offer
A advertises to sell his old car by advertising in a newspaper. This offer is caleed: (a) General Offer (b) Special Offer (c) Continuing Offer (d) None of the above
In case a counter offer is made, the original offer stands: (a) Rejected (b) Accepted automatically (c) Accepted subject to certain modifications and variations (d) None of the above
In case of unenforceable contract having some technical defect, parties (a) Can sue upon it (b) Cannot sue upon it (c) Should consider it to be illegal (d) None of the above
If entire specified goods is perished before entering into contract of sale, the contract is (a) Valid (b) Void (c) Voidable (d) Cancelled
______________ contracts are also caled contracts with executed consideration. (a) Unilateral (b) Completed (c) Bilateral (d) Executory
A offers B to supply books @ Rs 100 each but B accepts the same with condition of 10% discount. This is a case of (a) Counter Offer (b) Cross Offer (c) Specific Offer (d) General Offer
_____________ is a game of chance. (a) Conditional Contract (b) Contingent Contract (c) Wagering Contract (d) Quasi Contract
There is no binding contract in case of _______ as one's offer cannot be constructed as acceptance (a) Cross Offer (b) Standing Offer (c) Counter Offer (d) Special Offer
An offer is made with an intention to have negotiation from other party. This type of offer is: (a) Invitation to offer (b) Valid offer (c) Voidable (d) None of the above
When an offer is made to the world at large, it is ____________ offer. (a) Counter (b) Special (c) General (d) None of the above
Implied contract even if not in writing or express words is perfectly _______________ if all the conditions are satisfied:- (a) Void (b) Voidable (c) Valid (d) Illegal
A specific offer can be accepted by ___________. (a) Any person (b) Any friend to offeror (c) The person to whom it is made (d) Any friend of offeree
An agreement toput a fire on a person's car is a ______: (a) Legal (b) Voidable (c) Valid (d) Illegal
Cache = 0.03125 Seconds