1 votes 1 votes Consider linked allocation system, a program has just read the 15th disk block. After some point of time, If it next want to use the 20th block, then how many disk blocks must the program access? a: 5 b: 10 c:15 d:20 Operating System made-easy-test-series operating-system disk + – rahul sharma 5 asked Dec 18, 2017 • edited Mar 7, 2019 by Aditi Singh rahul sharma 5 1.2k views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments rahul sharma 5 commented Dec 20, 2017 reply Follow Share @VS:- The key point here is after some point of time, So we don't know after some point of time whether we are at 15 or some other.And in that case we will take the worst case.We will start from 1 block and access 20 blocks. I questions says,we are and now from 15 we need to access 20th block,then 5 will be correct 2 votes 2 votes VS commented Dec 20, 2017 reply Follow Share @rahul sharma 5 But, once we reached 15 th block why can't we store the addr of 15th block in a separate variable and then use it latter on ! 0 votes 0 votes rahul sharma 5 commented Dec 21, 2017 reply Follow Share @VS:- May be some insertion deletion done and that 15 block address is not a valid address now.Assume you are at 10 th node at linked list.Now after some time you need to goto 15th node.You dont know where you are after some one.Begining or and or middle(anywhere).Even if you save 10th node address earlier,then whether it is valid now or not,we dont know. 1 votes 1 votes Please log in or register to add a comment.
0 votes 0 votes Linked List Allocation In this scheme, each file is a linked list of disk blocks which need not be contiguous. The disk blocks can be scattered anywhere on the disk. Therefore we need 20 Block Access In Worst Case Himanshu Kumar Gupta answered Jun 24, 2020 Himanshu Kumar Gupta comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Linked allocation follows Sequential Access. So clearly if it next want to access the n'th block, then it must have to start its access from first block. So to read 20th block in linked allocation , the reading will start from 1st block and total 20 disk block should be access here. premu answered Jun 29, 2020 premu comment Share Follow See all 0 reply Please log in or register to add a comment.