Consider a file system on a disk that has both logical and physical block sizes  of 512 bytes. Assume that the information about each file is already in memory. For each of the three  allocation strategies (contiguous, linked, and indexed), answer the following question: If we are  currently at logical block 10 (the last block accessed was block 10) and want to access logical block 4,  how many physical blocks must be read from the disk?

I need answer fast please

Consider a file system that uses a modifed contiguous-allocation scheme with support for extents. A file is a collection of extents, with each ex- tent corresponding to a contiguous set of blocks. A key issue in such systems is the degree of variability in the size of the extents. What are the advantages and disadvantages of the following schemes: a. All extents are of the same size, and the size is predetermined. b. Extents can be of any size and are allocated dynamically. c. Extents can be of a few fixed sizes, and these sizes are predeter- mined.

Consider a file currently consisting of 83 blocks. Assume that the file control block (and the index block, in the case of indexed allocation) is already in memory. Calculate how many disk I/O operations are required for contiguous, linked, and indexed (single-level) allocation strategies, if, for one block, the following conditions hold. In the contiguous allocation case, assume that there is room to grow in the beginning and in the end. Assume that the block information to be added is stored in memory. For linked allocation, there is a head and tail pointer pointing respectively to the first and last node. Note that while calculating the total number of I/O operations for each, also indicate how many are from r (read) and w (write). For each part, if there is more than one answer, choose the one that gives you the least number of I/O operations. The block is removed from the beginning The block is added after 41st block The block is removed from the end Assumptions: Read one whole…

Consider a memory of size 8KB (8192 bytes) that allows dynamic, variable sized partitioning among processes and uses a linked list to keep track of free spaces (hereafter referred to as the free list) in the memory at any given time. Assume that there are 6 processes and assume that their memory size requirements (in bytes) are as given below: Р1: 500, Р2: 600, Р3: 1300, Р4: 2000, Р5: 100, Р6: 200 Assume that the initial state of the free list is as shown below (BA is the base address and Sz is the size of each free space): ВА: 0; Sz: 1100 — ВА: 1200; Sz: 600 > BА: 2000; Sz: 1800> ВА: 6000%; Sz 400

Consider a file system that uses a modifed contiguous-allocation scheme with support for extents. A file is a collection of extents, with each ex- tent corresponding to a contiguous set of blocks. A key issue in such systems is the degree of variability in the size of the extents. What are the advantages and disadvantages of the following schemes: a. All extents are of the same size, and the size is predetermined. b. Extents can be of any size and are allocated dynamically. c. Extents can be of a few fixed sizes, and these sizes are predeter- mined.

correct answer is 13. Can you explain by sperately please?

Requests are not usually uniformly distributed. For example, a cylinder containing the file system FAT or inodes can be expected to be accessed more frequently than a cylinder that only contains files. Suppose you know that 50 percent of the requests are for a small, fixed number of cylinders. a. Would any of the scheduling algorithms discussed in this chapter be particularly good for this case? Explain your answer. b. Propose a disk-scheduling algorithm that gives even better performance by taking advantage of this "hot spot" on the disk. c. File systems typically find data blocks via an indirection table, such as a FAT in DOS or inodes in UNIX. Describe one or more ways to take advantage of this indirection to improve the disk performance.