Consider a file system on a disk that has a logical block size of 512 bytes, and assume that the information about each file (i.e., the folder) is already in memory and that each pointer requires 16 bytes under linked and indexed allocation methods. Answer the following questions: (a) How many blocks are required for storing a 98-KB file under the contiguous, linked, and indexed allocation methods? (b) How many blocks must be read from the disk under linked allocation when the user wants to access data on the 9857th byte of that file?

Consider a file system on a disk that has a logical block size of 512 bytes, and assume that the information about each file (i.e., the folder) is already in memory and that each pointer requires 16 bytes under linked and indexed allocation methods. Answer the following questions: (a) How many blocks are required for storing a 98-KB file under the contiguous, linked, and indexed allocation methods? (b) How many blocks must be read from the disk under linked allocation when the user wants to access data on the 9857th byte of that file?

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

See similar textbooks

Similar questions

Suppose the head of a moving head disk with 200 tracks numbered 0-199 is currently servinga request at track 143. It has just finished a request at track 125. If the queue of requests iskept in the FIFO order,86,147,85,177,94,150,102,175,130What is the total head movement to satisfy these requests for the following disk schedulingalgorithms? First Come First Served Shortest Seek Time First SCAN
Consider a file whose size varies between 2KB and 8MB during its lifetime. It is required that the file be accessible in the face of corrupted disk blocks. State, with reasons, whether or not the following block allocation schemes will be appropriate for implementing the file storage: contiguous, linked and table/indexed
Consider a file system that uses contiguous allocation method. For a disk consists of 100 data blocks, each block is 4KB. What is the maximum and minimum number of files of size 15KB can it save? Find the number of files the disk able to support using (1) link allocation and (2) index allocation, assuming the address is 32 bit.
Consider a file system that uses indexed allocation with a maximum of one index node per file. Suppose the index node occupies 4096 bytes, that each block pointer occupies 4 bytes. Ignore the metadata associated with the file that is usually contained in the index node. How large should a block be (in bytes) so that this scheme is able to completely access files on a 1 GB file system?
Suppose a disk has N cylinders, numbered from 0 to P. At some time, the disk arm is at cylinder X, and there is a queue of disk access requests for cylinders R1, R2, R3, R4. Explain which Disk scheduling algorithm should be the best to be used between the following a) FIFO b) CSCAN c) SSTF d) FSCAN e) CLOOK N: B • • Choose any acceptable numeric numbers for N, P, X, R1, R2, R3 and R4 • • Plagiarism Will be penalized heavily
a) The physical size of a given file is 16384 bytes in a magnetic disk, with each cluster consisting of 8 sectors, each of which having a fixed size of 512 bytes. How many sectors and clusters will the above file take? What will the logical size of the above file be if there is a slack space of 2930 B? How can we make sure that there will be no residues from previously deleted files? discuss b) Suppose that a car has passed the checkpoint, A, towards the checkpoint, B, with an average speed of 150 Km/hr and reached B at 10:35:40. 1- Express the recorded time at point B in seconds. 2- If the car has reached the next checkpoint, B at 10:35:40, what will be time that this car has passed the checkpoint, A, if the distance between A and B is 100 Km? The time should be in hrs-min-sec format. Show all your calculation steps.
Consider a file currently consisting of 100 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) allocationstrategies, if, for one block, the following conditions hold. In the contiguous-allocation case, assume that there is no room to grow at the beginning but there is room to grow at the end. Also assume thatthe block information to be added is stored in memory.a. The block is added at the beginning.b. The block is added in the middle.c. The block is added at the end.d. The block is removed from the beginning.e. The block is removed from the middle.f. The block is removed from the end
Suppose that there is a file system with blocks of 512 bytes in size. For each inode, there are 20 direct blocks, 2 singly-indirect blocks, and 2 doubly-indirect blocks. The size of a pointer is 4 bytes. Calculate the maximum possible size of a file in bytes. Show your work.
Consider a file system that uses indexed file allocation. Disk block size is 1K-byte, and a file pointer is 64 bits (8-bytes). If we assume that an i-node just holds 2 direct entries and 4 single indirect entries, what is the maximum size of a file the system can allow? List the steps that lead to your conclusion.
Consider a Data file of r=30,000 EMPLOYEE records of fixed-length, consider a disk with block size B=512 bytes. A block pointer is P=6 bytes long and a record pointer is P R =7 bytes long. Each record has the following fields: NAME (30 bytes), SSN (9 bytes), DEPARTMENTCODE (9 bytes), ADDRESS (40 bytes), PHONE (9 bytes), BIRTHDATE (8 bytes), SEX (1 byte), JOBCODE (4 bytes), SALARY (4 bytes, real number). An additional byte is used as a deletion marker. Calculate the record size R in bytes. Calculate the blocking factor bfr and the number of file blocks b assuming an unspanned organization. Suppose the file is ordered by the key field SSN and we want to construct a primary index on SSN. Calculate the index blocking factor bfr .
Suppose a file system is based on the indexed allocation strategy for managingblocks. Assume each file has a directory entry giving the file name, first index block,and the length of the file. The first index block points in turn to 128 file blocks andto the next index block. Suppose that each file block contains 4KB of data and theuser is currently reading the 441K-th byte of a file. If the user’s next operation is toread the 1201k-th byte of the same file, how many physical disk I/O operations mustbe performed in order to read that byte? Explain your answer in detail usingdiagrams as appropriate.
Assume that each block has B = 1000 Bytes, and the buffer pool has m = 1001 frames. What is theexact size of the largest file external memory sorting can sort within 3 passes, i.e., pass 0 to pass 2with pass 2 producing only 1 run?