4 votes 4 votes A bit-map can be used to keep track of which blocks are free in a file-system’s partition on disk. Assuming, 1 KB block size and a disk size of 40 GB, what is the size of the bit map? Operating System operating-system memory-management bitmap numerical-answers + – Shivangi Parashar 2 asked Nov 27, 2018 • recategorized Aug 1, 2022 by Shubham Sharma 2 Shivangi Parashar 2 5.6k views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments gauravkc commented Nov 27, 2018 reply Follow Share To keep record of whether a block of 1KB is free or not, we need 1 bit. So, number of blocks in 40GB, would be $\frac{40*2^{30}}{2^{10}}$ which is $40*2^{20}$ which is 40M. 1 bit for each. Hence, 40Mb 1 votes 1 votes Shivangi Parashar 2 commented Nov 28, 2018 reply Follow Share given ans is 5 MB 0 votes 0 votes gauravkc commented Nov 28, 2018 reply Follow Share 40Mb or if you want in Bytes then $\frac{40}{8}$ = 5MB My first comment should be 40Mb instead of 40MB. I must edit 2 votes 2 votes Please log in or register to add a comment.
4 votes 4 votes Given, Disk Size=40GB. Block Size=1KB. Since we required one bit per block. Number of blocks=40GB/1KB=40*(2^20) Therefore we require 40*(2^20) bits=5MB. rahul_vicky answered Nov 5, 2019 rahul_vicky comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Number of blocks =disk size/ block size 40GB/1KB 40*2^30/1*2^10 40*2^20 40MB Sazia Tabassum 1 answered Dec 20, 2018 Sazia Tabassum 1 comment Share Follow See 1 comment See all 1 1 comment reply kumar.dilip commented Dec 20, 2018 reply Follow Share Sazia Tabassum 1 you are wrong. So here Number of Blocks = $\frac{40GB}{1KB}$ = 40M ( Blocks) So for each Block, there will require 1 bit to keep track. So, It will be = 40M* 1 bit = 40Mb ( Mega bit Not Byte) To Convert in MB divided by 8 = $\frac{40Mb}{8}$ = 5MB. The answer should be 5 MB. 5 votes 5 votes Please log in or register to add a comment.
0 votes 0 votes I am getting 5MB total number of bolck in File is = 40GB/1KB = 40 M block and each Block Need 1 bit in Bit map then total 40 M bit are needed to represent Bit Map in memory memory for Bit map in Byte = 40M bit / 8 bit = 5MB Himanshu Kumar Gupta answered Sep 21, 2020 • edited Sep 22, 2020 by Himanshu Kumar Gupta Himanshu Kumar Gupta comment Share Follow See all 0 reply Please log in or register to add a comment.