MadeEasy Test Series: Operating System - File System

Question

A file system with 512 GB disk uses a file descriptor with 16 direct block addresses, 1 indirect block address, 1 doubly indirect block address, 1 triple indirect block address. Size of each disk block is 256 bytes. And size of each disk block address is 8 bytes. The maximum possible file size is:_____ (in GB)

My answer is 0.008 GB

In their solution, they say it's 8 GB, which I think is wrong.

Comments

yes. u r correct

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Thank you very much. I am losing trust in Made Easy test series. Despite giving the correct  answer, I lost 2 marks only because their ans is wrong.

I had one more question. I posted it here but nobody has answered it yet. It is:

For incrementing/decrementing the value of Program Counter (PC) register, is it necessary to switch to Kernel Mode?

Please answer.

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here i think kernel mode ... since PC is processor resisotr.... if in user mode one user is allowed access to other user's process ... this should be not alllowed....

Answer 1

ans is 0.008GB (rounded)

no.  of enteries in single block is =256/8=32; it means each block contain 32 enteries

1 indirect block address point to 32 blocks

 1 doubly indirect block address points to 32*32 blocks

1 triple indirect block address points to 32*32*32 blocks

and size of each block is 256B

so

Total file size is  ((16+32+32^2+ 32^3)*256)/2^30