Exercise $1$

Draw a diagram showing the relation between per$-$process$-$open$-$file table and system$-$wide$-$open$-$file table. Separately list the entries in each table for file. How are these tables updated when $($i$)$ a file is opened by an executing process, and $($ii$)$ a file is read?

Exercise $2$

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 $($that is$,$ reads and writes$)$ 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 no room to grow at the beginning but there is room to grow at the end. Also assume that the 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.

Solution

Contiguous Linked Indexed

a

b

c

d

e

f