CS372H Spring 2011 Homework 7
Problem 1:
The MegaGiga hard disk rotates at 5400 rpm with an arm seek time given
by = 4 + 0.05t msec, where t is the number of tracks the
arm seeks. Assume a block size of 512 bytes, and 1024 tracks with 512
sector/track.
The disk controller and DMA read or write data from/to disk at a rate of
4MB/sec.
-
What is the storage capacity of the disk?
-
Assume that we are reading a 16K-bytes file where the sectors happen to
be allocated contiguously on the same track. Compute the maximum and minimum
disk throughput that is possible while reading the file?
Problem 2:
You are designing a file system from scratch.
The disk driver allows you complete control over the placement of data
on the disk. Assuming that you have settled for a File Allocation Table
(FAT) architecture, where would be the best place to store the table on
disk?
Problem 3:
The FAT file system uses 16-bit numbers to represent
the cluster number that starts the linked list of the clusters that are
implementing a file. Explain the implications of limiting the cluster numbers
to 16 bits. Modify the FAT file system to use 32-bit numbers to represent
the clusters and show how the limitations of FAT can be lifted.
Problem 4:
Contiguous allocation of files leads to disk fragmentation.
Is this internal or external fragmentation?
Problem 5 (review multi-threads programming)
We have 3 teams: red,
green, and
blue.
A team member calls
Game::myTurn(int color)
when she or he wants to do something and calls
Game::doneTurn()
when she or he is done. At most one team may be doing something at a time.
Each team gets a turn in the order red,
green,
blue,
red,
green,
blue,
and so on. If a team is not ready when the previous team is done with its
turn, the team is skipped and the next ready team gets a chance.
If no team is ready, the first team to request a turn gets the
next turn. Note that many team members of the same
color may want to take a turn; model each as an independent thread.
Write the Game class using condition variables and locks.
Follow the coding standards we have been using.
List Game's synchronization and state variable here:
Game::Game() // constructor
{
}
Game::myTurn(int color)
{
}
Game::doneTurn()
{
}