Sample Questions for EE6012
This is the revision set of questions for the in-term exam.
OPERATING SYSTEMS – PROCESSES
1) Give a definition for a computer operating system.
2) What does the term POSIX mean is respect to the UNIX/Linux operating
system and what is its significance?
3) Draw a simple block diagram of a Linux operating system and briefly say what is the
purpose of each major block in the kernel.
4) Assume a system, at a given instant, has one running process, three ready processes, two
blocked processes on blocked queue_x and one blocked process on blocked queue_z.
Draw the queuing structure at this instant, showing in your diagram how the queued
PCBs are linked using the relevant PCB fields.
5) With the aid of a state diagram show the various states for a process in a multitasking
system which supports load balancing (i.e. includes the suspended states). Clearly label
all state transitions.
6) Draw a typical PCB (process control block) for a process in a multitasking environment
and briefly state the purpose for each field in your PCB.
7) State clearly what is the difference between a process and a thread.
1) Briefly state what is meant by the following types of process activity:
- Processor-bound activity
- I/O bound activity
2) Draw a diagram for a round-robin scheduler and state one advantage and
one disadvantage for this type of scheduler.
3) Describe the operation of a Multi-Level Feedback Scheduler for a single-processor multi-
tasking system. Use a diagram to show how the queuing structure is arranged. State one
disadvantage to this scheme.
4) For the Microsoft Windows (Win32) scheduler, answer the following:
EE6012 – Sample questions 1
a) Draw a block diagram for the user level environment of the Microsoft Windows
operating system. About ten blocks are expected.
b) Draw a block diagram for the kernel level environment of the Microsoft Windows
operating system. About ten blocks are expected.
c) What in meant by the Win-32 interface?
d) With respect to the Microsoft Windows Win-32 scheduler, please answer the
- How many priority levels exist in the scheduler design?
- What is a thread?
- If a process has a nominal priority level of 13 what is the highest
thread level priority for that process?
- Briefly describe what is meant by starvation prevention in the context
of the Microsoft Windows scheduler?
- State a typical pre-emption time quantum for the Microsoft Windows
scheduler in: 1) a Server configuration and 2) in a Workstation configuration.
1) Briefly describe the elevator algorithm for disk head scheduling within a multi-tasking
system. State the reasons why this solution is better than a first come first served (FCFS)
2) A disk drive is specified to have an average seek access time of 6 milliseconds and a spindle
rotational speed of 10,000 rpm. Calculate the average total latency time required to find a
random sector on this disk drive. Show your calculations.
3) A disk drive is specified to have a spindle rotational speed of 10,000 rpm. Assume that each
track contains 1024 sectors, where each sector is 512 bytes in size. Calculate the raw
read/write data transfer rate in bits/second for a track on this disk drive. Show your
4) In relation to the block size (cluster size) for a file system:
(i) What is considered to be a typical block size?
(ii) State a disadvantage for a large block size
(iii) State a disadvantage for a small block size
5) For the FAT file system:
a) Draw a simple FAT table diagram to show an example of how clusters are mapped to
a small 3-cluster file. In the table indicate ‘free clusters’ and a ‘bad cluster’.
b) If a FAT16 file system uses a cluster size of 16kBytes, what is the maximum
partition size for this system?
6) For a UNIX style file system:
a) Draw a typical i-node structure showing each field entry.
EE6012 – Sample questions 2
b) Draw a diagram showing how the i–node is used to keep track of a file’s disk blocks.
7) A UNIX style file system is implemented using 1kByte (1024) disk blocks and 32-bit size
block addresses. The i-node holds 12 direct block addresses, one single-indirect block
address, one double-indirect block address, and one triple-indirect block address.
Showing your calculations, what is the maximum file size for such a file system, and
what is the maximum file system size?
8) A Linux ext3 file system supports directory entries of dynamic length. Draw a directory
entry data structure to support such a directory entry and briefly explain each field in your
structure. State what is the typical maximum filename size for such a Linux file system.
9) The Linux ext3 file system uses a concept referred as block groups. What is the primary
advantage of using such block groups? Draw a diagram to show the structure of a block
group and name each field. State the purpose of the group descriptor field in the block
10) For a Linux ext3 file system, if the block size is 4kBytes, then what is the maximum size
of a single block group? Show your calculation.
11) Draw a block diagram for the architecture of a Linux Virtual File System (VFS).
Briefly state the purpose of each block in your diagram. Name five types of file systems
that are supported in the Linux VFS.
RAID and disk spanning
1) Describe what is meant by the term ‘RAID’, and state any advantages for RAID.
2) For a RAID level 4 scheme, briefly describe how a failed drive is reconstructed.
3) Explain clearly why RAID level 5 is better than RAID level 4.
4) Draw a block diagram for a hardware RAID scheme showing a single RAID volume and
four disk drives.
5) Briefly describe what the term disk spanning means. Draw a diagram for system with
five logical volumes and five physical disk drives, where the physical disks are grouped
in a group of 2 physical disks and a group of 3 physical disks.
EE6012 – Sample questions 3