Bbt2103:Computer Operating Systems Question Paper
Bbt2103:Computer Operating Systems
Course:Bachelor Of Business Information Technology
Institution: Meru University Of Science And Technology question papers
Exam Year:2013
a. Explain the following concepts as used in processes/ concurrent programs.
i. Deadlock
ii. Starvation
iii. Race condition
iv. Live lock (8 Marks)
b. Explain the conditions sufficient and necessary to produce deadlock (8 Marks)
c. Explain Two strategies that can be used that deal with deadlocks (2 Marks)
d. Using the table below, demonstrate the process scheduling using FCFS, SJF, SRTN,
and RR (T=3) (12 Marks)
Process Burst time Arrival time
E 10 0
M 3 0
K 1
F 15 4
L 10 5
QUESTION TWO (20 MARKS)
a. Explain the term memory management (2 Marks)
b. State the object of having a memory hierarchy (2 Marks)
c. Draw the memory hierarchy and indicate the variations in terms cost, speed and
capacity (7 Marks)
d. Describe the following memory management techniques highlighting merits
and demerits for each:
i. Fixed partioning
ii. Variable partioning
iii. Paged segmentation (9 Marks)
QUESTION THREE (20 MARKS)
a. Describe the following
i. Concurrency
ii. DMAC (4 Marks)
b. Using suitable examples differentiate between block device and character device
(4 Marks)
c. A disk has 200 tracks with the following request queues: 55, 58, and 39, 18 90, 160,
150, and 38,184. Given that the request is to be honored using FIFO, SSJF, SCAN
and C-SCAN and that the starting track is 100.work out the average seek time. Which
algorithm give the minimum seek time. Does is agree with you expectations.
(12 Marks)
QUESTION FOUR (20 MARKS)
a. Distinguish between system file and user file (4 Marks)
b. Explain why information cannot be stored within the address space of the
processor (2 Marks)
c. Explain the role of operating system in file management (4 Marks)
d. Explain the functions of file Control Block (PCB) (6 Marks)
e. Consider a system in which a directory entry can store up to 16 bock address.
For files not larger than 16 blocks, the 16 address serve as the file’s index
table. For files larger than 16 blocks, the address point to indirect blocks
which in turn point to 256 file blocks each. A block is 1024 bytes. Determine
the size of the power of 2 (4 Marks)
QUESTION FIVE (20 MARKS)
a. Explain the term security with respect computer files (2 Marks)
b. Describe the following security threats to computer system files:
i. Commercial/military espionage
ii. Computer Viruses (6 Marks)
c. Fred’s laptop has the following specifications; Duo core, 1.5 GHZ Intel processor,
64-bit processor, 2GB RAM and 320 GB Hard Disk (5 Marks)
i. Explain the significance of each of the specifications (5 Marks)
ii. If a text page occupies 4o KB, compute the approximate number of pages that
can be stored in the secondary storage. (3 Marks)
iii. If the operating system occupies not less than 32 MB of the main memory and
each running application not less than 12 MB, determine the maximum
number of application that can run simultaneously in the main memory if the
system must always have at least 20% of the main memory free. (4 Marks)
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