Q1.Determine the maximum length of cable (in km) for transmitting data at a rate of 500 Mbps in
an Ethernet LAN with frames of size 10,000 bits. Assume the signal speed in the cable to be
2,00,000 km/s
Q2.A scheduling algorithm assigns priority proportional to the waiting time of a process. Every
process starts with priority zero(the lowest priority). The scheduler re-evaluates the process
priorities every T time units and decides the next process to schedule. Which one of the
following is TRUE if the processes have no I/O operations and all arrive at time zero?
Answer : Option BExplaination / Solution:
The given scheduling definition takes two parameters, one is dynamically assigned process
priority and the other is ‘T’ time unit to re-evaluate the process priorities.
This dynamically assigned priority will be deciding processes order in ready queue of round
robin algorithm whose time quantum is same as ‘T’ time units. As all the processes are
arriving at the same time, they will be given same priority but soon after first ‘T’ time burst
remaining processes will get higher priorities
Q4. A RAM chip has a capacity of 1024 words of 8 bits each (1K × 8) . The number of 2 × 4
decoders with enable line needed to construct a 16K × 16 RAM from 1K × 8 RAM is
Answer : Option BExplaination / Solution:
RAM chip size = 1k × 8 [1024 words of 8 bits each]
RAM to construct = 16k × 16
Number of chips required = (16k × 16)/(1k × 8) = 16 × 2 [16 chips vertically with each having 2 chips
horizontally]
So to select one chip out of 16 vertical chips, we need 4 x 16 decoder.
Available decoder is – 2 x 4 decoder
To be constructed is 4 x 16 decoder
So we need 5, 2 x 4 decoder in total to construct 4 x 16 decoder.
Q5. Consider the following sequence of micro–operations
MBR ← PC
MAR ← X
PC ← Y
Memory ← MBR
Which one of the following is a possible operation performed by this sequence?
Answer : Option DExplaination / Solution:
PC content is stored in memory via MBR and PC gets new address from Y. It represents a
function call (routine), which is matching with interrupt service initiation
Q7.Consider an instruction pipeline with five stages without any branch prediction: Fetch
Instruction (FI), Decode Instruction (DI), Fetch Operand (FO), Execute Instruction (EI) and
Write Operand (WO). The stage delays for FI, DI, FO, EI and WO are 5 ns, 7 ns, 10 ns, 8 ns
and 6 ns, respectively. There are intermediate storage buffers after each stage and the delay of
each buffer is 1 ns. A program consisting of 12 instructions I1, I2 ,I3 ,......I12 is executed in this
pipelined processor. Instruction I4 is the only branch instruction and its branch target is I9 . If
the branch is taken during the execution of this program, the time (in ns) needed to complete
the program is
Q8.The following figure represents access graphs of two modules M1 and M2. The filled circles
represent methods and the unfilled circles represent attributes. IF method m is moved to
module M2 keeping the attributes where they are, what can we say about the average
cohesion and coupling between modules in the system of two modules?
Answer : Option AExplaination / Solution:
Coupling = number of external links/number of modules = 2/2
Cohesion of a module = number of internal links/number of methods
Cohesion of M1 = 8/4; Cohesion of M2 = 6/3; Average cohesion=2
After moving method m to M2, graph will become
Coupling = 2/2
Cohesion of M1 = 6/3; Cohesion of M2 = 8/4; Average cohesion=2
Answer : Option CExplaination / Solution:
Clustered index is built on ordering non key field and hence if the index is clustered then the
data records of the file are organized in the same order as the data entries of the index.
Q10. Consider a hard disk with 16 recording surfaces (0 - 15) having 16384 cylinders (0 - 16383)
and each cylinder contains 64 sectors (0 - 63) . Data storage capacity in each sector is 512
bytes. Data are organized cylinder–wise and the addressing format is . A file of size 42797 KB is stored in the disk and the starting disk location of the file is
<1200, 9, 40>. What is the cylinder number of the last sector of the file, if it is stored in a
contiguous manner?