ISRO APTITUDE PAPER 2009

1) Special software to craete a job queue is called
a) driver
b) spooler
c) interpreter
d) linkage editer
2)When a process is rolled back as a result of deadlock the difficulty arises is
a) Starvation
b) System throughput
c) low device utilization
d) cycle stealing
3)On recieving an interrupt from an I/O device the CPU
a) Halts for a predefined time.
b) Branches off the interrupt service routine after completion off the current instruction.
c) Branches off to the interrupt service routine immediately.
d) hands over the control of address bus and data bus to the interrupting service.
4) Which of the following is true of the auto increment addressing mode?
1. It is useful in creating sef relocating code.
2)If it is induced in an instruction set architecture , than an additional ALU is required for effective
address calculation.
3) The amount of increment depends on the size of the data item accessed.
a) 1 only.
b)2 only
c) 3 only
d) 2 and 3 only
5) Theprimary purpose of an operating system is
a) To make the most efficient use of the computer hardware.
b) to allow people to use the computer.
c) To make the system programmers employed.
d) to make computers easy to use.
6)consider the cpu intensive processes which require 10,20,30 time units and arrive at time 0,2,6
respectively.how many context switches are needed if the operating system impements a shortest
remaining time first sceduling algorithm?Do not count the context switches at the time 0 and end.
a) 1
b) 2
c) 3
d) 4
7) consider a system having n resources of the same type.These resources are shared by 3 processes
A,B,C .These have peak demands of 3,4,6 respectively.For what value of n deadlock won't occour.
a) 15
b) 9
c) 10
d) 13
8) In which addressing mode the effective address of the operand is computed by adding a constant
value to the content of the register?
a) absolute mode.
b) indirect mode
c) immediate mode
d) index mode
9)the process of organizing the memory into two banks to allow 16 bit and 8 bit data operation is called
a) bank switching
b) indexed mapping
c) two way memory interleaving
d) memory segmentation
10)a one dimensional array A has indices 1-75.Each element is a string and takes up three memory
words. The array is stored in location 1120 decimal. The starting address of A[49] is
a) 1267
b) 1164
c) 1264
d) 1169
11) The microsystems stored in the control memory of a processor have a width of 26 bits. Each
microinstruction is divided into three fields : a microoperation field of 13 bits, a next address field(X),
and a MUX select field(Y). There are 8 status bits in the inputs of the MUX.How many bits are there in
the X and Y fields and what is the size of the control memory in number of words?
a) 10,3,1024
b) 8,5,256
c) 5,8,2048
d) 10,3,512
12)The use of multiple register windows with overlap causes a reduction in the number of memory
accesses for
1.function locals and parameters
2. register saves and restores.
3. instruction fetches.
a) 1 only
b) 2 only
c) 3 only
d) 1,2,and 3
13)Which of the following about relative addressing mode is false?
a) it enables reduced instruction size.
b) it allows indexing of array element with same instruction.
c) it enabkles easy relocation of data.
d) it enables faster address calculation than absulute addressing.
14)Substitution of values for names (whose values are constants) is done in '
a) local optimization
b) loop optimization
c) constant folding
d) strength reduction
15)A root a of eq f(x)=0 can be computed to any degree of accuracy if a good initial approximation x0
is chosen for which
a) f(x0)>0
b) f(x0)f''(x0)>0
c) f(x0)f''(x0)<0
d) f''(x0)>0
16) consider the polynomial p(x)=a0+a1x+a2x*x+a3x*x*x. The mininum number of multipliations
needed to evaluate p on an input x is
a) 3
b) 4
c) 6
d) 9
17)Activities which ensure that the software that has been built , is tracable tocustomer is covered as
part of
a) verification
b) validation
c) maintainnace
d) modeling
18) A testing method which is normally used as the acceptance test for a software system is
a) regression testing
b) integration testing
c) unit testing
d) system testing
19)A locked database file cab be
a) accessed by only one user
b) modified by the users with the correct password.
c) used to hide the sencitive information.
d) updated by more than one user