IT Officer Quiz with Answers Explanation-1

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1)Bipolar RAM usually makes use of
a)DTL circuit
b)RTL high speed circuit
c)TTL high speed circuit
d)All of these

2)Parsing technique that avoids backtracking is
a)top-down parsing
b)recursive-descent parsing
c)predictive parsing
d)both (2) and (3)

3)An Oracle object type has two parts the……..and ………..
a)instance and body
b)Segment and blocks
c)Specification and body
d)Body and Segment

4)After defining the function template, the next step to call it in another function such as…….
a)int()
b)secondary()
c)template()
d)main()

5)As OS program module that selects the next job to be admitted for execution is called as
a)scheduler
b)Compiler
c)Throughput
d)Dispatcer

6)What are not used in case of applet?
a)Read/Write
b)Internet
c)Search Engine
d)All of the above

7)Race condition is avoided by
a)J-K flip flop
b)D Type flip flop
c)T Type flip flop
d)Master Clocked SR flip flop

8)Which type of computers use the 8 bit code called EBCDIC?
a)Minicomputer
b)Mainframe Computer
c)Super Computer
d)Microcomputer

9)In UNIX, Cached disk blocks are managed by the kernel and referred to as-
a)Cache
B)Super Cache
c)Buffer Cache
d)All of the above

10)Critical Section is a program segment
a)which should run in a certain specified amount of time
b)which avoids deadlock
c)where shared resources are accessed
d)which must be endorsed by pair of semaphore operation P and V

Answers:
1)c
Transistor–transistor logic (TTL) is a class of digital circuits built from bipolar junction transistors (BJTs) and resistors. It is called transistor–transistor logic because transistors perform both the logic function (e.g., AND) and the amplifying function (compare with resistor–transistor logic (RTL) and diode–transistor logic (DTL)).
TTL integrated circuits (ICs) were widely used in applications such as computers, industrial controls, test equipment and instrumentation, consumer electronics, and synthesizers. The designation TTL is sometimes used to mean TTL-compatible logic levels, even when not associated directly with TTL integrated circuits, for example as a label on the inputs and outputs of electronic instruments

2)d
A parser is a compiler or interpreter component that breaks data into smaller elements for easy translation into another language. A parser takes input in the form of a sequence of tokens or program instructions and usually builds a data structure in the form of a parse tree or an abstract syntax tree.
Parsing are of two types:
A)Top Down Parsing
B)Bottom up Parsing
Top Down Parsing:
When the parser starts constructing the parse tree from the start symbol and then tries to transform the start symbol to the input. it is called top-down-parsing.
Recursive descent is a top-down parsing technique that constructs the parse tree from the top and the input is read from left to right. It uses procedures for every terminal and non-terminal entity. This parsing technique recursively parses the input to make a parse tree, which may or may not require back-tracking. But the grammar associated with it (if not left factored) cannot avoid back-tracking. A form of recursive-descent parsing that does not require any back-tracking is known as predictive parsing.This parsing technique is regarded recursive as it uses context-free grammar which is recursive in nature.

Backtracking means, if one derivation of a production fails, the syntax analyzer restarts the process using different rules of same production. This technique may process the input string than once to determine the right production.

Bottom-up Parsing
Bottom-up parsers construct parse trees starting from the leaves and work up to the root.Bottom-up syntax analysis is also termed as shift-reduce parsing.The common method of shift-reduce parsing is called LR parsing.

3)c
The specification (or spec for short) is the interface to your applications; it declares a data structure (set of attributes) along with the operations (methods) needed to manipulate the data. The body fully defines the methods, and so implements the spec.

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4)d
C++ templates can be used both for classes and for functions in C++. Templated functions are actually a bit easier to use than templated classes, as the compiler can often deduce the desired type from the function’s argument list. A function template defines a family of functions.
Syntax is:
template function_declaration;
template function_declaration;
function-declaration-with-placeholders

a function declaration: The function name declared become a template name.
function-declaration-with-placeholders :a function declaration where the type of at least one parameter uses the placeholder auto or a constrained type specifier: the template parameter list will have one invented parameter for each placeholder.

A function template by itself is not a type, or a function, or any other entity. No code is generated from a source file that contains only template definitions. In order for any code to appear, a template must be instantiated: the template arguments must be determined so that the compiler can generate an actual function (or class, from a class template.)

5)a
Schedulers in Operating System are the process which decides which task and process should be accessed and run at what time by the system resources. It is required to maintain the multi tasking capabilities of a computer and to keep its performance at the highest level by scheduling the process according to their preferences and need. The Schedulers in Operating System are the algorithms which help in the system optimisation for maximum performance.
These three schedulers are:-
1. Long Term Scheduler
2. Middle Term Scheduler
3. Short Term Scheduler
Short term scheduler selects a process from the ready queue and assigns it to the CPU and it operates more frequently than long term scheduler while long term scheduler transfers a process into the ready queue and hence it occurs less frequently.

6)a
Applet is a special type of program that is embedded in the webpage to generate the dynamic content. It runs inside the browser and works at client side.

7)d
Race condition occurs in a multi-threaded environment when more than one thread try to access a shared resource (modify, write) at the same time. Note that it is safe if multiple threads are trying to read a shared resource as long as they are not trying to change it. Since multiple threads try to race each other to finish executing a method thus the name race condition.
If there is a critical section of code (some shared data which is written) then if you get unexpected value at the end of the execution then it may mean thread interference where 2 or more threads are interleaving. It can be avoided by using Mutex or Semaphores upon critical sections.
In SR flip flop rae condition occurs when both S=R=1 & both the output Q and Q race at the same level.This results in race around condition.This condition can be avoided by using Master Slave SR flip flop.Which comprises of a master flip flop, a slave flip flop and an inverter. Both the flip flops are positive level triggered but inverter connected at the clock input of the slave flip flop forces it to trigger at the negative level.

8)b
Extended Binary Coded Decimal Interchange Code(EBCDIC) is an eight-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems. 256 possible characters (letters of the alphabet, numerals, and special characters) are defined.

9)c
The kernel could read and write the file directly from the hard disk and put it in memory and vice versa but the response time and throughput will be very low in this case because of disks sow data transfer speed.
To minimize the frequency of disk usage/access the kernel keeps a buffer to store the recently accessed files and/or frequently accessed files. This buffer is called the buffer cache.
The Unix buffer mechanism consists of two parts.
The first part is a sequence of buffer headers which are used to identify the buffers. Each buffer header is a data structure (, just like inode,) which is used to store the information for the physical buffer it represents.
The second part of the buffer mechanism consists of a fixed array of memory blocks which are used as system buffers.

10)c
Critical section is a piece of code that accesses a shared resource (data structure or device) that must not be concurrently accessed by more than one thread of execution. A critical section will usually terminate in fixed time, and a thread, task or process will have to wait a fixed time to enter it (aka bounded waiting). Some synchronization mechanism is required at the entry and exit of the critical section to ensure exclusive use, for example a semaphore.When one process is executing shared modifiable data in its critical section, no other process is to be allowed to execute in its critical section. Thus, the execution of critical sections by the processes is mutually exclusive in time.

  • Tanya

    Sir, Can you please specify the topics or rather please provide some notes on compiler design basics???