COMPUTER SCIENCE AND APPLICATIONS QUESTION AND ANSWERS

COMPUTER SCIENCE AND APPLICATIONS QUESTIONS AND ANSWERS

1. The following features are needed to implement top down parsing
a. Source string maker
b. Prediction making mechanism
c. Matching and Backtracking mechanism
Ans. All of the above.

2. A macro definition consists of
a. A macro prototype statement
b. One or more model statements
c. Macro pre-processor statements
Ans. All of the above.

3. The main reason to encrypt a file is to
Ans. Secure it for transmission.

4.Which of the following is not a key piece of information, stored in single page table entry, assuming pure paging and virtual memory
Ans. A reference for the disk block that stores the page.

5. A UNIX device drive is
Ans. Structured into two halves called top half and bottom half.

6.The following is not a layer of IO management module
a.PICOS(Physical Input Output Control System)
b.LICOS(Logical Input Output Control System)
c. FS(File System)
Ans. MCS (Management Control System).

7. Which amongst the following is not a valid page replacement policy?
a. LRU Policy (Least Recently Used)
b.FIFO Policy (First in first out)
c.Optimal page replacement policy
Ans. RU policy (Recently Used)

8.An assembly language is a
Ans. Low level programming language.

9. TII stands for
Ans. Table of incomplete instruction.

10.An analysis, which determines the syntactic structure of the source statement, is called
Ans. Syntax analysis.

11. Action implementing instruction's meaning are actually carried out by
Ans. instruction execution.

12. The field containing a segment index or an internal index is called
Ans. Target datum.

13. A program in execution is called
Ans. Porcess.

14.Jobs which are admitted to the system processing is called
Ans. long-term scheduling.

15.A set of techniques that allow to execute a program which is not entirely in memory is called
Ans. Virtual memory.

16.SSTF stands for
Ans. Shortest-Seek-Time-First.

17. Before proceeding with its execution, each process must acquire all the resources it needs is called
Ans. hold and wait.

18. Virtual memory is
Ans. used in all major commercial operating systems.

19.Relocation bits used by relocating loader are specified by
Ans. Assembler or Translator.

20.Resolution of externally defined symbols is performed by
Ans. Linker.

21.Relocatable programs
Ans. Can be loaded almost anywhere in memory

22.page stealing
Ans. is taking page frames other working sets.

23. The total time to prepare a disk drive mechanism for a block of data to be read from its
Ans. Latency plus seek time.

24. To avoid race condition, the maximum number of processes that may be simultaneously inside the critical section is
Ans. One.

25.The memory allocation scheme subject to "external" fragmentation is
Ans. Segmentation.

26.Page fault frequency in an operating system is reduced when the
Ans. locally of references is applicable to the process.

27.In which of the following page replacement plicies Balady's anomly occurs?
Ans. FIFO (First in First Out)

28.Which of the following are language processors?
a. Assemblers
b. Compiler
c. Interpreter
Ans. All of the above.

29. Virtual memory can be implemented with
Ans. Segmentation, Paging

30.Recognition of basic syntatic constructs through reductions, this task is performed by
Ans. Syntax analysis.

31. A Grammar for  a programming language is a formal description of
Ans. Structure.

32.Swapping is a technique of temporarily removing inactive programs from the memory of computer system.

33. Ageing is a technique of improving the priority of process waiting in Queue for CPU allocation.

34.Latency Time is the required by a sector to reach below read/write head.

35. Which of the following is most general phase structured grammar?
a.Regular
b.Context-Free
Ans. Context- Sensitive.

36. File record length
Ans. Should be chosen to match the data characteristics.

37. A public key encryption system
Ans. Allows only the correct receiver to decode the data.

COMPUTER SCIENCE AND APPLICATIONS 

1. Translator for low level programming language were termed as 
Ans. Assembler.

2. Analysis which determines the meaning of a statement once its grammatical structure becomes known is termed as 
Ans. Semantic analysis.

3. Load address for the first word of the program is called 
Ans. load address origin.

4. Symbolic name can be associated with
Ans. data or instruction.

5. The translator which perform macro expansion is called 
Ans. a Macro pre-processor.

6. Shell is the exclusivefeature of
Ans.  UNIX.

7. A program in execution is called 
Ans. Process.

8. Interval between the time of submission and completion of the job is called
Ans. Turnaround time.

9. A schedular which selects processes from secondary storage device is called  
Ans. Medium term schedular.

10. The scheduling in which CPU is allocated to the process with least CPU-burst time is called 
Ans. Shortest job first Scheduling.

11. The term 'page traffic' descries 
Ans. the movement of pages in and out of memory.

12. The "turn-around" time of a user job is the 
Ans. total time taken to execute the job.

13. The following can be used as a criterion for classification of data structures used in language processing
Ans.  Nature of a data structure, Purpose of a data structure, Lifetime of data structure.

14. Memory utilization factor shall be computed as follows
Ans.  memory in use/total memory connected.

15. Program "preemption" is 
Ans. forced de allocation of the CPU from a program which is executing on the CPU.

16. An assembler is
Ans. machine dependent.

17. Which of the following is not a fundamental process state
Ans. blocked state 

18.'LRU' page replacement plicy is 
Ans. Least Recently Used.

19. Which of the following is true?
Ans.Block cipher technique is an encryption technique and b. Stream cipher technique is an encryption technique

20. Which of the following approaches do not require knowledge of the system state?
a. deadlock detection
b. deadlock prevention
c. deadlock avoidance
Ans.None of the above.

21. Program generation activity aims at
Ans.Automatic generation of program

22. Which among the following is not an advantage of Distributed systems?
a.Incremental growth
b. resource sharing
c.none of the above
Ans. Reliability.

23.An imperative staement indicates an action to be performed during execution of assembled program

24. Which of the  loader is executed when a system is first turned on or restarted
Ans. Bootstrap loader.

25. Poor response time is usually caused by 
a.process busy
b.high I/O rates
c.high paging rates
Ans. Any of the above.

26."Throughput" of a system is Number of programs processed by it per unit time

27.The "blocking factor" of a file is The number of logical records in one physical record.

28.which of these is a component of a process precedence sequence?
a.process name
b.sequence operator ';'
c. concurrency operator '.'
Ans. all of the above

29.Which among the following is vallid syntax of the Forkand Join primitive?
Ans. Fork<label>
     join<var> 

30.Nested Macro calls are expanded using the 
Ans. LIFO - Last In First Out

31.A parser which is a variant of top-down parsing without backtracking is 
Ans. Recursive Descend.

32. The expansion of nested macro calls follows
Ans. LIFO rule.

33.In a two-pass assembler, the task of the Pass II is to
Ans. synthesize the target program.

34.A linker program
Ans. links the program with other programs needed for its execution

35.Which scheduling policy is most suitable for a time-shared operating system
Ans. Round-Robin

36.A critical section is a program segment where shared resources are accessed.

37.An operating system contains 3 user processes each require 2 units of resource R. 
The minimum number of units of R such that no deadlocks will ever arise is 4.

38.Locality of reference implies that the page reference being made by a process
Ans. is likely to be the one of the pages used in the last few page references.

39.Which of these is not a part of Synthesis phase
Ans. Perform LC processing

40.The syntax of the assembler directive EQU is
Ans. <symbol> EQU <address space>

DBMS : Normalization

What is Normalization?
Normalization is the process of efficiently organizing
data in a database. There are two goals of the
normalization process: eliminating redundant data
(for example, storing the same data in more than one
table) and ensuring data dependencies make sense
(only storing related data in a table). Both of these
are worthy goals as they reduce the amount of space
a database consumes and ensure that data is
logically stored.

The Normal Forms:
The database community has developed a series of
guidelines for ensuring that databases are
normalized. These are referred to as normal forms
and are numbered from one (the lowest form of
normalization, referred to as first normal form or 1NF)
through five (fifth normal form or 5NF). In practical
applications, you'll often see 1NF, 2NF, and 3NF along with the occasional 4NF. Fifth normal form
is very rarely seen and won't be discussed in this article.
Before we begin our discussion of the normal forms, it's important to point out that they are
guidelines and guidelines only. Occasionally, it becomes necessary to stray from them to meet
practical business requirements. However, when variations take place, it's extremely important
to evaluate any possible ramifications they could have on your system and account for possible
inconsistencies. That said, let's explore the normal forms.

First Normal Form (1NF)
First normal form (1NF) sets the very basic rules for an organized database:
For more details, read Put t ing your Dat abase in First Normal Form

Second Normal Form (2NF)
Second normal form (2NF) further addresses the
concept of removing duplicative data:
Eliminate duplicative columns from the same table.
Create separate tables for each group of related data and identify each row with a unique
column or set of columns (the primary key).
of a table and place them in separate tables.
Create relationships between these new tables and
their predecessors through the use of foreign keys.

Third Normal Form (3NF)
Third normal form (3NF) goes one large step further:
Meet all the requirements of the second normal form.
Remove columns that are not dependent upon the primary key.

Boyce-Codd Normal Form (BCNF or 3.5NF)
The Boyce-Codd Normal Form, also referred to as the "third and half (3.5) normal form", adds
one more requirement:
Meet all the requirements of the third normal form.
Every determinant must be a candidate key.

Fourth Normal Form (4 NF)
Finally, fourth normal form (4NF) has one additional requirement:
Meet all the requirements of the third normal form.
A relation is in 4NF if it has no multi-valued dependencies.

Remember, these normalization guidelines are cumulative. For a database to be in 2NF, it must
first fulfill all the criteria of a 1NF database.

Meet all the requirements of the first normal form.
Remove subsets of data that apply to multiple rows