Distributed Computing University questions 2011

Answer ALL questions.
1. What are the disadvantages of distributed systems?
2. Differentiate between tightly coupled and loosely coupled systems.
3. What is predicate addressing?
4. What do you mean by server crashes and client crashes?
5. What is Synchronization?
6. Explain remote access model.
7. Discuss Fault Tolerance Issues.
8. Write a note on Concurrency Control.
9. What is a query in Distributed DBMS? Explain.
10. What is call by reference? Give an example.
PART B — (4 ? 10 = 40 marks)

PCD lab exercise

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
int ret[100];
static int pos=0;
static int sc=0;

void nfa(int st,int p,char *s)
 {
  int i,sp,fs[15],fsc=0;
  sp=st;
  pos=p;
  sc=st;

Computer Hardware Question 17 - 22

Computer Hardware Question 17: What is the  central processing unit (CPU)?

The CPU and Processing System

Answer:   The  central processing unit is the computer's main processing device. It functions through the interaction of three different units: (1) the control unit that interprets instructions and directs the processing, (2) the arithmetic/logic unit that performs arithmetic operations and makes comparisons, and (3) the primary storage unit that temporarily stores data during processing (main memory).The central processing unit is the most complex of the computer's hardware components, directing most of the information processing activities. Each new generation of CPUs adds new processing capabilities and, at the same time gets faster. As new processing methods are invented, new ways of miniaturizing the required circuits are also devised. This miniaturization has resulted in ever smaller, faster computers. Microcomputers that fit comfortably on your desk now have more processing power than mainframe computers that used to fill an entire room.

Today's CPUs are incredibly complex devices. To understand them, it is best to view them in terms of their function. Functionally, the CPU is composed of two main parts, the control unit and the arithmetic logic unit.
The CPU and processing system is illustrated below.

Computer Hardware Question 12 - 16

Computer Hardware Question 12: What is a  workstation?

Answer:   As PCs and the internet have become more popular, their use has expanded beyond their traditional role for word processing and simple data management. Some manufacturers have designed very powerful microcomputers that have taken over some of the more complex data management tasks that were formerly reserved for mainframes and minicomputers. These more powerful microcomputers have come to be called  workstations (see computer hardware questions 8 through 12 for information about the different types of computers). Workstations are microcomputers in that they are based on a microprocessor. And, like other microcomputers, they are designed to be used by one person at a time. However, workstations are usually faster than PCs, often have more storage then PCs, and may use more complex and powerful operating systems than PCs. Workstations are often used for scientific tasks or for managing detailed design and graphics tasks. Often they are used as  multiprocessing machines: that is, because they are fast and use a powerful operating system, they can be used to carry out more than one type of data-processing task at the same time.

Computer Hardware Question 8 - 11

Computer Hardware Question 8: What is a  mainframe?

Answer:   The largest, most expensive computers are known as  mainframes (see computer hardware questions 8 through 12 for information about the different types of computers). They generally cost hundreds of thousands or even millions of dollars and they usually are used as central data processing and storage devices by large businesses or government agencies. The computer users can usually access the mainframes from many different offices that can be in different buildings or even in different cities. Many people can be in contact with the mainframe at the same time and, at any one moment, the mainframe can be processing several different programs for several different users. For that reason, mainframes are often referred to as  host computers in that they are host to many users in many different locations. Many printers and a variety of storage devices may be attached to the mainframe computer.