Assignment: CS-611 Solved Assignment December 2009

Course Code          : CS-611
Course Title         : Fundamentals and PC Software
Assignment Number    : BCA(1)-611/Assign/09
Maximum Marks        : 25

There are eight questions in this assignment. Answer all questions. You may use illustrations and diagrams to enhance explanations.

Q1: What is Computer System? Explain Structure of Computer. (3 marks)

Answer: Before defining Computer System we must know what a Computer is. According to Oxford Dictionary “A Computer is an automatic electronic apparatus for making calculations or controlling operations that are expressible in numerical or logical terms”. A computer needs software and peripheral devices in order to function as defined earlier. Hence, all the factors, which are responsible for making a computer work properly, are together called Computer System. In short, Computer System is a complete working computer.

Most of today's computer designs are based on concepts developed by John von Neumann referred to as the Von Neumann architecture. Von Neumann proposed that there should be a unit performing arithmetic and logical operation on the data. This unit is termed as Arithmetic Logic Unit (ALU). A control unit directs the ALU to perform specific arithmetic or logic function on the data. Therefore in such a system, by changing the control signal the desired operation can be performed on data.

Q2: What is memory system? Explain the memory hierarchy. (3 marks)

Answer: Before defining “memory system” I would like to define “memory” itself. Computer memory refers to devices that are used to store and retrieve data or instructions on a temporary or permanent basis for use in an electronic digital computer. And these storage devices along with the algorithm and information on how to control and manage them constitute the memory system of a computer.

Memory system exhibits a wide range of technology. Faster memory technology is more expensive and requires power supply till the information needs to be stored, but on the other hand the memory with less cost have very high access time. Thus, the cost versus access time has led to a hierarchy of memory which can be considered to consist of three groups of memory. These are:

(a) Internal Processor Memories: These consist of the small set of high speed registers which are internal to computer and are used as temporary locations where actual processing is done.

(b) Primary or Main Memories: It is large memory, which is fast but not as fast as internal processor memory. This memory is accessed directly by the processor. It is mainly based on integrated circuits.

(c) Secondary Memory/Auxiliary Memory/Backing Store: Auxiliary memory is much larger in size than main memory but is slower than main memory. It normally stores system programs, other instructions, programs and data files. Secondary memory can also be used as an overflow memory in case the main memory capacity has been exceeded. Secondary memories cannot be accessed directly by a processor. First the information of these memories is transferred to the main memory and then the information can be accessed as the information of main memory.

Q3: What is printer? Explain different types of printers. (3 marks)

Answer: A device that prints text or illustrations on paper. There are many different types of printers. In terms of the technology utilized, printers fall into the following categories:

Daisy-Wheel: Similar to a ball-head typewriter, this type of printer has a plastic or metal wheel on which the shape of each character stands out in relief. A hammer presses the wheel against a ribbon, which in turn makes an ink stain in the shape of the character on the paper. Daisy-wheel printers produce letter-quality print but cannot print graphics.

Dot-Matrix: Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations.

Ink-Jet: Sprays ink at a sheet of paper. Ink-jet printers produce high-quality text and graphics.

Laser: Uses the same technology as copy machines. Laser printers produce very high quality text and graphics.

LCD & LED: Similar to a laser printer, but uses liquid crystals or light-emitting diodes rather than a laser to produce an image on the drum.

Line Printer: Contains a chain of characters or pins that print an entire line at one time. Line printers are very fast, but produce low-quality print.

Thermal Printer: An inexpensive printer that works by pushing heated pins against heat-sensitive paper. Thermal printers are widely used in calculators and fax machines.

Q4: Explain the differences between followings:

i. Pipelining and vector processing

ii. Synchronous and asynchronous

iii. Bus topology and Ring topology (3 marks)

Answer:

i. The basic difference between Pipelining and vector processing is that Pipelining provides a way to start a new task before an old one has been completed while vector processing has ability to process vectors, and related data structures such as matrices and multi-dimensional arrays, much faster than conventional computers.

ii. Asynchronous communication is slower than synchronous communication. In synchronous transmission characters are transmitted as groups while in asynchronous transmission, each character is transmitted separately. In synchronous mode, intervals between characters are uniform with no space between consecutive bytes but in asynchronous mode, intervals between characters are uniform with space.

iii. In Bus Topology all stations are connected to a single communication line called Bus while in ring topology each station is attached to an adjacent station. Failure of a station in a ring topology disrupts the ring and a break in the bus can be difficult to locate but limits the range of communications between stations that traverse the broken point.

Q5: What is an E-mail? Explain the advantages of E-mail. (3 marks)

Answer: Electronic mail, often abbreviated as e-mail, is a method of exchanging digital messages, designed primarily for human use.

Advantages of E-mail:

1) Mail is delivered instantly...from your office to anywhere in the world. No other method of delivery can provide this service. Timely buying and selling decisions can be made in a heartbeat.

2) Compared to telephone calls, faxes, or overnight courier service, Email is less expensive.

3) The text of a previous email message can easily be included as part of a reply to that message. Thus, e-mail correspondents are able to keep the replies in context for each message. Including this context is not only polite, but also makes an email message more accurate and understandable.

Q6: Explain how you can protect your machine from computer viruses. Also explain the process of removal of a computer virus from a virus infected machine. (3 marks)

Answer: A machine can be protected by computer viruses by taking the following precautionary measures:

• The CHKDSK command can be incorporated to the AUTOEXEC.BAT to check the disk. If the number of hidden files increases, the matter should be looked into.

• Do not copy pirated software on your system.

• Write protect tags should be used on the original software diskettes.

• Proper backup of all data and program files should be kept.

• Copying of files should be done carefully; a better practice is to write the COPY command in a batch file with CHKDSK command.

• Used floppies should be reformatted.

• Avoid letting the system to be used by unauthorised users.

• Restrict the use of outside floppies

• Do not download suspicious shareware programs.

To remove a computer virus from a virus infected machine, we can delete the infected files if know exactly which file has been infected otherwise we can use anti-virus software to detect and remove the virus.

Q7: Explain how you will handle following problems:

i. You have to recover a deleted file.

ii. You have to remove software from your system.

iii. You have to search a .doc file from C drive.

iv. You need to share a newly created folder with other users. (2 marks)

Answer:

Recover a Deleted File: Open up the Recycle Bin on your desktop, select the file and drag it onto the desktop or into an Explorer window to recover it. Or simply double-click to open the Recycle Bin, select the file, and choose Restore from the pop-up menu to restore it to its original folder.

Remove software from system: Open run command (Win+R) and type appwiz.cpl and press enter or go to control panel and click on “Add or remove programs”. Add or remove programs window appears then select the program that you want to remove and at last click on the remove button to uninstall it from your computer.

Search a .doc File from C Drive: Press window key+F and click on documents that can be found on the left. Now click on the use advanced search options and select C drive under look in category. Finally type *.doc in the “all or part of the document name” text box and press search button. This will show the entire doc file from c drive.

Share a Newly Created Folder with Other Users: Simply drag and drop the newly created folder to shared documents of the computer.

Q8: Create a document using Microsoft-Word for the courses offered in IGNOU BCA Programme. This document should have

• Objective of BCA Programme.

• Guidelines for doing Assignments.

• Attendance Requirements.

• A table having all the BCA courses.

• The pages should have margins as what they are in your programme guide. The document should have page number.

• Proper color and fonts should be used to give more emphasis on certain points. (5 marks)

Answer: "THIS IS A PRACTICAL QUESTION so you have to do according to the question and save the doc file in a CD."