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BCS-o11 Solved Assignment 2022-
Course Code BCS- Course Title Computer Basics and PC Software Assignment Number BCA (1)/011/Assignment/2022- Maximum Marks 100 Weightage 30%
. 31st October, 2022 (For July Session) Last Dates for Submission ) ; 15th April, 2023 (For Januarv Session)
Note This assignment has three questions of 80 marks Answer all the questions Rest 20 marks are for viva voce You may use ulustrations and diagrams to enhance explanations Please go through the guidelines regarding assignments given in the Programme Guide for the format of presentation Please give precise answers The word linut for cach part ts 200 words.
Q1. (Covers Block 1)
(7 x 4 = 28)
a) What 1s VLSI? How did it change the design of a computer system? Explain the working of von Neumann Architecture with the help a diagram. Also explain the process of execution of an instruction for a von Neumann machine.
Solution:
VLSI:
VLSI (Very Large Scale Integration) is one of the most widely used technologies for microchip processors, integrated circuits (IC) and component designing. It was initially designed to support hundreds of thousands of transistor gates on a microchip which, as of 2012, exceeded several billion. All of these transistors are remarkably integrated and embedded within a microchip that has shrunk over time but still has the capacity to hold enormous amounts of transistors.
The first 1 mega byte RAM was built on top of VLSI design principles and included more than one million transistors on its microchip dye.
How VLSI change the design of a Computer System?:
The VLSTIC circuits design flow is shown in the figure below. The various levels of design are numbered and the blocks show processes 1n the design flow.
Specifications comes first, they describe abstractly, the functionality, interface, and the architecture of the digital IC circuit to be designed.
Design Specifications i Schematic Capture 1 Create Symbol 1 Simulation t Layout
Design Rule^ — Check
Extraction
Layoutvs. Schematic Check
Post-Layout Sim.
Behavioral description is then created to analyze the design in terms of functionality, performance, compliance to given standards, and other specifications
RTL description is done using HDLs This RTL description is simulated to test functionality From here onwards we need the help of EDA tools.
RTL description is then converted to a gate-level netlist using logic synthesis tools A gatelevel netlist is a description of the circuit in terms of gates and connections between them, which are made in such a way that they meet the timing, power and area specifications.
Finally, a physical layout is made, which will be verified and then sent to fabrication.
Working of Von Neumann Architecture :
Von-Neumann proposed his computer architecture design in 1945 which was later known as Von- Neumann Architecture. It is a design model for the modern computers which has central processing unit (CPU) and the concept of memory used for storing both data and instructions. This model implements the stored program concept in which the data and the instructions both are stored in the
The Central Processing Unit can also be defined as an electric circuit responsible for executing the instructions of a computer program
The CPU performs a variety of functions dictated by the type of instructions that are incorporated in the computer.
The major components of CPU are Arithmetic and Logic Unit (ALU), Control Unit (CU) and a vanety of registers.
(i) Arithmetic and Logic Unit (ALU)
The Arithmetic and Logic Unit (ALU) performs the required micro-operations for executing the instructions. In simple words, ALU allows arithmetic (add, subtract, etc.) and logic (AND, OR, NOT, etc.) operations to be carried out.
(ii) Control Unit
The Control Unit of a computer system controls the operations of components like ALU, memory and input/output devices.
The Control Unit consists of a program counter that contains the address of the instructions to be fetched and an instruction register into which instructions are fetched from memory for execution
(iii) Registers
Registers refer to high-speed storage areas in the CPU. The data processed by the CPU are fetched from the registers.
Following is the list of registers that plavs a crucial role in data processing.
Registers | __ Description MAR (Memory Address Register)
This register holds the memory location of the data that needs to be accessed.
MDR (Memory Data Register) his^ register^ holds^ the^ data^ that^ is being^ transferred^ to or from memory AC (Accumulator) [[This register holds the intermediate arithmetic and logic results.
PC (Progra(P mc ounter)ter fee^ is register d^ contains^ the^ address^ of the^ next^ instruction^ to be
CIR (Current Instruction : This register contains the current instruction during processing. Register)
- Buses
Buses are the means by which information is shared between the registers in a multiple-register configuration system.
A bus structure consists of a set of common lines, one for each bit of a register, through which binary information 1s transferred one at a time. Control signals determine which register is selected by the bus during each particular register transfer
Von-Neumann Architecture comprised of three major bus systems for data transfer
Bus Description Address _ ||Address Bus carries the address of data (but not the data) between the processor and the Bus | memory. (^) —_____— Data Bus carries data between the processor, the memory unit and the input/output per riie^ devices. a aes sas — is fem Ue ee ee Control Bus carries signals/commands from the CPU.
Data Bus
Bus
- Memory Unit
A memory unit is a collection of storage cells together with associated circuits needed to transfer information in and out of the storage. The memory stores binary information in groups of bits called words. The internal structure of a memory unit is specified by the number of words it contains and the number of bits in each word.
(b) What are the different standards of representing character in a computer? Name and explain any two such standards with the help of examples. List the ASCII codes of all the decimal digits.
Solution:
Different standards of representing character in a computer :
1 ASCII (American Standard Code for Information Interchange)
. UTF-32 (Unicode Transformation Format 32-bit)
- UTF-16 (Unicode Transformation Format 16-bit)
- UTF-8 (Unicode Transformation Format 8-bit) 5 ISCII (Indian Script Code for Information Interchange)
to
ASCII:
UTF-32 allows characters to be encoded as 4 bytes at anv code point from 00000000 to 0010FFFF. For example, the string "ABC" in UTF-32 is encoded as x"000000410000004200000043"
List the ASCII codes of all the decimal digits :
ASCII Character Decimal NULL Oo SOH 1 STX 2 ETX 3 EOT 4 ENQ 5 ACK 6 BELL 7 BS 8 TAB 9
(c) Convert the following numbers as directed
(i) Decimal 197.0625 into equivalent binary and hexadecimal. (11) Decimal 4567654 into binary and hexadecimal (11) String “Character Codes of alphabets and special character $ #” to ASCII band UNICODE strings. (1. ) Hexadecimal ABCDFFED to decimal and binary
Solution:
(i) Decimal 197.0625 into equivalent binary :
In 197,0625, whole number part = 197 and fractional part = 0.
@® First converting whole number part (ie 197)
Remainders 2| 197 17 2/98 0 2/49 1 2| 24 0 2/12 0 2/6 0 2|3 1 21- 0
Therefore, (1497)49 = (41000101) 9
® Converting fractional part (e., 0.0625)
0.0625 X 2 = 0.1250 |
0.1250 X 2 = 0.2500 |
0.2500 X 2 = 0.5000 |
0.5000 X 2 = 1.0000 |
Therefore, (0.0625),9 = (0.0001),
Hence, (197.0625),9 = (41000101), + (0.0001), = (11000101.0001), (Answer)
Decimal 197.0625 into equivalent hexadecimal :
In 197.0625, whole number part = 197 and fractional part = 0 0625
@® First converting whole number part (i e. 197)
Remainders 16|197 5 16112, C 0
Therefore, (197), = (C5)
@® Converting fractional part (1.e., 0.
0.0625 X 16 = 1.
(iii) String “Character Codes of alphabets and special character $ #” to ASCII:
(Character Codes of alphabets and special character $ #)string = (67 104 97 114 97 99 116
101 114 32 67 111 100 101 115 32 111 102 32 97 108 112 104 97 98 101 116 115 32 97 110 100 32 115 112 101 99 105 97 108 32 99 104 97 114 97 99 116 101 114 32 36 32 35) Asc
String “Character Codes of alphabets and special character $ #” to UNICODE strings :
(Character Codes of alphabets and special character $ #) ying = Qu 043\u 068\u O61\u
072\u 061\u 063\u 074\uU 065\u 072\u 020\u 043\u O6F\u 064\u 065\u 073\u 020\u oO6F\u 066\u 020\u 061\u 06C\u 070\u 068\u 061\u 062\u 065\u 074\u 073\u 020\uU 061\u O6F\u 064\u 020\u 073\u 070\u 065\u 063\u 069\u 061\u 06C\u 020\u 063\u 068\u 061\u 072\u 061\u 063\u 074\U 065\U 072\uU O20\Uu 024\U 020\U 023) UNICODE
(iv) Hexadecimal ABCDFFED to decimal :
ABCDFFED Place Vaiue
| 343x16° 14x 16 | | 15x 16° 15x
- 13x 16° 12x 16° —— ——11x 16°
10x 16"
Now, multilying each digit with its place value and adding the products :
(ABCDFFED),¢ = 10 x 167 + 11 x 16° + 12 x 165 + 13 x 164 + 15 x 163 +15 x 167 + 14 x 16! +
13 x 16°
= 2684354560 + 184549376 + 12582912 + 851968 + 61440 + 3840 + 224 +
= (2882404333)
Therefore, (ABCDFFED),¢ = (2882404333)
Hexadecimal ABCDFFED to binary :
Haxadecimal to its equivalent 4-bit Binary digits are shown below:
Hexadecimal Binary oO 0000 1 ooo 2 0010 3 ool 4 0100 5 0101 6 0110 7 oll 8 1000 9 1001 A 1010 B 1011 Cc 1100 D 1101 E 1110 F 1141
To convert haxadecimal number to binary, we write 4-bit bmary equivalent to each hexadecimal digit in the same order.
Therefore, (ABCDFFED),¢ = (10101011110011011111111111101101),,
(d) What is the need of ROM in a computer? How is it different to RAM? Why is cache memory needed even if a computer has RAM and ROM? Why secondary memory is needed?
Solution:
Need of ROM in a computer :
- A Read-Only Memory (ROM) is a non-volatile memory, i.e., the information stored in it is not lost even if the power supply goes off. Thus a Read Only Memory (ROM) is one in which information is stored permanently.
Cache memory 1s a fast semiconductor memory which is used to increase the speed of processing by making current programs and data available to the CPU at a rapid rate. Cache memory is a relatively small, high speed memory that stores the most recent used instructions or data It acts as a high- speed buffer between main memory and the CPU.The cache memory is placed in between CPU and main memory. Access time is the time it takes a device or program to locate information and make it available to the computer for further processing. Cache memory access time is about 0 5 to 2 5 ns which is much less than that of the main memory The access time of main memory is about 50-70 ns Because of its very high cost, the capacity of the cache memory deployed 1s 2 to 3 percent of that of the main memory. The access time of mass storage devices such as hard disks are measured in milliseconds (ms)
Need of Secondary Memory :
The computer uses the main memory RAM and ROM. RAM is volatile and loses its contents when the computer 1s switched off. ROM 1s non-volatile but reads only memory Thus, secondary storage is needed to store data for a long term basis and success whenever needed.
(e) Explain the disk layout of Hard disk and CD-ROM? Also. explain the access time of magnetic disk and CD-ROM. Which of these has smaller access time?
Solution:
Disk layout of Hard disk :
A hard disk is a memory storage device that looks like this:
Track Sector - Track
Disk Sector
The disk is divided into tracks. Each track is further divided into sectors. The point to be noted here is that outer tracks are bigger in size than the inner tracks but they contain the same number of sectors and have equal storage capacity. This is because the storage density is high in sectors of the inner tracks whereas the bits are sparsely arranged in sectors of the outer tracks. Some space of every sector 1s used for formatting. So, the actual capacity of a sector is less than the given capacity.
Disk layout of CD-ROM :
CD-ROM technology uses 12-centimeter (4.7-inch) compact disks (CDs) similar to those used in stereo music systems Each disk can store more than 600 MB, That is approximately equivalent to 400 1.44 MB floppy disks or 300,000 double-spaced pages of text.
sector 66 block sector 09 biock Fig.: CD-ROM Layout
CD-ROMs use long spiral tracks to store data serially, as shown 1n figure above. The track 1s divided into blocks of same size as shown in the figure. ACD-ROM disk rotates at a variable speed so that the pits are read by the laser at a constant linear speed. The speed of the disk 1s adjusted in such a way that the track passes under the read/write head at a constant linear velocity.
Access Time of Magnetic Disk:
Disk access time is how long it takes to obtain the first data character after initiating a request It includes the time to move the read/write head to the track (seek time) and time to rotate the platter to the sector (latency). Disk access time 1s always given as an average, because seek time and latency vary depending on the current position of the head and platter.
Access Time of CD-ROM:
Memory access time is how long it takes for a character in RAM to be transferred to or from the CPU. Fast RAM chips have an access time of 10 nanoseconds (ns) or less See SDRAM.
A Mouse 1s a handy device which can be moved on a smooth surface to cause the movement of a cursor on the screen. It is a pointing device which 1s used to input data and information into the computer system by pointing on it. Physically, a mouse contains a small case, held under one of the user's hands with one or more buttons. For GUI-based systems a mouse 1s an essential pointing- device. The cursor of the mouse moves 1n the same direction in which the mouse ball rolls.
Light pen :
A Light pen ts a pen Itke light-sensitive device. It 1s connected by a wire to the computer terminal to detect the CRT beam when pointed towards the screen and generate a narrow electrical pulse that can be fed to the computer as an input signal It is used to draw on the screen or to point to the display ed objects. It operates by detecting the light emitted by the screen phosphors.
A light pen can work with any CRT monitor but not with LCD monitors. It is used by architects and engineers for CAD applications and editing
(iii) Voice based input:
Voice based input device in which speech is used to input data or system commands directly into a system. Such equipment involves the use of speech recognition processes, and can replace or supplement other input devices.
Some voice input devices can recognize spoken words from a predefined vocabulary, some have to be trained for a particular speaker When the operator utters a vocabulary item, the matching data input
is displayed as characters on a screen and can then be verified by the operator The speech recognition
process depends on the comparison of each utterance with words appearing in a stored vocabulary table The table is created or modified bv using the voice input equipment together with a keyboard. A data item or system command is typed and the related spoken word is uttered, several times. The spoken word is then analyzed and converted into a particular bit pattern that is stored in the vocabulary table.
Keyboard input :
It is the most common input device used for entering data and information into the computer system. This 1s the standard input device attached to all computers The keyboard is a primary device for inputting text by pressing a set of keys. All the keys are neatly mounted in a keyboard connected to the computer system.
In general, a computer keyboard has following kevs : 1 Alphanumeric Keys: It includes letters and numbers
- Punctuation Kevs: These include comma, period, semicolon etc. and
- Special Keys: These can be function keys, control keys, arrow keys and Caps lock keys ete.
All the modern keyboards of computer are classified as. (a) Original PC keyboard having 84 keys; (b) Advance Technology (AT) Keyboard having 101-104 keys; and (c) Multimedia Kevboard having 120 — 140 keys.
(iv) Inkjet printers :
The Inkjet printer works on inkjet technology and produces better quality printouts than dot matrix printers. These print by spraying a controlled stream of tiny ink droplets accurately on the paper forming either dot matrix or solid characters. The printing quality of these printers is very good with a speed of 700 or more characters per second. These are non-impact and hence are relatively silent during the printing process. These printers are easy to use and can be used to print color pages.
Laser printers :
This is a high quality, high speed and high volume technology printer. In laser printers, a laser beam is used to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits it. The drum is then rolled through a reservoir of toner, which 1s picked up by the charged portionsof the drum. Finally, the toner 1s transferred to the paper through a combination of heat and pressure. Laser printers produce very high quality text and graphics but are expensive. The technology used by them is the same as that of photocopying machines. The speed of laser printers varies from 10 pages per minute to 200 page per minute. Laser printers are also called page printers; because they print a whole page at one go.
(g) Explain the characteristics/functions of the following in the context of a computer system: (i) Proxy Server (ii) Motherboard (ii) Scandisk utility (iv) My Documents
Solution
(i) Proxy Server
¢ The client server computing works with a system of request and response. The client sends a request to the server and the server responds with the desired information. ¢ The client and server should follow a common communication protocol so they can easily interact with each other. All the communication protocols are available at the application layer. e Aserver can only accommodate a limited number of cent requests at a tme So it uses a system based to priority to respond to the requests. ¢ Denial of Service attacks hindera servers ability to respond to authentic client requests by inundating it with false requests.
- An example of a client server computing system 1s a web server. It returns the web pages to the clients that requested them
Benefits of using Client/Server Architecture :
- The data is centralized within the system that is maintained in a single place.
* The model is efficient in delivering resources to the client and also requires low-cost
maintenance. ¢ Itis easy to manage, and the data can be easily delivered to the client.
- As the data is centralized, this system is more secure and serves added security to the data.
* Within this type of model, more clients and servers can be embedded into the server, which
makes the performance outstanding and increases the model's overall flexibility.
Difference between File Sharing Architecture and Client/Server Architecture :
In file share architecture, resources could be added as and when necessary or desired. Thus, it provided a low cost entry point with flexible arrangement The drawback was that application logic was executed on the client and server typically provided files to store data It worked fine as long as the volume of data transfer was low and shared usage and content update was low As the number of online users grew, the network traffic got congested and the file sharing got strained. Taking into account the demerits of the file server architectures, the client/ server architecture made its advent.
As the capacity and power of personal computers improved, the need to share the processing demands between the host server and the client workstation increased. This need for greater computing control and more computing value led to the evolution of chent/server technology.
In client/server architecture, the tasks or workloads are partitioned as:
¢ server programs — providers of a resource or service ¢ client programs — requester of resource or service
Chents and servers may reside in the same machine or they typically reside in separate pieces of hardware and communicate over a computer network. A server machine is a host that runs one or more server programs which share their resource with chents. A client does not share any of its resources, but requests a server function or service The server program fulfills the client request. Clients initiate a communication session with the server.
(b) Explain the characteristics of object-oriented programming? What are the advantages of using object-oriented programming?
Solution:
Characteristics of Object-Oriented Programming :
The following are the main characteristics of Object-Oriented Programming:
Encapsulation: is a mechanism through which a protective wrapper is created to hide the implementation details of the object and the only thing that remains externally visible is the interface of the object (i e.: the set of al] messages the object can respond to). Encapsulation prevents code and data from being arbitrarily accessed by other code defined outside the wrapper.
Inheritance: is the process by which a new class is created using an existing class. It is a way to compartmentalize and reuse code since it allows classes to inherit commonly used state and behavior from other classes. The new classes are called the derived classed and the main class is called the parent class.
Polymorphism: Polymorphism is the characteristic of being able to assign a different meaning specifically, to allow an entity such as a variable, a function, or an object to have more than one form. It is the ability to process objects differently depending on their data types and to redefine methods for derived classes
Advantages of using Object-Oriented Programming :
- Modularity for easier troubleshooting
When working with object-oriented programming languages, you know exactly where to look when something goes wrong. “Oh, the car object broke down? The problem must be in the Car class'” You don't have to go line-by-line through all your code
That's the beauty of encapsulation. Objects are self-contained, and each bit of functionality does its own thing while leaving the other bits alone. Also, this modularity allows an IT team to work on
