CS-611 Fundamentals and PC Software

Course Code : CS-611
Course Title : Fundamentals and PC Software
Assignment Number : BCA(1)-611/Assign/09
Maximum Marks : 25
Last Date of submission : 30th April, 2009/30th October, 2009



Q. 1 What is Computer System? Explain Structure of Computer.
1. Computer System:
A complete, working computer. The computer system includes not only the computer,
but also any software and peripheral devices that are necessary to make the computer
function. Every computer system, for example, requires an operating system.
A general purpose computer has four main sections: the arithmetic and logic unit (ALU),
the control unit, the memory, and the input and output devices (collectively termed I/O).
These parts are interconnected by busses, often made of groups of wires.
The control unit, ALU, registers, and basic I/O (and often other hardware closely linked
with these) are collectively known as a central processing unit (CPU). Early CPUs were
composed of many separate components but since the mid-1970s CPUs have typically
been constructed on a single integrated circuit called a microprocessor.

Q. 2 What is memory system? Explain the memory hierarchy.
Ans 2: Memory System

The system memory is the place where the computer holds current programs and data that
are in use. There are various levels of computer memory (memory), including ROM,
RAM, cache, page and graphics, each with specific objectives for system operation. This
section focuses on the role of computer memory, and the technology behind it.
Although memory is used in many different forms around modern PC systems, it can be
divided into two essential types: RAM and ROM. ROM, or Read Only Memory, is
relatively small, but essential to how a computer works. ROM is always found on
motherboards, but is increasingly found on graphics cards and some other expansion
cards and peripherals. Generally speaking, ROM does not change. It forms the basic
instruction set for operating the hardware in the system, and the data within remains
intact even when the computer is shut down. It is possible to update ROM, but it's only
done rarely, and at need. If ROM is damaged, the computer system simply cannot
function.
The hierarchical arrangement of storage in current computer architectures is called the
memory hierarchy. It is designed to take advantage of memory locality in computer
programs. Each level of the hierarchy has the properties of higher bandwidth, smaller
size, and lower latency than lower levels.

Most modern CPUs are so fast that for most program workloads, the locality of reference
of memory accesses and the efficiency of the caching and memory transfer between
different levels of the hierarchy are the practical limitation on processing speed. As a
result, the CPU spends much of its time idling, waiting for memory I/O to complete. This
is sometimes called the space cost, as a larger memory object is more likely to overflow a
small/fast level and require use of a larger/slower level.
The memory hierarchy in most computers is:
• Processor registers – fastest possible access (usually 1 CPU cycle), only hundreds
of bytes in size
• Level 1 (L1) cache – often accessed in just a few cycles, usually tens of kilobytes
• Level 2 (L2) cache – higher latency than L1 by 2× to 10×, often 512 KiB or more
• Main memory (DRAM) – may take hundreds of cycles, but can be multiple
gigabytes. Access times may not be uniform, in the case of a NUMA machine.
• Disk storage – millions of cycles latency, but very large
• Tertiary storage – several seconds latency, can be huge
The various major units in a typical memory system can be viewed as forming a
hierarchy of memories (m1,m2,...,mn) in which each member mi is in a sense subordinate
to the next highest member mi-1 of the hierarchy.
Diagram of the computer memory hierarchy


Q. 3 What is printer? Explain different types of printers.
Ans.3

Printer:
The main categories are: - laser printers, ink-jets, dot-matrix, multifunctional, etc.
Normally home computer users will use ink-jets as they are relatively cheap but
superior in quality to dot-matrix. Laser jets and other printers created by new
technology are more expensive and more commonly found in the offices.
Ink-jets (bubble-jets) printers spray ionized tiny drops of ink onto a
page to create an image. This is achieved by using magnetized plates which direct the
ink's path onto the paper in the desired pattern. Almost all ink-jets offer a color option
as standard, in varying degrees of resolution. Ink-jet printers are capable of producing
high quality print which almost matches the quality of a laser printer. A standard ink-jet
printer has a resolution of 300 dots per inch, although newer models have improved on
that. As a rule color link-jet printers can also be used as a regular black and white
printer.
Laser printers operate by shining a laser beam to produce an image on
a drum. The drum is then rolled through a pool, or reservoir, or toner, and the
electrically charged portions of the drum pick up ink. Finally, using a combination of
heat and pressure, the ink on the drum is transferred onto the page. Laser printers print
very fast, and the supply cartridges work a long time. Color laser printers use the same
toner-based printing process as black and white ( B/W) laser printers, except that they
combine four different toner colors. Color laser printers can also be used as a regular
black and white laser printer.

LED/LCD printers are types of electro photographic printers that are
identical to laser printers in most ways. Both LCD (liquid crystal display) and LED
(light-emitting diode) printers use a light source instead of a laser to create an image on
a drum. In most contexts, "laser printer" covers LCD and LED printers as well. The
print process is almost identical, but LED printers use Light Emitting Diodes to charge
the drum, and the other uses Liquid Crystals. These printers produce a very high quality
text and graphics print out.
Impact (Dot-matrix) printers use a set of closely spaced pins and a
ribbon to print letters or other characters on a page. These printers actually impact the
page to print a character, much like a typewriter. Dot-matrix printers vary in terms of
speed and the number of pins they have. They can run at a speed anywhere between 50
and 500 CPS (Characters Per Second). The number of pins, which can vary between 9
to 24, determines the quality of the print job. Dot matrix printers are commonly used
for printing invoices, purchase orders, shipping forms, labels, and other multi-part
forms. Dot matrix printers can print through multi-part forms in a single pass, allowing
them to produce more pages than even high-speed laser printers.
Solid Ink printers are page printers that use solid wax ink sticks in a
"phase-change" process. They work by liquefying wax ink sticks into reservoirs, and
then squirting the ink onto a transfer drum, from where it is cold-fused onto the paper in
a single pass. Solid-ink printers offer better color consistency than do most
technologies, with little variation caused by changes in temperature, humidity, or type
of paper. Solid ink machines have better reliability, because they have fewer
components in comparison, for example with color laser printers.


Dye Sublimation printers are professional devices widely used in
demanding graphic arts and photographic applications. True these printers work by
heating the ink so that it turns from a solid into a gas. The heating element can be set to
different temperatures, thus controlling the amount of ink laid down in one spot. In
practice, this means that color is applied as a continuous tone, rather than in dots, as
with an inkjet. One color is laid over the whole of one sheet at a time, starting with
yellow and ending with black. The ink is on large rolls of film which contain sheets of
each color, so for an A4 print it will have an A4-size sheet of yellow, followed by a
sheet of cyan, and so on. Dye sublimation requires particularly expensive special paper,
as the dyes are designed to diffuse into the paper surface, mixing to create precise color
shades.
Portable printers are usually fairly lightweight and sometimes carry the
option of using a battery instead of drawing power from the computer. Usually they
realize basic print resolutions suitable for plain text printing. You can find on the
market the following types of the portable printers: Thermal printer, Thermal transfer
printer and Ink-Jet printer. The main advantage of thermal and thermal transfer printers
is that they can be very small. The smallest thermal and thermal transfer printers
weigh approximately one pound. Usually the ink-jet portable printer weighs more than
2 pounds. Thermal printers require a special type of paper.
Plotters are large-scale printers that are very accurate at reproducing
line drawings. They are commonly used for technical drawings such as engineering
drawings or architectural blueprints. The two basic types of plotters are called flatbed

plotters and drum plotters. Flatbed plotters are horizontally aligned with a flat surface to
which a piece of paper is attached. The paper remains stationary and the printer moves
pens across the paper to draw the image. Drum plotters, also called upright plotters, are
vertically positioned. They have a drum that the paper rolls on. Drum plotters usually
make more noise and are more compact than flatbed plotters.
Digital Photo printers Many middle range printers are now able to
print photo quality images. Usually an option with color printers, specialist photo print
heads allow a greater resolution to be achieved to improve photo image quality. Photo
ink jet printers expand their gamuts by adding additional ink colors, usually light cyan
and light magenta.
Network printer is a printer that provides output capabilities to all
network users.
Multifunction printers: combine top-quality color ink-jet or laser
printing with plain-paper and PC faxing, color copying and color scanning, telephoningall
in one convenient, space-saving machine. If you work from home or have a small
office a multifunctional device may be ideal.


The Bravo Auto Printer is the world’s first automated CD/DVD
printing system that can truly be called innovative. It combines automatic, roboticbased
CD or DVD printing along with full-color, 2400 dpi disc printing all in one
compact, desktop unit.
Printers for banking: these printers realize innovative technology
and functionality to increase productivity, and reduce costs.
The main categories are: - laser printers, ink-jets, dot-matrix, multifunctional, etc.
Normally home computer users will use ink-jets as they are relatively cheap but
superior in quality to dot-matrix. Laser jets and other printers created by new
technology are more expensive and more commonly found in the offices.
Ink-jets(bubble-jets) printers spray ionized tiny drops of ink onto a
page to create an image. This is achieved by using magnetized plates which direct the
ink's path onto the paper in the desired pattern. Almost all ink-jets offer a color option
as standard, in varying degrees of resolution. Ink-jet printers are capable of producing
high quality print which almost matches the quality of a laser printer. A standard ink-jet
printer has a resolution of 300 dots per inch, although newer models have improved on


that. As a rule color link-jet printers can also be used as a regular black and white
printer.
Laser printers operate by shining a laser beam to produce an image on
a drum. The drum is then rolled through a pool, or reservoir, or toner, and the
electrically charged portions of the drum pick up ink. Finally, using a combination of
heat and pressure, the ink on the drum is transferred onto the page. Laser printers print
very fast, and the supply cartridges work a long time. Color laser printers use the same
toner-based printing process as black and white ( B/W) laser printers, except that they
combine four different toner colors. Color laser printers can also be used as a regular
black and white laser printer.
LED/LCD printers are types of electro photographic printers that are
identical to laser printers in most ways. Both LCD (liquid crystal display) and LED
(light-emitting diode) printers use a light source instead of a laser to create an image on
a drum. In most contexts, "laser printer" covers LCD and LED printers as well. The
print process is almost identical, but LED printers use Light Emitting Diodes to charge
the drum, and the other uses Liquid Crystals. These printers produce a very high quality
text and graphics print out.
Impact (Dot-matrix) printers use a set of closely spaced pins and a
ribbon to print letters or other characters on a page. These printers actually impact the
page to print a character, much like a typewriter. Dot-matrix printers vary in terms of
speed and the number of pins they have. They can run at a speed anywhere between 50
and 500 CPS (Characters Per Second). The number of pins, which can vary between 9
to 24, determines the quality of the print job. Dot matrix printers are commonly used
for printing invoices, purchase orders, shipping forms, labels, and other multi-part
forms. Dot matrix printers can print through multi-part forms in a single pass, allowing
them to produce more pages than even high-speed laser printers.
Solid Ink printers are page printers that use solid wax ink sticks in a
"phase-change" process. They work by liquefying wax ink sticks into reservoirs, and
then squirting the ink onto a transfer drum, from where it is cold-fused onto the paper in
a single pass. Solid-ink printers offer better color consistency than do most
technologies, with little variation caused by changes in temperature, humidity, or type
of paper. Solid ink machines have better reliability, because they have fewer
components in comparison, for example with color laser printers .
Dye Sublimation printers are professional devices widely used in
demanding graphic arts and photographic applications. True these printers work by
heating the ink so that it turns from a solid into a gas. The heating element can be set to
different temperatures, thus controlling the amount of ink laid down in one spot. In
practice, this means that color is applied as a continuous tone, rather than in dots, as
with an inkjet. One color is laid over the whole of one sheet at a time, starting with
yellow and ending with black. The ink is on large rolls of film which contain sheets of
each color, so for an A4 print it will have an A4-size sheet of yellow, followed by a
sheet of cyan, and so on. Dye sublimation requires particularly expensive special paper,
as the dyes are designed to diffuse into the paper surface, mixing to create precise color
shades.

Portable printers are usually fairly lightweight and sometimes carry the
option of using a battery instead of drawing power from the computer. Usually they
realize basic print resolutions suitable for plain text printing. You can find on the
market the following types of the portable printers: Thermal printer, Thermal transfer
printer and Ink-Jet printer. The main advantage of thermal and thermal transfer printers
is that they can be very small. The smallest thermal and thermal transfer printers weigh
approximately one pound. Usually the ink-jet portable printer weighs more than 2
pounds. Thermal printers require a special type of paper.
Plotters are large-scale printers that are very accurate at reproducing
line drawings. They are commonly used for technical drawings such as engineering
drawings or architectural blueprints. The two basic types of plotters are called flatbed
plotters and drum plotters. Flatbed plotters are horizontally aligned with a flat surface to
which a piece of paper is attached. The paper remains stationary and the printer moves
pens across the paper to draw the image. Drum plotters, also called upright plotters, are
vertically positioned. They have a drum that the paper rolls on. Drum plotters usually
make more noise and are more compact than flatbed plotters.
Digital Photo printers Many middle range printers are now able to
print photo quality images. Usually an option with color printers, specialist photo print
heads allow a greater resolution to be achieved to improve photo image quality. Photo
ink jet printers expand their gamuts by adding additional ink colors, usually light cyan
and light magenta.

Network printer is a printer that provides output capabilities to all
network users.
Multifunction printers: combine top-quality color ink-jet or laser
printing with plain-paper and PC faxing, color copying and color scanning ,
telephoning- all in one convenient, space-saving machine. If you work from home or
have a small office a multifunctional device may be ideal.
The Bravo AutoPrinter is the worlds first automated CD/DVD
printing system that can truly be called innovative. It combines automatic, roboticbased
CD or DVD printing along with full-color, 2400 dpi disc printing all in one
compact, desktop unit.
Printers for banking: these printers realize innovative technology
and functionality to increase productivity, and reduce costs.

Q4 Explain the differences between followings:
i. Pipelining and Vector Processing
ii. Synchronous and Asynchronous
iii. Bus topology and Ring topology

Ans 4:

a. Pipelining and Vector Processing

A vector processor, or array processor, is a CPU design where the instruction set
includes operations that can perform mathematical operations on multiple data
elements simultaneously. This is in contrast to a scalar processor which handles one
element at a time using multiple instructions. The vast majority of CPUs are scalar (or
close to it). Vector processors were common in the scientific computing area, where
they formed the basis of most supercomputers through the 1980s and into the 1990s,
but general increases in performance and processor design saw the near
disappearance of the vector processor as a general-purpose
Today most commodity CPU designs include single instructions for some vector
processing on multiple (vectorised) data sets, typically known as SIMD (Single
Instruction, Multiple Data), common examples include SSE and AltiVec. Modern video
game consoles and consumer computer-graphics hardware rely heavily on vector
processing in their architecture. In 2000, IBM, Toshiba and Sony collaborated to create
the Cell processor, consisting of one scalar processor and eight vector processors, which
found use in the Sony PlayStation 3 among other applications.
Other CPU designs may include some multiple instructions for vector processing on
multiple (vectorised) data sets, typically known as MIMD (Multiple Instruction, Multiple
Data), such designs are very special and delicate breeds for dedicated purpose and these
are not commonly marketed for general purpose applications.
The more advanced approach is not the active multiplicity of instructions in parallel but
the active multiplicity in sequence, which led to the pipelining concept.
In software engineering, a pipeline consists of a chain of processing elements (processes,
threads, coroutines, etc.), arranged so that the output of each element is the input of the
next. Usually some amount of buffering is provided between consecutive elements. The
information that flows in these pipelines is often a stream of records, bytes or bits.
The concept is also called the pipes and filters design pattern. It was named by analogy
to a physical pipeline
ii.Synchronous and Asynchronous

Synchronous and asynchronous transmissions are two different methods of
transmission synchronization. Synchronous transmissions are synchronized by an
external clock, while asynchronous transmissions are synchronized by special signals
along the transmission medium.
Whenever an electronic device transmits digital (and sometimes analog) data to another
electronic device, there must be a certain rhythm established between the two devices,
i.e., the receiving device must have some way of knowing, within the context of the
fluctuating signal that it's receiving, where each unit of data begins and where it ends.
Asynchronous transmission
Advantages:
• Simple, doesn't require synchronization of both communication sides
• Cheap, timing is not as critical as for synchronous transmission, therefore
hardware can be made cheaper
• Set-up is very fast, so well suited for applications where messages are generated
at irregular intervals, for example data entry from the keyboard
Disadvantages:
• Large relative overhead, a high proportion of the transmitted bits are uniquely for
control purposes and thus carry no useful information
Synchronous transmission
Advantages:
• Lower overhead and thus, greater throughput
Disadvantages:
• Slightly more complex
• Hardware is more expensive

iii.Bus topology and Ring Topology
Bus Topology
Bus networks (not to be confused with the system bus of a computer) use a common
backbone to connect all devices. A single cable, the backbone functions as a shared
communication medium that devices attach or tap into with an interface connector. A device
wanting to communicate with another device on the network sends a broadcast message onto
the wire that all other devices see, but only the intended recipient actually accepts and
processes the message.
Ring Topology
In a ring network, every device has exactly two neighbors for communication purposes. All
messages travel through a ring in the same direction (either "clockwise" or
"counterclockwise"). A failure in any cable or device breaks the loop and can take down the
entire network.
To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring
topologies are found in some office buildings or school campuses.

Q. 5 What is an E-mail? Explain advantages E-mail. (3 Marks)
Answer-5

Email

Electronic mail, often abbreviated as e-mail, email, or eMail, is any method of creating,
transmitting, or storing primarily text-based human communications with digital
communications systems.
Modern e-mail systems are based on a store-and-forward model in which e-mail
computer server systems, accept, forward, or store messages on behalf of users, who only
connect to the e-mail infrastructure with their personal computer or other networkenabled
device for the duration of message transmission or retrieval to or from their
designated server. Rarely is e-mail transmitted directly from one user's device to
another's.
While, originally, e-mail consisted only of text messages composed in the ASCII
character set, virtually any media format can be sent today, including attachments of
audio and video clips.