NUMBER SYSTEM,PROGRAMMING LANGUAGE, Network Topologies,Operating System
NUMBER SYSTEM.
Number system in base or radix use Unix symbol for digits. One or more digit are
combined to get a number. The base of the number decides the valid digit that are
used to make a number. In a number the position of digit starts from the right hand
side of the number. The rightmost digit head position 0,the next digit on its left has
position 1, and so on. The digit of a number have two kind of values
Face value
Position value
FACE VALUE -
the face value of a digit is the digit located at that position. For
example, in decimal number 52, face value at position 0 is 2 and face value at position
1 is 5.
POSITION VALUE-
For example in decimal number 52, the position value of digit 2 is100 and the position
value of digit 5is 101. Decimal number have a base of 10.
In computers, we are concerned with four kind of number system
Decimal number system. -. Base 10
Binary number system-. Base 2
Octal number system-. Base 8
Hexadecimal number system--. Base 16
Decimal number system-
All number in this number system are represented as combination of digits 0-9.
For example, 34,5965 and867321.
Binary number system-
All binary number are formed using combination of 0 and 1
For example, 1001,11000011 and 10110101.
Octal number system-
The octal number system consists of 8 digits-. 0 to 7
All octal number are represented using these 8 digits.
For example, 273103,2375.
Hexadecimal number system-
The hexadecimal number system consists of 16 digits – 0 to 9,A,B,C,D,E,F where
(A-10,B-11,C-12,D-13,E-14,F-15)
All hexadecimal number are represented using these 16 digits.
For example, 3FA,87B,113.
Q1. convert 12 to binary ,octal, hexadecimal number system
Binary- (0,1)
2. | 12. |0
2. | 6 |0
2. | 3. |1
2. |. 1. |1
|. 0. |
(1100) binary number
Check the Result (Convert Binary number to decimal equivalent)
1×23+1×22+0×21+0×20=12 -check answer
Octal number- (0, 7)8
8. | 12 |4
8. | 1. |1
|. 0. |
(14)8-. Octal number
Check the Result (Convert octal number to decimal equivalent)Check with answer 1×81+4×80= 8. +. 4=. 12
Hexadecimal number- (0,9,A,B,C,DE,F)
16| 12 | 12 |
| 0 |
Check the Result (Convert hexadecimal number to decimal equivalent)
12* 161+160=. 12 or C
PROGRAMMING LANGUAGE
High level language:-
Since the first high level language in early 1950s, today there are more than 1000 high
level languages. Only a few of them have been truly significant, and even fewer have
been widely used. Some popular high level languages are briefly described below.
The primary objective here is to provide some insight into these languages rather than
detailed knowledge required to write programs in these languages.
FORTRAN
COBOL
BASIC
PASCAL
C and C++
Some more high level languages:
Java
C#
RPG
LISP
SNOBOL
Network Topologies
It determines the various data paths available between any pair of nodes in the
network. Choice of a topology for a computer network depends on a
combination of factors such as:
1. Desired performance of the system.
2. Desired reliability of the system.
3. Size of system.
4. Expandability of the system.
5. Cost of components and services required to implement the network.
6. Availability of communication line.
7. Acceptable delays in routing information between two nodes.
Types of Topology-
Star Topology:-
node performs routing function and centrally control communication between
any two other nodes by establishing a logical path between them.
Advantages:-
1. Star topology has minimal line cost because only n-1 lines are required for
connecting n nodes.
2. Transmission delays between two nodes do not increase by adding new nodes
to a network, because only two links connected any two nodes.
3. If any node other than the host node fails, remaining nodes are unaffected.
Disadvantages:-
1. The system crucially depends on host node. If it fails, entire network fails.
Ring Topology:-
A circular or ring network, in which each node has two communicate subordinates, but there is no mater node for controlling other nodes. A node receives data from one of its two adjacent nodes. The only decision a node has to take is whether the data is for its own use. If it is addressed to it, it utilizes it. Otherwise, it merely passes it to the next node.
Advantages:-
1. Ring network works well where there is no central node4 for making routing
decisions.
2. It is more reliable than a star network because communication is not
dependent on a single central node. If a link between any two nodes fails, or if
one of the nodes fails, alternate routing is possible.
Disadvantages:-
1. In a ring network, communication delay is directly proportional to number of
nodes in the network. Hence, addition of new nodes in a networks increase
communication delay.
2. It requires more complicated control software than star network.
Bus Topology:-
or server is connected to single bus cable through some kind of connector. A
signal from the source travels in both directions to all machines connected all
bus cable until it finds the address on network i.e. the intended recipient. If
the machine address does not match the intended address for the data, the
machine ignores the data. Alternatively, if the data does not match the
machine address, the data is accepted.
Advantages:-
1. Cheap and easy to implement.
2. Require less cable.
3. Does not use any specialized network equipment.
Disadvantages:-
1. Network disruption when computers are added or removed high cost of
managing the network.
2. Single point of failure. A break in the cable will prevent al system from
accessing the network.
3. Difficult to troubleshoot.
Fully connected or Complete (Mesh Topology): -
links make the mesh topology unattractive for LAN's with a large number of stations. On the other hand since are stations are directly linked to all other stations on
exclusive links, this topology allows simultaneous communications between in
number of pairs of stations.
Advantages:-
1. It is very reliable because any link failure will affect only direct
communication between the nodes connected by the link.
2. Each node of the network need not have individual routing capability.
3. Communication is very fast between any two nodes.
Disadvantages:-
of linking a system grows with square of the number of nodes. If there are n
nodes in a network, n(n-1)/2 links are required.
Hybrid Topology:-
limitations. Hence, in reality, a pure star or ring completely connected network is
rarely used. Instead, an organization normally uses a hybrid network that combination
of two or more different network topology. Exact configuration of a network depends
on needs structure of organization. In some cases hybrid network may have
components of star, ring, and completely connected network.
Tree Topology:-
closed loops. Allows users to creates networks using bridges. Message from any site
can be received by all other sites, until it reaches an end point. End point controller
absorbs a message if it reaches end point controller without being accepted by a host.
Advantages:-
1. Message traffic can still flow through the network even if a single node fails.
Operating System
hardware. An operating system is a software which performs all the basic tasks like
file management, memory management, process management, handling input and
output, and controlling peripheral devices such as disk drives and printers.
Operating System, VMS, OS/400, AIX, z/OS, etc.
Definition:-
computer hardware and controls the execution of all kinds of programs.
Following are some of important functions of an operating System.
Memory Management
Processor Management
Device Management
File Management
Security
Control over system performance
Job accounting
Error detecting aids
Coordination between other software and users
Management Memory:-
Main memory is a large array of words or bytes where each word or byte has its own
address.
Main memory provides a fast storage that can be accessed directly by the CPU. For a
program to be executed, it must in the main memory. An Operating System does the
following activities for memory management: Keeps tracks of primary memory, i.e.,
what part of it are in use by whom, what part are not in use.
In multiprogramming, the OS decides which process will get memory when and how
much. Allocates the memory when a process requests it to do so.De-allocates the
memory when a process no longer needs it or has been terminated.
Processor Management:-
In multiprogramming environment, the OS decides which process gets the processor when and for how much time. This function is called process scheduling. An Operating System does the following activities for processor management: Keeps tracks of processor and status of process. The program responsible for this task is known as traffic controller. Allocates the processor (CPU) to a process. De-allocates processor when a process is no longer required.
Device Management
An Operating System manages device communication via their respective drivers. It
does the following activities for device management:Keeps tracks of all devices. The
program responsible for this task is known as the I/O controller. Decides which
process gets the device when and for how much time. Allocates the device in the most
efficient way. De-allocates devices.
File Management:-
These directories may contain files and other directions.An Operating System does the following activities for file management: Keeps track
of information, location, uses, status etc. The collective facilities are often known as
file system. Decides who gets the resources.Allocates the resources. De-allocates the
resources.
Other Important Activities:-
Following are some of the important activities that an Operating System performs:
Security -- By means of password and similar other techniques, it prevents
unauthorized access to programs and data.
Control over system performance -- Recording delays between request for a
service and response from the system.
Job accounting -- Keeping track of time and resources used by various jobs and
users.
Error detecting aids -- Production of dumps, traces, error messages, and other
debugging and error detecting aids.
Types of Operating System
Batch Operating System:-
user prepares his job on an off-line device like punch cards and submits it to the
computer operator. To speed up processing, jobs with similar needs are batched
together and run as a group. The programmers leave their programs with the operator
and the operator then sorts the programs with similar requirements into batches.
The problems with Batch Systems are as follows:
Lack of interaction between the user and the job.
CPU is often idle, because the speed of the mechanical I/O devices is slower than
the CPU.
Difficult to provide the desired priority.
Time-sharing Operating Systems
to use a particular computer system at the same time. Time-sharing or multitasking is
a logical extension of multiprogramming. Processor's time which is shared among
multiple users simultaneously is termed as time-sharing. The main difference between
Multiprogrammed Batch Systems and Time-Sharing Systems is that in case of
Multiprogrammed batch systems, the objective is to maximize processor use, whereas
in Time-Sharing Systems, the objective is to minimize response time.Multiple jobs
are executed by the CPU by switching between them, but the switches occur so
frequently. Thus, the user can receive an immediate response. For example, in a
transaction processing, the processor executes each user program in a short burst or
quantum of computation. That is, if n users are present, then each user can get a time
quantum. When the user submits the command, the response time is in few seconds at
most.The operating system uses CPU scheduling and multiprogramming to provide
each user with a small portion of a time. Computer systems that were designed
primarily as batch systems have been modified to time-sharing systems.
Advantages ofTimesharing operating systems are as follows:
Provides the advantage of quick response
Avoids duplication of software
Reduces CPU idle timerating System ─ Types
Disadvantages ofTime-sharing operating systems are as follows:
Problem of reliability
Question of security and integrity of user programs and data
Problem of data communication
Distributed Operating System
Distributed systems use multiple central processors to serve multiple real-time
applications and multiple users. Data processing jobs are distributed among the
processors accordingly.The processors communicate with one another through
various communication lines (such as high-speed buses or telephone lines). These are
referred as loosely coupled systemsor distributed systems. Processors in a distributed
system may vary in size and function. These processors are referred as sites, nodes,
computers, and so on.The advantages of distributed systems are as follows:
With resource sharing facility, a user at one site may be able to use the resources
available at another.
Speedup the exchange of data with one another via electronic mail.
one site fails in a distributed system, the remaining sites can potentially continue
operating.
Better service to the customers.
Reduction of the load on the host computer.
Reduction of delays in data processing.
Network Operating System
A Network Operating System runs on a server and provides the server the capability
to manage data, users, groups, security, applications, and other networking functions.
The primary purpose of the network operating system is to allow shared file and
printer access among multiple computers in a network, typically a local area network
(LAN), a private network or to other networks.
Examples of network operating systems include Microsoft Windows Server 2003,
Microsoft Windows Server 2008, UNIX, Linux, Mac OS X, Novell NetWare, and
BSD.
The advantages of network operating systems are as follows:
Centralized servers are highly stable.
Security is server managed.
Upgrades to new technologies and hardware can be easily integrated into the
system.
Remote access to servers is possible from different locations and types of
systems.
The disadvantages of network operating systems are as follows:
High cost of buying and running a server.
Dependency on a central location for most operations.
Regular maintenance and updates are required.Real-Time Operating System
A real-time system is defined as a data processing system in which the time interval
required to process and respond to inputs is so small that it controls the environment.
The time taken by the system to respond to an input and display of required updated
information is termed as the response time. So in this method, the response time is
very less as compared to online processing.
Real-time systems are used when there are rigid time requirements on the operation of
a processor or the flow of data and real-time systems can be used as a control device
in a dedicated application. A real-time operating system must have well-defined, fixed
time constraints, otherwise the system will fail. For example, Scientific experiments,
medical imaging systems, industrial control systems, weapon systems, robots, air
traffic control systems, etc.
There are two types of real-time operating systems.
Hard real-time systems
Hard real-time systems guarantee that critical tasks complete on time. In hard
real-time systems, secondary storage is limited or missing and the data is stored in
ROM. In these systems, virtual memory is almost never found.
Soft real-time systems
Soft real-time systems are less restrictive. A critical real-time task gets priority over
other tasks and retains the priority until it completes. Soft real-time systems have
limited utility than hard real-time systems. For example, multimedia, virtual reality,
Advanced Scientific
Projects like undersea exploration and planetary rovers, etc.e – Agriculture Introduction
e-agriculture is the internet platform based on the concept of Linking knowledge to innovation and aimed at promoting sustainable agriculture and rural development at global level through the application of information and communication technology (ict) tools in agriculture sector.
Application of e- agriculture on the basis of ICT
● Farmers can go for interactive voice response . ● Expertise sharing , advisory community always available for any extreme situations faced by a small holder farmers.
● Knowledge gaining as well as sharing at broad level helps farmers to be updated with present market news , crops price, this prevents them from losses which many of the farmers usually faces.
● Internet network and sensor networks provide real time information regarding to net banking ,loans according to their needs so that they can easily copeup from any stressful condition or gain profitability which enhances the financial condition of rural community.
● Data storage and Analysis is most important as it shows the growth of present crop production from previous years and analysis shows the comparison that how much profit or loss occurs from previous one .
Role of ICT in e- agriculture
Information communication and technology consist of all technical means which is used to handle information and aid communication. ICT are making tremendous impact on rural economy due to its wide application and appeal.The circulation of information to farmers has increasing day by day. Rural telecentres provide information on education agricultural and health issues and equip rural citizens with skills on how to use the computers and provide basic litreracy.
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