What do you mean by ‘Biosphere Cycle’?

Biosphere means sphere of life.
The idea of biosphere was suggested by Austrian Geologist Edward Suess nearly a century ago. At that time it was not so important concept. Today, however, the biosphere has become the most important problem faced by man. The basic function of biosphere is that it supports life. It is esteemed that biosphere contains more than three hundred and fifty thousand species of plants and eleven million animal species including man. The biosphere supplies the essential requirements for all those species such as plants, animal and human beings namely light, heat, water, food and living space etc.

Biosphere Cycle :- Maintenance of the biosphere is possible through constant recycling of materials betweenthe biotic (living) and abiotic (non-living) components. These cycles are given below:-

(i) Hydrological Cycle :- The path of water through environment is hydrological cycle.

(ii) Carbon Cycle:- Carbon serves two purposes in the environment
1. It is structural component of organic molecules and
2. The energy holding chemicals bonds it forms for energy storage.

(iii) Nitrogen Cycle:- Organisms cannot exist without amino acids, peptides, nucleic acids and protein all of which are organic molecules containing nitrogen.

(iv) The Phosphorous Cycle:- Minerals become available to organisms after they are released from rocks. Phosphorous cycle is one of the mineral cycle begins when phosphorous compounds are leached from rocks and minerals over long period of time.

(v) The Sulphur Cycle:- Sulphur plays a vital role in organisms, especially as a minor but essential components of proteins. Sulphur compounds are important determinants of the acidity of rainfall, surface water and soil.

(vi) Oxygen Cycle:- Oxygen is the main source of respiratory gas for all terrestrial organisms.

What do you understand by the term 'Global Warming'?

Global Warming: Rise in the temperature of globe (earth) is called global warming. The average global temperature reached 15.39 degree Celsius in 1995 breaking the previous records. Coming of every year will be the hottest. For example, Visakhapatnam recorded a day temperature of 39.6 degree, the highest in the last 100 years on July, 1977. More or less, same is the case with almost all coastel cities of Andhra Pradesh. Global Warming is being felt due to the specific characteristics of the greenhouse gases (GHE). Greenhouse gases are three:
(i) Carbon dioxide CO2
(ii) Water vapour H2O
(iii) Ozone O3

Out of these three gases, only carbon dioxide contributes largely to the greenhouse effect in the earth's atmosphere, because carbon dioxide is much more uniformly distributed in atmosphere. The major supplies of carbon dioxide gas to the atmosphere are:
(i) Eruption of volcanoes
(ii) Respiration of living organisms
(iii) Decay of dead organisms
(iv) Burning of fossil fuels
(v) Cultivation of land.
Contribution to global warming is 24% by industrial processes; 14% by deforestation; 13% by agriculture and 49% by energy use.

What factors contribute to ecological imbalance?

Causes of Eco-Imbalance: The reasons which cause ecological imbalance are given below: If beyond 30% of forest land area is resorted to tree-felling than eco-balance is disturbed. About 95% of the land in the arid and semi-arid regions of the world area in the process of desertification. Desertification means changing land into desert area.

1. Deforestation and Desertification.
2. Aerobic process accumulation enhancing need of BOD, COD and DO emanating from sewage and other wastes.
3. Industrial effluents and Agricultural discharges.
4. Automobiles, more than 40 lakhs surface transport moves on the roads of Delhi only.
5. Industrial chimney Thermal Power Stations, emission of flyash and dust from stone crushers.
6. Population and Gulf-war.

What do you mean by 'Scientific Management'?

Scientific management means the application of scientific methods of study analysis to the problems of management. It is a systematic and thoughtful approach to the job of management as compared to the rule of thumb or trial and error. It is concerned with the scientific bent of mind and is more than merely a set of techniques for improving efficiency.

Scientific management was developed and introduced by F.W. Taylor in 1910.

'Technology adoptation depends upon a number of factors.' Comment.

Factors needing attention of Technology Adoptation:

(a) The technology selected for transfer should be appropriate and the purpose for which it is intended to be transferred.

(b) Status of development is another important issue with regard to transfer of technology.

(c) The technology selected for use should not be so much expensive. It should be competitive otherwise it will not be commercially accepted.

(d) The technology to be transferred should be provided with the backup services. The user of technology should be provided with the services like planning, selection of equipment, layout of the factory, erection, commissioning and trouble shooting during operation.

(e) Evaluation of technology is important before it is tranferred from lab to field or industry. This evaluation has to be done to find out whether the claims made are justified by actual facts. If they are not then that very technology should be dropped.

(f) Transferring agency may be like NRDC is essential because technology transfer is not only a matter of technology but also a matter of commerce and law.

(g) Provision of guarantees with regard to performance of the technology on commercial-scale is equally important.

What is multiplexing? Distinguish between frequency division and time division multiplexing.

Multiplexing is the process of allowing multiple signals from different sources to share common communication channel. That is a single channel is used by different signal sources to send their signals.

There are many types of multiplexing some of them as
(a) TDM (Time Division Multiplexing
(b) FDM (Frequency Division Multiplexing)
(c) WDM (Wavelength Division Multiplexing)
(d) CDM (Code Division Multiplexing

TDM: In TDM signals are separated in time domain. Signals from various sources are allowed to flow through the common line one at a time for fixed time. Suppose there are 4 signal sources, then each signal source will be allowed to use line for a period t. Once all signal sources transmit for period t, the first one again get chance and so on.

FDM: In FDM signals are separated in frequency domain. Signal from each source is modulated to different frequency so that the frequency spectrum after modulation will not overlap. At receiving end, signals are demodulated. (i.e. translated back to original frequency).

What is Modem? Describe its role in Data Communication.

Modem is the short form of Modulator-Demodulator. It is a device through which computer send and receive data from telephone lines.

Computer generates discrete data. They cannot be send through telephone lines which are designed for carrying analog signals. Modem accepts the data from computer and convert into analog signals using modulation procedure called ASK (Amplitude Shift Keying), PSK (Phase Shift Keying) or FSK (Frequency Shift Keying) or a variant of these modulation methods. These analog signals are send over telephone lines. The signals that come through telephone lines are reconverted back to binary (discrete) form by demodulator part of the modem. A modem can accept as well as transmit data serially simultaneously. Normal data transfer rates are 56 kbps, 144 kbps or 288 kbps.

What are different types of file organisations used in contemporary file systems in modern-day operating system? Explain with examples.

File organisation defines how records in a file are related to one another. Different file organisations are designed to optimise performance for one or both file access methods. There are several common file organisations. They are:

(a) SEQUENTIAL FILE: Here records are arranged in a sequence adjacent to one another. Records are accessed sequentially. To read a file record, the records starting from first record onwards is read (or from current record onwards is read) until the desired record is found.

(b) RELATIVE OR DIRECT FILE: Here record occurrences are physically located at an address that is calculated from its primary key field. The calculation of the address from the key field is called hashing. Thus record occurrences are scattered on the storage device instead of being arranged next to one another. Records can be retrieved rapidly applying the hashing formula to the primary key field of the desired record. Relative files are very good for situations where rapid access to a small percentage of records in a file are needed by programs.

INDEXED FILES
Here records are pointed to by indexes. The advantages of an index is that it is relatively small and easy to update. At a maximum, the file will have one index per primary key. This index point to the exact location where data (record) is stored. If not maintained properly, indexes can become corrupt and require rebuilding.

INDEXED SEQUENTIAL FILE: This is a special variation on the indexed file concept. Records are physically arranged in sequence to allow sequential access, in contiguous locations or using a linked list or both. These file also contain an index of record keys and their physical addresses that can be used to provide semi direct access to records within the sequential file. Each program determines how it want to access the records, whether sequentially or via the index.

What is meant by memory hierarchy? Is it possible to have a computer system without any secondary storage? Explain your answer.

Memory Hierarchy is the way in which different type of memory is arranged according to size, cost and speed.

Computer systems can be constructed without secondary storage. There are many computer systems without secondary storage.

An EPROM can be used to used to do initial activities (like booting) when powered ON. Programs can be entered into RAM by typing in and can be executed. Only problem is backup of program and data is not possible normally. In many computer systems EPROM'S are used to as secondary memory.

What is meant by Strategic Information System? Explain briefly where such a system is used and the important components of such a system.

Strategic Information Systems are special types of information system which support the change of goal, operation, products, services or environmental relationships of organisation. Due to strategic information systems, a competitive edge over the other organisations is gained. Computers play an important role in implementing strategic information system. Some places where the system is used are health care, distribution of products, researching of transport operations, eGovernance system for policy management.

Important components of strategic information system are:-

(a) Domain resources like survey forms publicity leaflets, orderforms, service forms etc.

(b) Technological resources like computers, fax machines, telephones, presentation equipments and related software.

(c) Human resource like managers, trained personal, brokers etc.

What are the function of an Operating System? Differentiate between multiprogramming, multiprocessing. Which OS are single user and multiusers? Give example of each.

An Operating System has four major functions. They are:-

(a) Memory management
(b) Processor management
(c) I/O management
(d) Information management

MULTIPROGRAMMING:- It is the process by which CPU executes programs that reside in memory on time sharing basis. In a multiprogramming environment, multiple programs are allowed to reside in memory at the same time. Processor executes one program for a short time and then next one is executed for short time and so on until all programs are executed for a short interval. Then it again take up the first one and execute for another short interval and then next one and so on. This process is repeated until programs are completely executed. If a program is completed it is removed from memory and next program that is ready is loaded into the memory.

MULTIPROCESSING:- In a multiprocessing system there will be more than one processor. Since there are more than one processor, more than one activity can be performed at the same time.

An example of single user operating system is DOS. An example of multiuser operating system is UNIX.

Differentiate between Compilers, assembler and translator. Explain their working and the situations where each is useful.

COMPILERS: They are software that translates program written in high level language to machine language. Compilers are complex programs.

ASSEMBLERS: They are software that translates programs written in assembly language to machine language.

TRANSLATOR: Translators are software than can convert programs written in one language to another language. Compilers, interpreters, assemblers etc. are example of translators.

Compilers use many phases for conversion. They are:-

LEXICAL ANALYSIS: Checking for invalid symbols in program.

SYNTAX ANALYSIS: Checking validity of syntax used.

CODE GENERATION: Convert each statement to equivalent machine code.

CODE OPTIMISATION: Generated code is analyzed for redundancy and optimal code is generated.

Assemblers usually uses two or three phases (passes) for converting assembly language program to machine language program. In the first pass, macro calls are expanded. In the second pass forward references are resolved and in the third pass actual machine code generation is done.

Once software is developed using high level languages, compilers are essential for translation. Similarly, assemblers are required for translation in places where programs are developed in assembly language.

What is Client Server Technology? What are their advantages and disadvantages? Discuss them briefly.

Client Server model consist of a set of clients and a set of servers. Servers are a group of cooperating processes that offer services to users. Users are called Clients. Client and server machines are conected in a computer network. The client sends a request and gets an answer from the server.

Client request contain request for some service (like reading a file etc) The server does the work and returns the data requested or an error code indicating why the work could not be performed. No connection has to be established before use or torn down afterwards the reply message serves as the acknowledgement to the request.

Prime advantage of Client Server Model is its simplicity. It is simple because no connection establishment and disconnection is required. Client sends request and gets its reply.

Another advantage is efficiency. The protocol stack used to implement Client Server Model is simple.

Client Server model allows resource sharing between different users.

Another advantage is high reliability. By having alternate sources of supply of data reliability improves. If one server is down another server may be able to service the request. More and more clients can be easily added in a network. It also provide communication medium for widely separated people.

Disadvantages of Client Server Model are:-

1. Operating system that implements the Client Server model is complicated and costly.

2. It is network dependent. Fault in network, network saturation etc. can affect the performance of system.

3. Security: Easy access to data which can be measured.
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