It describe types of computer languages and operating system

1. UNIT III
INTRODUCTION TO COMPUTER
SOFTWARE

2. PROGRAMMING
LANGUAGES
Programming languages are said to be lower or higher,
depending on whether they are closer to the language the
computer itself uses(lower, which means 0s and 1s)or to the
language that people use(higher, which means more like
english).
FIVE LEVELS OF LANGUAGE :
1. machine language
2. assembly language
3. procedural language
4. problem-oriented language
5. natural language

3. MACHINE
LANGUAGE• machine language is the lowest and most elementary level of
programming language and was the first type of programming
language to be developed.
• machine language is basically the only language that a
computer can understand and it is usually written in hex.
• its execution is very fast and efficient because the computer
can accept the machine code as it is.
• its machine code which is represented inside the computer by
a string of binary digits 0 and 1.
• the symbol 0 stands for the absence of an electric pulse

4. ASSEMBLY
LANGUAGE
• to reduce programming complexity and provide some
standardization,assembly language were developed.assembly
language also known as symbolic language use abbriviation or
mnemonic code to replace the 0s and 1s of machine language.
• Expressed in statement : PACK 210(8,13)
Advantages:
• they are more standardized and easier to use than machine
language.
• They are easier to debug.
Disadvantages:

5. HIGH LEVEL
LANGUAGE• High level language assisted programmers by further reducing
the number of computer operation details they had to specify
so they could concentrate more on the logic needed to solve
the problem.
TYPES OF HIGH LEVEL LANGUAGES:
• procedure oriented
• problem oriented
• natural.
COMPILERS AND INTERPETERS
• For a high level language to work on the computer it must
be translated into machine language .there are two kinds of

6. OPERATING
SYSTEM• An operating system manages and coordinates the functions performed by the
computer hardware, including the CPU, input/output devices, secondary storage
devices, and communication and network equipment.
• The operating software must keep track of each hardware resources, determine
who gets what, when the user will have access to the resource, allocate how
much of the resource the user will be given, and terminate access at the end
of the use period.
FUNCTIONS OF AN OPERATING SYSTEM:
• JOB MANAGEMENT:
job management software manages the jobs waiting to be processed.
• BATCH PROCESSING :
system software is available to support the different methods of processing a
job. With batch processing the most basic method data are accumulated and
processed in group.
• ON-LINE PROCESSING:

7. Classification of operating system:
• Desktop operating systems:
• Os that run on desktop computer are the most common. generally
the os in this category include windows, mac os, dos.
• Sever operating systems:
• computers in a modern organization’s networks are connected to
one another not directly but through powerful computers called
servers that provides security to the networks and route traffic
from one network to another, complicated tasks requiring special
os.

8. Mainframe operating
system:When mainframes and minicomputers dominated the computing world, each
computer company developed its own operating system.
Multi-user operating system:
multi user operating system allow two or more users to run programs at
the same time. Os permit hundreds or even thousands of concurrent users.
Its also called time sharing.
Multitasking operating system:
it allows more than one program to run concurrently. It ability to
execute more than one task at the same time, a task being a program.
Multithreading operating system:
It allows different parts of a single program to run concurrently. It is the

9. COMPUTER
SOFTWARE• Software is a set of instruction or statements that is carried out by the
computer’s CPU.
• Computer software is also called program. Program is an organized list
of instruction that, when executed, causes the computer to behave in a
predetermined manner.
HARDWARE/SOFTWARE INTERACTION:
The program tells the CPU to retrieve a specific piece of information
from memory and to execute a specific interrupt. an interrupt is a signal
informing a program that an event has occurred.
CLASSIFICATION OF SOFTWARE:
• SYSTEM SOFTWARE – include the operating system and all the

10. GENERAL SOFTWARE
FEATURES AND TRENDSGRAPHICAL USER INTERFACE :
a GUI that allows users to interact with electronic devices like
computers, hand-held devices. A GUI offers icons and visual
indicators unlike text based interfaces which use typed
command labels and text to completely represent the
information and actions available to the user.
SOFTWARE SECURITY:
software security is becoming one of the most important and critical
issue for software development.
CLOUD COMPUTING:
• Cloud computing is a computing paradigm in which tasks are
assigned to a combination of connections, software and services
accessed over a network.

11. NETWORK COMPUTING:
• Network computers are becoming popular. Network computers are computers
with minimal memory, disk storage and processor power designed to connect
to a network, especially the internet.
• The idea behind network computer is that many users who are connected to
a network do not need all the computer power they get from a typical
personal computer .
SOFTWARE AS A SERVICE(SAAS):
• In the case of saas the software that is rented rather than purchased.
• Instead of buying software and paying for periodic upgrades, SaaS is
subscription based, and all upgrades are provides during the term of the
subscription.

12. Software development process:
• A structured framework of organized activities needed to create a s/w
development process for the lifecycle of a product.
• A detailed description of the activities required to manage the
development of a software product, from requirements analysis definition
through implementation and maintenance.
• Supporting documents including requirements definition, system analysis,
design documents, user manuals, training documents, error guides etc.

13. Overview of SDLC phases:
• Project start up
• Requirements analysis and specification
• System analysis
• high level design
• Low level design
• Coding and unit testing
• System/integration testing
• Accepting testing
• Implementation
• Project windup
• Project maintenance

14. MOBILE
COMPUTING:• Mobile computing is a generic term describing one’s ability to use
technology while moving, as opposed to portable computers, which are only
practical for use while deployed in a stationary configuration.
• Many types of mobile computers have been introduced in 1990s, including
the PDAs and smart phones.
UTILITIES: utilities is a program that performs a very specific task usually
related to managing system resources.
WORD PROCESSORS : it is a program that enables you to perform word
processing functions. It is used to create, edit ,print the documents .
Basic capabilities of word processors:
Insert , delete text
Cut, copy and paste

15. Spreadsheets :
• It is a table of values arranged in a rows and columns.
• Each value can have a predefined relationship to the other values.
Characteristics of a spreadsheet:
• Table format
• Recalculation
• Data forms
• Presentation
• Storage and retrieval
• Standard format
• Image processors:
• Image processors or graphics program enable you to create,
edit, manipulate, add special efforts, view, print, and save

16. DATABASE
MANAGEMENT SYSTEM
INFORMATION
Information is refined data. Accuracy, timeliness, and
relevancy are the three key attributes of information. Accuracy
means that the information is free from mistakes and errors.
Timeliness means getting the information to the recipients
within the needed time frame. Relevancy means the use of a
piece of information for a particular person.
Data management is a discipline that focuses on the proper

17. ADVANTAGES
• Redundancy can be reduced
• Inconsistency can be avoided
• Data can be shared
• Standards can be enforced
• Security restrictions can be applied
• Integrity can be maintained
• Conflicting requirements can be balanced
ORGANIZATION OF A DATABASE:
A database consists of four elements – data, relationships, constraints and schema.

18. BENEFITS OF
USING A DBMS:
• The DBMS helps make data management much
more efficient and effective than it was before
the DBMS became a reality.
• The DBMS contains a query language that
makes it possible to produce quick answer to ad
hoc queries.
• Wider access to well-managed data promotes an
integrated view of the organization’s operations.
FUNCTIONS OF DBMS:
• Transaction management
• Concurrency control
• Recovery management

19. Database architecture:
database architecture defines the manner in which the components of
a database are organized and integrated.
ANSI/SPARC architecture:
A commonly used view of data approach is the three level architecture
suggested by american national standards institute/standards planning and
requirements committee(ANSI/SPARC).
Structural description: the structural description is somewhat
analogous to a record definition. It include name,type,null concept and key
fields.
Linkage description: the linkage description indicates the connections
between the files comprising the database.

20. External or logical schema:
The external schema is the view that the individual user of the
database has. This view is often a restricted view of the database
and the same database may provide a number of different views for
different classes of users. At the highest level we have multiple
external schemas that correspond to different views of data.
Conceptual schema:
The conceptual schema is the information model of the enterprise and
contains the views of the whole enterprise without any concern for the
physical implementation. The conceptual level provides both the mapping
and the desired independence between the external and internal levels. It
supports each external view, in that any data available to a user must be

21. Internal or physical schema:
At the lowest level certain physical components
organize and store the raw data. The physical
schema typically has parameters that can be tuned
for optimal performance under the access patterns
of a particular application.the database designer
may want to specify these parameters.
Database users and ANSI/SPARC
architecture:
1. Application programmers: application programmers
are individuals who use the database to create reports
based on queries.
2. Database designers: the database designer must

22. Database languages:
Data definition language: the ddl is a machine and DBMS
independent language used to create the conceptual and external schemas.
Storage definition language: the SDL is used to specify the
internal schema.SDL is used where a clear separation is maintained b/w the
conceptual and physical levels.
View definition language: where a clear separation b/w the
conceptual and physical schemas are maintained,the DDL is used to define
the conceptual and the SDL to specify the internal schema.
Data manipulation language: the DML is used to query the
database. Application programmers use a DML to retrieve or modify data

23. Information modeling:
The objective of information modeling is to identify the major entities
that are fundamental in an application and model them in a target
database schema model.
Design constraints:
Limits are called constraints in the database.there are many kinds of
database constraints.
Structural constraints: the structure of the information within the database
gives an ideas about entities in the database.
Type constraints: a type constraints limits the application to only one
representation of information for an entity’s attribute.
Range constraints: it limit the values an attributes can take. It refers to the

24. Relationship constraints: these constraints represent
relationships on values between entities.
Temporal constraints: these constraints indicate the time
period for which some information is valid.
Relational database management system
and structured query language:-
A relational database is a database that maintains a set of separate,
related files, but combines data elements from the files for queries and
reports when required.
Structured query language(SQL):
SQL is the standard command set used to communicate with the
relational database management system. Sql is the only language that
the RDBMS understands.

25. • Sql enables the end users and system personnel
to deal with a number of database management
system where it is available.
• Applications written in sql can be easily ported
across system.
• Sql as a language is independent of the way it is
implemented internally.
• The results to be excepted are well defined.
• Sql is not merely a query language.
Types of sql commands:
Querying data
Updating, inserting, deleting data
Creating, modifying, deleting database objects

26. Distributed database:
A distributed database is a database physically stored in two or
more computer system. It manage and controls the entire database
as a single collection of data.
Active databases:
• Active database system support mechanisms that enables them to
respond automatically to events that are taking place either inside or
outside the database system itself.
• It support the preceding application by moving the reactive behavior
from the application into the DBMS.
• Active databases are thus able to monitor and react to specific
circumstances of relevance to an application.
Deductive databases:

27. • Database technologies has evolved in order to effectively and efficiently
organize, manage and maintain large volumes of increasingly complex data
reliably in various memory devices.
Parallel databases:
• Parallel processing divides a large task into many smaller tasks and
executes the smaller tasks concurrently on several nodes.
• The larger task completes more quickly .
• A node is a separate processor, often on a separate machine.
• Multiple processor however can reside on a single machine.
• Some tasks can be effectively divided and thus are good candidates for
parallel processing.

28. Multidimensional databases:
• A multidimensional databases is a type of database that is
optimized for data warehouses and online analytical processing
applications.
• Multidimensional database are frequently created using input
from existing relational databases.
• A multidimensional database or a multidimensional relational
database management system implies the ability to rapidly
process the data in the database so that answers can be
generated quickly.
Temporal databases:
• Economical data is frequency time dependent
• More sophisticated analysis might want to correlate interest rate

29. • Our everyday life is vary often influenced by timetables for buses, trains,
flights, university lectures and even cinema, theatre or tv programs.
• Medical diagnosis often draws conclusion from patients history from the
evolution illness.
Spatial databases:
A spatial database is a database that is optimized to store and query
data related to object in space, including points, lines and polygons.
Multimedia databases:
Multimedia database provide features that allows users to store and
query different types of multimedia information like images, video clips,
audio clips and documents.
Web databases:
It designed to handle the storage and retrieval of constantly updated
information, they let you incorporate data that changes a lot, such as e-