Unit IV with Answers

Management Information System
Unit-4

1. What are the commonly used programming languages?
Programming languages are said to be higher or lower, depending on whether they
are closer to the language the computer itself uses or to the language that people use of
language. The commonly used programming languages are:
1. Machine language (First- generation language)
2. Assembly language (Second-generation language)
3. Procedural language (third-generation language)
4. Problem oriented language (Fourth-generation language)
5. Natural languages (Fifth-generation language)

2. What are the functions served by an Operating System?
Operating system perform basic tasks such as,
a) Recognizing input from the keyboard,
b) Sending output to the display screen,
c) Keeping track of files and directories on the disk,
d) Controlling peripheral devices such as disk drives and printers.
Today most Operating Systems perform the following important functions:
1. Processor management that is an assignment of processor to different tasks being
performed by the computer system.
2. Memory management that is an allocation of main memory and other storage
areas to the system programmes as well as user programmes and data.
3. Input/output management that is a co-ordination and assignment of the different
output and input device while one or more programmes are being executed.
4. File management that is the storage of file of various storage devices to another. It
also allows all files to be easily changed and modified through the use of text
editors or some other files manipulation routines.
5. Establishment and enforcement of a priority system. That is, it determines and
maintains the order in which jobs are to be executed in the computer system.
6. Automatic transition from job to job as directed by special control statements.
7. Interpretation of commands and instructions.
8. Coordination and assignment of compilers, assemblers, utility programs, and
other software to the various user of the computer system.
9. Facilities easy communication between the computer system and the computer
operator (human). It also establishes data security and integrity.

3. Write a note on Input devices?
Input devices are a means for the user to interact with the computer.
In other words, the computer receives instructions from user through the input devices.
The most common input device is the keyboard. The keyboard accepts letters, numbers,
special characters and commands from the user and transmits it to the computer. Some
other input devices are mouse, microphone, joysticks, rumble pads, racing wheels, track
balls, scanners, digital cameras, etc.

4. Write on mainframe computer system?
Mainframe computers can process several million-program instructions per second.
Large organizations rely on these room-size systems to handle large programs with lots
of data. Mainframes are mainly used by insurance companies, banks, airline and railway
reservation systems, etc. An advanced mainframe made by IBM is S/ 390.

5. Write a note on ALU?
Arithmetic-logic unit usually called the ALU performs two types of operations –
arithmetic and logical. Arithmetical operations are the fundamental mathematical
operations consisting of addition, subtraction, multiplication and division. Logical
operations consist of comparisons. That is, two pieces of data are compared to see
whether one is equal to, less than, or greater than the other.

6. Write a short note on output devices?
The computer communicates with the user via the output devices. The function of the
output device is to present the processed data to the user. The common output devices are
monitors and printers. The computer sends information to the monitor when the user only
wants to see them. It sends the output to the printer when the user needs a paper copy.
Speakers are the output devices used for producing sound. There are some devices such
as touch screens, modems, etc, that act as both input and output devices.

7. Explain what do you mean by Data Encryption?
For highly sensitive data such as company financial data, Data Encryption can be
used. Encryption is the coding or scrambling of data so that humans cannot read them.
Some DBMS products include encryption routines that automatically encode sensitive
data when they are stored or transmitted over communications channels. For e.g.,
encryption is commonly used in electronic funds transfer (EFT) systems. Any systems
that provide encryption facilities must also provide complementary routines for decoding
the data. These decoding routines must be protected by adequate security, or else the
advantages of encryption are lost, and they also require significant computing resources.

8. What are the different types of DBMS?
Most modern information systems utilize database technologies, either database
management systems or data warehouse systems, for data storage and retrieval. Each type
of database technology allows different types of access paths. So, the process of choosing
the appropriate type of DBMS or data warehousing technology is one of the matching the
needed access paths with the capabilities of the database technology. The different types
of DBMS are,
a) Hierarchical database model
b) Network database model
c) Relational database model
d) Object-oriented database model
e) Multidimensional database model

9. Explain data mining.
Data mining is knowledge discovery using a sophisticated blend of techniques from
traditional statistics, artificial intelligence, and computer graphics.
The goals are,
1. To explain some observed event or condition, such as why sales of pickup trucks
have increased in Colorado.
2. Confirmatory: to confirm a hypothesis, whether two-income families are more
likely to buy medical coverage than single-income families.
3. To analyze data for new or unexpected relationships, such as what spending
patterns are likely to accompany credit card fraud.

10. Write a short note on Data Base Query Language?
Query languages allow people who are not programmers to search a database
using certain selection commands. Query languages, for e.g., are used by airline or
railway reservations personnel needing ticket information. Examples of query languages
are QBE, SQL, HAL, etc. query-by-example (QBE) is the most widely available direct-
manipulation database query language. As a direct manipulation database query
language, it is easy to learn for a wide variety of people wanting to make inquiries against
database.

11. Write a note on CASE?
CASE stands for Computer-aided software engineering. It is a software tool that
provides automated support for some portion of the systems development process.

12. Define DBMS?
Data base management system defined as commercial software (occasionally,
hardware and firmware) system used to define, create, maintain, and provide controlled
access to the database and also to the repository.

13. What is Data Dictionary?
Data Dictionary is a repository of information about a database which documents
data elements of a database. RDBMS store database definition information’s in system-
created tables; we can consider these system tables as a data dictionary.A data
dictionary, as defined in the IBM Dictionary of Computing, is a "centralized repository
of information about data such as meaning, relationships to other data, origin, usage, and
format. The term may have one of several closely related meanings pertaining to
databases and database management systems (DBMS):

• A document describing a database or collection of databases
• An integral component of a DBMS that is required to determine its structure
• A piece of middleware that extends or supplants the native data dictionary of a
DBMS

14. What is System Software?
System software is closely related to, but distinct from operating system. It is a
computer software that provides the infrastructure over operating system which programs
can operate, i.e. it allows application programs to perform different task on the computer.
Operating systems, such as Microsoft Windows NT, Mac OS X or Linux, builds a virtual
machine for the system software what they can use. System software is software that
basically allows the user to work. Without the system software the computer cannot do
complex tasks. In contrast to system software, software that allows you to do things like
create text documents, play games, listen to music, or surf the web is called software. In
general, application programs are software that enables the end-user to perform specific,
productive tasks, such as word processing or image manipulation. System software
performs tasks like transferring data from memory to disk, or rendering text into a display
device.

15. Describe the various types of Printers?
Printers are routinely classified by the underlying print technology they employ
numerous such technologies have been developed over the years. The choice of print
engine has a substantial effect on what jobs a printer is suitable for, as different
technologies are capable of different levels of image/text quality, print speed, low cost,
noise; in addition, some technologies are inappropriate for certain types of physical
media (such as carbon paper or transparencies).

• Modern print technology:
The following printing technologies are routinely found in modern printers:

• Toner-based printers:

Toner-based printers work using the Xerographic principle that is used in most
photocopiers: by adhering toner to a light-sensitive print drum, then using static
electricity to transfer the toner to the printing medium to which it is fused with heat and
pressure. The most common type of toner-based printer is the laser printer, which uses
precision lasers to cause toner adherence. Laser printers are known for high quality
prints, good print speed, and a low (Black and White) cost-per-copy. They are the most
common printer for many general-purpose office applications, but are much less common
as consumer printers due to their high initial cost — although this cost is dropping. Laser
printers are available in both color and monochrome varieties.

• Liquid inkjet printers
Inkjet printers: Inkjet printers operate by propelling variably-sized droplets of
liquid or molten material (ink) onto almost any sized page. They are the most
common type of computer printer for the general consumer.
• Solid ink printers: Solid Ink printers, also known as phase-change printers, are a
type of thermal transfer printer. They use solid sticks of CMYK colored ink
(similar in consistency to candle wax), which are melted and fed into a piezo
crystal operated print-head. The print head sprays the ink on a rotating, oil coated

drum. The paper then passes over the print drum, at which time the image is
transferred, or transfixed, to the page.
• Dye-sublimation printers: A dye-sublimation printer (or dye-sub printer) is a
printer which employs a printing process that uses heat to transfer dye to a
medium such as a plastic card, paper or canvas. The process is usually to lay one
color at a time using a ribbon that has color panels. Dye-sub printers are intended
primarily for high-quality color applications, including color photography; and are
less well-suited for text. While once the province of high-end print shops, dye-
sublimation printers are now increasingly used as dedicated consumer photo
printers.

Inkless printers

• Thermal printers:

Thermal printers work by selectively heating regions of special heat-sensitive
paper. Monochrome thermal printers are used in cash registers, ATMs, gasoline
dispensers and some older inexpensive fax machines. Colors can be achieved with
special papers and different temperatures and heating rates for different colors. One
example is the ZINK technology.

• UV printers

Xerox is working on an inkless printer which will use a special reusable paper
coated with a few micrometers of UV light sensitive chemicals. The printer will use a
special UV light bar which will be able to write and erase the paper. As of early 2007 this
technology is still in development and the text on the printed pages can only last between
16-24 hours before fading.

Dot-matrix printers

In the general sense many printers rely on a matrix of pixels, or dots, that together
form the larger image. However, the term dot matrix printer is specifically used for
impact printers that use a matrix of small pins to create precise dots. The advantage of
dot-matrix over other impact printers is that they can produce graphical images in
addition to text; however the text is generally of poorer quality than impact printers that
use letterforms (type).

Other printers

A number of other sorts of printers are important for historical reasons, or for special
purpose uses:

• Digital minilab (photographic paper)
• Electrolytic printers
• Spark printer

• barcode printer multiple technologies, including: thermal printing, inkjet printing,
and laser printing barcodes
• Billboard / sign paint spray printers
• Laser etching (product packaging) industrial printers

16. Explain in detail about database administrator?

A database administrator (DBA) is a person responsible for the design,
implementation, maintenance and repair of an organization's database. They are also
known by the titles Database Coordinator or Database Programmer, and is closely
related to the Database Analyst, Database Modeler, Programmer Analyst, and Systems
Manager. The role includes the development and design of database strategies,
monitoring and improving database performance and capacity, and planning for future
expansion requirements. They may also plan, co-ordinate and implement security
measures to safeguard the database. Employing organizations may require that a
database administrator have a certification or degree for database systems (for example,
the Microsoft Certified Database Administrator).
Duties

The duties of a database administrator vary depending on job description, corporate
and Information Technology (IT) policies and the technical features and capabilities of
the DBMS being administered. They include disaster recovery (backups and testing of
backups), performance analysis and tuning, data dictionary maintenance, and database
design.

Roles of the DBA include:

• Installation of new software — it is the job of the DBA to install new versions of
DBMS software, application software, and other software related to DBMS
administration. It is important that the DBA or other IS staff members test new
software before it is moved into a production environment.

• Configuration of hardware and software with the system administrator — in many
cases the system software can only be accessed by the system administrator. In
this case, the DBA works closely with the system administrator to perform
software installations, and to configure hardware and software so that it functions
optimally with the DBMS.

• Security administration — one of the main duties of the DBA is to monitor and
administer DBMS security. This involves adding and removing users,
administering quotas, auditing, and checking for security problems.

• Data analysis — The DBA analyzes data stored in the database and makes
recommendations relating to performance and efficiency of that data storage. This

includes the effective use of indexes, enabling "Parallel Query" execution, or
other DBMS specific features.

• Database design (preliminary) — The DBA can be involved at the preliminary
database-design stages, eliminating many problems that might occur. The DBA
knows the DBMS and system, can point out potential problems, and can help the
development team with special performance considerations.

• Data modeling and optimization — by modeling the data, it is possible to
optimize the system layouts to take the most advantage of the I/O subsystem.

• Responsible for the administration of existing enterprise databases and the
analysis, design, and creation of new databases.
o Data modeling, database optimization, understanding and implementation
of schemas, and the ability to interpret and write complex Structured
Query Language (SQL) queries.
o Proactively monitor systems for optimum performance and capacity
constraints.
o Establish standards and best practices for SQL.
o Interact with and coach developers in SQL scripting.

17. What are the advantages of database approach?

Following are the advantages of database:
- Reduction in data redundancy
- Increased consistency
- More data integrity
- Independence from applications programs
- Improvement in data access by using host and query languages
- Data is more secure.
- Reduction in data entry, storage, and retrieval cost

18. What are the disadvantages of a database?
Following are the disadvantages of database:

- They are complex and difficult to use.
- Time-consuming to design
- Start-up costs regarding hardware and software
- A Damage to database will affect all application programs
- Extensive conversion costs
- Training required for all programmers and users

19. What is an operating system?
The operating system is the core software component of your computer. It performs
many functions and is, in very basic terms, an interface between your computer and the
outside world. In the section about hardware, a computer is described as consisting of
several component parts including your monitor, keyboard, mouse, and other parts. The
operating system provides an interface to these parts using what is referred to as
"drivers". This is why sometimes when you install a new printer or other piece of
hardware, your system will ask you to install more software called a driver.

20. Write in detail on operating system?

The operating system is the core software component of your computer. It performs
many functions and is, in very basic terms, an interface between your computer and the
outside world The 1960’s definition of an operating system is “the software that
controls the hardware”. However, today, due to microcode we need a better definition.
We see an operating system as the programs that make the hardware useable. In brief,
an operating system is the set of programs that controls a computer. Some examples of
operating systems are UNIX, Mach, MS-DOS, MS-Windows, Windows/NT, Chicago,
OS/2, MacOS, VMS, MVS, and VM.Controlling the computer involves software at
several levels. We will differentiate kernel services, library services, and application-
level services, all of which are part of the operating system.

Operating system concerns:

• System crashes and instabilities - These can happen due to a software bug
typically in the operating system, although computer programs being run on the
operating system can make the system more unstable or may even crash the
system by themselves. This varies depending on the type of operating system. A
system crash is the act of a system freezing and becoming unresponsive which
would cause the user to need to reboot.
• Security flaws - Some software errors leave a door open for the system to be
broken into by unauthorized intruders. As these flaws are discovered,
unauthorized intruders may try to use these to gain illegal access to your system.
Patching these flaws often will help keep your computer system secure. How this
is done will be explained later.
• Sometimes errors in the operating system will cause the computer not to work
correctly with some peripheral devices such as printers.

Operating System Types

There are many types of operating systems. The most common is the Microsoft suite of
operating systems. They include from most recent to the oldest:

• Windows XP Professional Edition - A version used by many businesses on
workstations. It has the ability to become a member of a corporate domain.

• Windows XP Home Edition - A lower cost version of Windows XP which is for
home use only and should not be used at a business.
• Windows 2000 - A better version of the Windows NT operating system which
works well both at home and as a workstation at a business. It includes
technologies which allow hardware to be automatically detected and other
enhancements over Windows NT.
• Windows ME - An upgraded version from windows 98 but it has been
historically plagued with programming errors which may be frustrating for home
users.
• Windows 98 - This was produced in two main versions. The first Windows 98
version was plagued with programming errors but the Windows 98 Second
Edition which came out later was much better with many errors resolved.
• Windows NT - A version of Windows made specifically for businesses offering
better control over workstation capabilities to help network administrators.
• Windows 95 - The first version of Windows after the older Windows 3.x versions
offering a better interface and better library functions for programs.

Objectives of Operating Systems

Modern Operating systems generally have following three major goals. Operating
systems generally accomplish these goals by running processes in low privilege and
providing service calls that invoke the operating system kernel in high-privilege state.

• To hide details of hardware by creating abstraction
an abstraction is software that hides lower level details and provides a set of
higher-level functions. An operating system transforms the physical world of
devices, instructions, memory, and time into virtual world that is the result of
abstractions built by the operating system. There are several reasons for
abstraction.
First, the code needed to control peripheral devices is not standardized. Operating
systems provide subroutines called device drivers that perform operations on
behalf of programs for example, input/output operations.
Second, the operating system introduces new functions as it abstracts the
hardware. For instance, operating system introduces the file abstraction so that
programs do not have to deal with disks.
Third, the operating system transforms the computer hardware into multiple
virtual computers, each belonging to a different program. Each program that is
running is called a process. Each process views the hardware through the lens of
abstraction.
Fourth, the operating system can enforce security through abstraction.

• To allocate resources to processes (Manage resources)
An operating system controls how processes (the active agents) may access
resources (passive entities).

• Provide a pleasant and effective user interface
The user interacts with the operating systems through the user interface and
usually interested in the “look and feel” of the operating system. The most
important components of the user interface are the command interpreter, the file
system, on-line help, and application integration. The recent trend has been
toward increasingly integrated graphical user interfaces that encompass the
activities of multiple processes on networks of computers

Other Operating System Functions

The operating system provides for several other functions including:

• System tools (programs) used to monitor computer performance, debug problems,
or maintain parts of the system.
• A set of libraries or functions which programs may use to perform specific tasks
especially relating to interfacing with computer system components.

The operating system makes these interfacing functions along with its other functions
operate smoothly and these functions are mostly transparent to the user.

21. Write about groupware?
Groupware refers to programs that help people work together collectively while
located remotely from each other. Programs that enable real time collaboration are
called synchronous groupware. Groupware services can include the sharing of
calendars, collective writing, e-mail handling, shared database access, electronic
meetings with each person able to see and display information to others, and other
activities. Sometimes called collaborative software, groupware is an integral component
of a field of study known as Computer-Supported Cooperative Work or CSCW.
Groupware is often broken down into categories describing whether or not work group
members collaborate in real time (synchronous groupware and asynchronous
groupware). Some product examples of groupware include Lotus Notes and Microsoft
Exchange, both of which facilitates calendar sharing, e-mail handling, and the
replication of files across a distributed system so that all users can view the same
information. Electronic "face-to-face" meetings are facilitated by CU-SeeMe and
Microsoft NetMeeting.

22. Give short notes on CRT screen?

The cathode ray tube (CRT) is a vacuum tube containing an electron gun (a
source of electrons) and a fluorescent screen, with internal or external means to
accelerate and deflect the electron beam, used to create images in the form of light
emitted from the fluorescent screen. The image may represent electrical waveforms
(oscilloscope), pictures (television, computer monitor), radar targets and others. The
CRT uses an evacuated glass envelope which is large, deep, heavy, and relatively
fragile. Display technologies without these disadvantages, such as flat plasma screens,

liquid crystal displays, DLP, OLED displays have replaced CRTs in many applications
and are becoming increasingly common as costs decline.

23. Different types of software’s?

Computer software:

Computer software, or just software is a general term used to describe the role that
computer programs, procedures and documentation play in a computer system.[1]

The term includes:

• Application software, such as word processors which perform productive tasks for
users.
• Firmware, which is software programmed resident to electrically programmable
memory devices on board main boards or other types of integrated hardware
carriers.
• Middleware, which controls and co-ordinates distributed systems.
• System software such as operating systems, which interface with hardware to
provide the necessary services for application software.
• Software testing is a domain dependent of development and programming.
Software testing consists of various methods to test and declare a software
product fit before it can be launched for use by either an individual or a group.
• Test ware, which is an umbrella term or container term for all utilities and
application software that serve in combination for testing a software package but
not necessarily may optionally contribute to operational purposes. As such, test
ware is not a standing configuration but merely a working environment for
application software or subsets thereof.

Software includes things such as websites, programs or video games, that are coded by
programming languages like C or C++.

Types of software

A layer structure showing where Operating System is located on generally used software
systems on desktops

Practical computer systems divide software systems into three major classes- system
software, programming software and application software, although the distinction is
arbitrary, and often blurred.

System software:

System software helps run the computer hardware and computer system. It includes a
combination of the following:

• device drivers
• operating systems
• servers
• utilities
• windowing systems

The purpose of systems software is to unburden the applications programmer from the
often complex details of the particular computer being used, including such accessories
as communications devices, printers, device readers, displays and keyboards, and also to
partition the computer's resources such as memory and processor time in a safe and stable
manner.

Programming software:

Programming software usually provides tools to assist a programmer in writing computer
programs, and software using different programming languages in a more convenient
way. The tools include:

• compilers
• debuggers
• interpreters
• linkers
• text editors

An Integrated development environment (IDE) is a single application that attempts to
manage all these functions.

Application software:

Application software allows end users to accomplish one or more specific (not directly
computer development related) tasks. Typical applications include:

• industrial automation
• business software
• computer games
• quantum chemistry and solid state physics software
• telecommunications (i.e., the internet and everything that flows on it)
• databases
• educational software
• medical software
• military software
• molecular modeling software
• image editing
• spreadsheet
• Word processing
• Decision making software

24. Define statistical packages?

A statistical package is a suite of computer programs that are specialized for
statistical analysis. It enables people to obtain the results of standard statistical
procedures and statistical significance tests, without requiring low-level numerical
programming. Most statistical packages also provide facilities for data management

List of statistical packages:

• SigmaXL - add-on to Microsoft Excel for graphical and statistical analysis
• SPC XL - add-on to Microsoft Excel for general statistics
• StatEL - add-on to Microsoft Excel (Windows and Mac OS X) for general
statistics, biomedical and data analysis specially developed in a didactic way for
all users of statistics, regardless of their skill level.
• SUDAAN - add-on to SAS and SPSS for statistical surveys
• Total Access Statistics - add-on to Microsoft Access for statistical analysis.

25. What is a magnetic disk enumerate the various types of magnetic disks?

Magnetic storage uses different patterns of magnetization on a magnetically coated
surface to store information. Magnetic storage is non-volatile. The information is
accessed using one or more read/write heads which may contain one or more recording
transducers. A read/write head only covers a part of the surface so that the head or
medium or both must be moved relative to another in order to access data. In modern
computers, magnetic storage will take these forms:

• Magnetic disk
o Floppy disk, used for off-line storage
o Hard disk drive, used for secondary storage
• Magnetic tape data storage, used for tertiary and off-line storage

In early computers, magnetic storage was also used for primary storage in a form of
magnetic drum, or core memory, core rope memory, thin-film memory, twistor memory
or bubble memory. Also unlike today, magnetic tape was often used for secondary
storage.

Optical storage, the typical Optical disc, stores information in deformities on the surface
of a circular disc and reads this information by illuminating the surface with a laser diode
and observing the reflection. Optical disc storage is non-volatile. The deformities may be
permanent (read only media), formed once (write once media) or reversible (recordable
or read/write media). The following forms are currently in common use:

• CD, CD-ROM, DVD, BD-ROM: Read only storage, used for mass distribution of
digital information (music, video, computer programs)

• CD-R, DVD-R, DVD+R BD-R: Write once storage, used for tertiary and off-line
storage
• CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE: Slow write, fast read
storage, used for tertiary and off-line storage
• Ultra Density Optical or UDO is similar in capacity to BD-R or BD-RE and is
slow write, fast read storage used for tertiary and off-line storage.

Magneto-optical disc storage is optical disc storage where the magnetic state on a
ferromagnetic surface stores information. The information is read optically and written by
combining magnetic and optical methods. Magneto-optical disc storage is non-volatile,
sequential access, slow write, fast read storage used for tertiary and off-line storage.

26. Briefly explain the various operating system environments?

The operating system is the core software component of your computer. It
performs many functions and is, in very basic terms, an interface between your computer
and the outside world The 1960’s definition of an operating system is “the software that
controls the hardware”. However, today, due to microcode we need a better definition.
We see an operating system as the programs that make the hardware useable. In brief, an
operating system is the set of programs that controls a computer. Some examples of
operating systems are UNIX, Mach, MS-DOS, MS-Windows, Windows/NT, Chicago,
OS/2, MacOS, VMS, MVS, and VM.Controlling the computer involves software at
several levels. We will differentiate kernel services, library services, and application-
level services, all of which are part of the operating system.

The various operating system environments are discussed below in detail.

Microsoft Windows

Windows 7 is the latest stable Windows operating system.

Microsoft Windows is a family of proprietary operating systems that originated as an
add-on to the older MS-DOS operating system for the IBM PC. Modern versions are
based on the newer Windows NT kernel that was originally intended for OS/2. Windows
runs on x86, x86-64 and Itanium processors. Earlier versions also ran on the Alpha,
MIPS, Fairchild (later Intergraph) Clipper and PowerPC architectures (some work was
done to port it to the SPARC architecture).

The most widely used version of the Microsoft Windows family is Windows XP,
released on October 25, 2001.In November 2006, after more than five years of
development work, Microsoft released Windows Vista, a major new operating system
version of Microsoft Windows family which contains a large number of new features and
architectural changes. Chief amongst these are a new user interface and visual style called
Windows Aero, a number of new security features such as User Account Control, and a
few new multimedia applications such as Windows DVD Maker. A server variant based
on the same kernel, Windows Server 2008, was released in early 2008.

Windows 7 finished its development and was deemed "RTM" (Release to manufacturer)
after a test period which included an up gradable Windows 7 release candidate (for the
public); Microsoft has scoped its development of Windows 7 to a three-year timeline, and
it is to be released on October 22, 2009.

UNIX and Unix-like operating systems

Debian is a (Linux-based) UNIX-like system

Ken Thompson wrote B, mainly based on BCPL, which he used to write Unix, based
on his experience in the MULTICS project. B was replaced by C, and Unix developed
into a large, complex family of inter-related operating systems which have been
influential in every modern operating system (see History). The Unix-like family is a
diverse group of operating systems, with several major sub-categories including System
V, BSD, and Linux. The name "UNIX" is a trademark of The Open Group which licenses
it for use with any operating system that has been shown to conform to their definitions.
"Unix-like" is commonly used to refer to the large set of operating systems which
resemble the original UNIX. UNIX-like systems run on a wide variety of machine
architectures. They are used heavily for servers in business, as well as workstations in
academic and engineering environments. Free Unix variants, such as GNU, Linux and
BSD, are popular in these areas.

Mac OS X

Mac OS X Snow Leopard

Mac OS X is a line of partially proprietary, graphical operating systems developed,
marketed, and sold by Apple Inc., the latest of which is pre-loaded on all currently
shipping Macintosh computers. Mac OS X is the successor to the original Mac OS, which
had been Apple's primary operating system since 1984. Unlike its predecessor, Mac OS
X is a UNIX operating system built on technology that had been developed at NeXT
through the second half of the 1980s and up until Apple purchased the company in early
1997.The operating system was first released in 1999 as Mac OS X Server 1.0, with a
desktop-oriented version (Mac OS X v10.0) following in March 2001. Since then, six
more distinct "client" and "server" editions of Mac OS X have been released, the most
recent being Mac OS X v10.6, which was first made available on August 28, 2009.
Releases of Mac OS X are named after big cats; the current version of Mac OS X is
nicknamed "Snow Leopard”. The server edition, Mac OS X Server, is architecturally
identical to its desktop counterpart but usually runs on Apple's line of Macintosh server
hardware. Mac OS X Server includes work group management and administration
software tools that provide simplified access to key network services, including a mail
transfer agent, a Samba server, an LDAP server, a domain name server, and others.

Plan 9

Ken Thompson, Dennis Ritchie and Douglas McIlroy at Bell Labs designed and
developed the C programming language to build the operating system UNIX.
Programmers at Bell Labs went on to develop Plan 9 and Inferno, which were engineered
for modern distributed environments. Plan 9 was designed from the start to be a
networked operating system, and had graphics built-in, unlike UNIX, which added these
features to the design later. Plan 9 has yet to become as popular as UNIX derivatives, but
it has an expanding community of developers. It is currently released under the Lucent
Public License. Inferno was sold to Vita Nuova Holdings and has been released under a
GPL/MIT license.

Real-time operating systems
Main article: real-time operating system

A real-time operating system (RTOS1) is a multitasking operating system intended for
applications with fixed deadlines (real-time computing). Such applications include some
small embedded systems, automobile engine controllers, industrial robots, spacecraft,
industrial control, and some large-scale computing systems. An early example of a large-
scale real-time operating system was Transaction Processing Facility developed by
American Airlines and IBM for the System. Embedded systems that have fixed deadlines
use a real-time operating system such as VxWorks, eCos, QNX, MontaVista Linux and
RTLinux. Windows CE is a real-time operating system that shares similar APIs to
desktop Windows but shares none of desktop Windows' code base

Other

Older operating systems which are still used in niche markets include OS/2 from IBM
and Microsoft; Mac OS, the non-Unix precursor to Apple's Mac OS X; BeOS; XTS-300.
Some, most notably AmigaOS 4 and RISC OS, continue to be developed as minority
platforms for enthusiast communities and specialist applications. OpenVMS formerly
from DEC, is still under active development by Hewlett-Packard. There were a number
of operating systems for 8 bit computers - Apple's DOS (Disk Operating System) 3.2 &
3.3 for Apple II, ProDOS, UCSD, CP/M - available for various 8 and 16 bit
environments, Future OS for the Amstrad CPC6128 and 6128Plus.

27. Explain various input devices with examples?

An input device is any peripheral (piece of computer hardware equipment) used
to provide data and control signals to an information processing system (such as a
computer). Input and output devices make up the hardware interface between a
computer as a scanner or 6DOF controller.

Early devices

• Unit record equipment

• Punched card

Keyboards:

A keyboard is a human interface device which is represented as a layout of buttons. Each
button, or key, can be used to either input a linguistic character to a computer, or to call
upon a particular function of the computer. Traditional keyboards use spring-based
buttons, though newer variations employ virtual keys, or even projected keyboards.

Examples of types of keyboards include:

• Computer keyboard
• Keyer
• Chorded keyboard
• LPFK

Pointing devices:

A computer mouse

A pointing device is any human interface device that allows a user to input spatial data to
a computer. In the case of mice and touch screens, this is usually achieved by detecting
movement across a physical surface. Analog devices, such as 3D mice, joysticks, or
pointing sticks, function by reporting their angle of deflection. Movements of the
pointing device are echoed on the screen by movements of the cursor, creating a simple,
intuitive way to navigate a computer's GUI.

High-degree of freedom input devices:

Some devices allow many continuous degrees of freedom as input. These can be used as
pointing devices, but are generally used in ways that don't involve pointing to a location
in space, such as the control of a camera angle while in 3D applications. These kinds of
devices are typically used in Caves, where input that registers 6DOF is and is a very silly
because it doesn’t make sense.

Composite devices:

Imaging and Video input devices:

Video input devices are used to digitize images or video from the outside world into the
computer. The information can be stored in a multitude of formats depending on the
user's requirement.

• Webcam
• Image scanner
• Fingerprint scanner
• Barcode reader
• 3D scanner
• Laser rangefinder

Medical Imaging

o Computed tomography
o Magnetic resonance imaging
o Positron emission tomography
o Medical ultrasonography

Audio input devices:

In the fashion of video devices, audio devices are used to either capture or create sound.
In some cases, an audio output device can be used as an input device, in order to capture
produced sound.

• Microphone
• MIDI keyboard or other digital musical instrument
• Instrument to Computer cords, such as the Stealth Plug for the guitar

28. Explain the various storage devices?

As of 2009, the most commonly used data storage technologies are semiconductor,
magnetic, and optical, while paper still sees some limited usage. Some other fundamental
storage technologies have also been used in the past or are proposed for development.

Semiconductor

Semiconductor memory uses semiconductor-based integrated circuits to store
information. A semiconductor memory chip may contain millions of tiny transistors or
capacitors. Both volatile and non-volatile forms of semiconductor memory exist. In
modern computers, primary storage almost exclusively consists of dynamic volatile
semiconductor memory or dynamic random access memory. Since the turn of the
century, a type of non-volatile semiconductor memory known as flash memory has
steadily gained share as off-line storage for home computers. Non-volatile semiconductor
memory is also used for secondary storage in various advanced electronic devices and
specialized computers.

Magnetic

Magnetic storage uses different patterns of magnetization on a magnetically coated
surface to store information. Magnetic storage is non-volatile. The information is
accessed using one or more read/write heads which may contain one or more recording
transducers. A read/write head only covers a part of the surface so that the head or
medium or both must be moved relative to another in order to access data. In modern
computers, magnetic storage will take these forms:

• Magnetic disk
o Floppy disk, used for off-line storage
o Hard disk drive, used for secondary storage
• Magnetic tape data storage, used for tertiary and off-line storage

In early computers, magnetic storage was also used for primary storage in a form of
magnetic drum, or core memory, core rope memory, thin-film memory, twister memory
or bubble memory. Also unlike today, magnetic tape was often used for secondary
storage.

Optical

Optical storage, the typical Optical disc, stores information in deformities on the surface
of a circular disc and reads this information by illuminating the surface with a laser diode
and observing the reflection. Optical disc storage is non-volatile. The deformities may be
permanent (read only media), formed once (write once media) or reversible (recordable
or read/write media). The following forms are currently in common use:[11]

• CD, CD-ROM, DVD, BD-ROM: Read only storage, used for mass distribution of
digital information (music, video, computer programs)
• CD-R, DVD-R, DVD+R BD-R: Write once storage, used for tertiary and off-line
storage
• CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE: Slow write, fast read
storage, used for tertiary and off-line storage
• Ultra Density Optical or UDO is similar in capacity to BD-R or BD-RE and is
slow write, fast read storage used for tertiary and off-line storage.

Magneto-optical disc storage is optical disc storage where the magnetic state on a
ferromagnetic surface stores information. The information is read optically and written by
combining magnetic and optical methods. Magneto-optical disc storage is non-volatile,
sequential access, slow write, fast read storage used for tertiary and off-line storage.

3D optical data storage has also been proposed.

Paper

Paper data storage, typically in the form of paper tape or punched cards, has long been
used to store information for automatic processing, particularly before general-purpose
computers existed. Information was recorded by punching holes into the paper or
cardboard medium and was read mechanically (or later optically) to determine whether a
particular location on the medium was solid or contained a hole. A few technologies
allow people to make marks on paper that are easily read by machine—these are widely
used for tabulating votes and grading standardized tests. Barcodes made it possible for
any object that was to be sold or transported to have some computer readable information
securely attached to it.

Uncommon
Vacuum tube memory
A Williams’s tube used a cathode ray tube, and a Selectron tube used a large
vacuum tube to store information. These primary storage devices were short-lived
in the market, since Williams tube was unreliable and Selectron tube was
expensive.
Electro-acoustic memory
Delay line memory used sound waves in a substance such as mercury to store
information. Delay line memory was dynamic volatile, cycle sequential read/write
storage, and was used for primary storage.
Optical tape
Is a medium for optical storage generally consisting of a long and narrow strip of
plastic onto which patterns can be written and from which the patterns can be read
back. It shares some technologies with cinema film stock and optical discs, but is
compatible with neither. The motivation behind developing this technology was
the possibility of far greater storage capacities than either magnetic tape or optical
discs.
Phase-change memory
Uses different mechanical phases of Phase Change Material to store information
in an X-Y addressable matrix, and reads the information by observing the varying
electrical resistance of the material. Phase-change memory would be non-volatile,
random access read/write storage, and might be used for primary, secondary and
off-line storage. Most rewritable and many write once optical disks already use
phase change material to store information.
Holographic data storage
Stores information optically inside crystals or photopolymers. Holographic
storage can utilize the whole volume of the storage medium, unlike optical disc
storage which is limited to a small number of surface layers. Holographic storage
would be non-volatile, sequential access, and either write once or read/write
storage. It might be used for secondary and off-line storage. See Holographic
Versatile Disc (HVD).
Molecular memory

Stores information in polymers that can store electric charge. Molecular memory
might be especially suited for primary storage. The theoretical storage capacity of
molecular memory is 10 terabits per square inch. [12]

Robotic storage
Large quantities of individual magnetic tapes, and optical or magneto-optical discs may
be stored in robotic tertiary storage devices. In tape storage field they are known as tape
libraries, and in optical storage field optical jukeboxes, or optical disk libraries per
analogy. Smallest forms of either technology containing just one drive device are referred
to as autoloaders or auto changers.

29. Explain the structure of database?

Databases are stored in a single file. The two main structures of a database are
TABLES and INDEXES.

Tables are the structures that store your data in the database. Each table is
composed of a number of FIELDS, also known as COLUMNS in some database engines.
Suppose you want to store information about the users of your application: you could
create a table named USERS, with the following fields: NAME, AGE and ADDRESS.
Information about each user would be stored in what we call ROWS or RECORDS in the
database. Your database table could be represented by the image below, containing
records for 3 users:

Field names and types are defined when you create a table. But in order to create
a table you must first create the database file, of course. Database files can be created
with the created function in the Arca Xtra, or the Arca Database Browser application.
There is no need to specify a specific 3 letter extension for the database filename, but you
may specify one if you want to. The following script will create an unencrypted database
file named "my data" in the same directory of the current Director movie:

Lingo:
GDB = new (x-ray "arca")
gDB.createDB (the movie path & "my data")
JavaScript syntax:
GDB = new extra ("arca")
gDB.createDB (_movie. path + "my data")

30. What are the components of a database?
Ans.The following three items form the building blocks of a database. They store the
data that we want to save in our database. They are,
• Tables,
• Columns
• Rows
Columns
Columns are a kin to fields, that is, individual items of data that we wish to store. A
customer's name, the price of a part, the date of an invoice is all examples of columns.
They are also similar to the columns found in spreadsheets (the A, B, C etc along the
top).
Rows
Rows are akin to records as they contain data of multiple columns (like the 1, 2, 3 etc in a
spreadsheet). Unlike file records though, it is possible to extract only the columns you
want to make up a row of data. Old "records" that computers read forced the computer to
read EVERYTHING, even if you only wanted a tiny portion of the record. In databases, a
row can be made up of as many or as few columns as you want. This makes reading data
much more efficient - you fetch what you want.
Tables
A table is a logical group of columns. For example, you may have a table that stores
details of customers' names and addresses. Another table would be used to store details of
parts and yet another would be used for supplier's names and addresses.

31. Classify the System Software?

Ans. System software is closely related to, but distinct from Operating System software.
It is any computer software that provides the infrastructure over which programs can
operate, i.e. it manages and controls computer hardware so that application software can
perform. Operating systems, such as GNU, Microsoft Windows, Mac OS X or Linux, are
prominent examples of system software.

System software is software that basically allows the parts of a computer to work
together. Without the system software the computer cannot operate as a single unit. In

contrast to system software, software that allows you to do things like create text
documents, play games, listen to music, or surf the web is called application software. In
general, application programs are software that enables the end-user to perform specific,
productive tasks, such as word processing or image manipulation. System software
performs tasks like transferring data from memory to disk, or rendering text onto a
display device.

Types of system software

System software helps use the operating system and computer system. It includes
diagnostic tools, compilers, servers, windowing systems, utilities, language translator,
data communication programs, data management programs and more. The purpose of
systems software is to insulate the applications programmer as much as possible from the
details of the particular computer complex being used, especially memory and other
hardware features, and such accessory devices as communications, printers, readers,
displays, keyboards, etc.

Specific kinds of system software include:

• Loading
• Linkers
• Utility software
• Desktop environment / Graphical user interface
• Shell
• BIOS
• Hyper visors
• Boot loaders

If system software is stored on non-volatile memory such as integrated circuits, it is
usually termed firmware.

32. What are the roles of Information System Manager?

Ans. There are various expanding roles of the business application of Information System
by a manager.

1. Electronic Business and Commerce
• Internet based e-business and economic systems.
• Web- Enabled enterprise and global e-business operation and
electronic commerce on the internet, intranets, extranets and other
networks.
2. Strategic and End user support

• End user computing systems.
• Executive Information systems.
• Expert Systems.

• Strategic Information Systems.

3. Decision support

• Decision support systems.

4. Management reporting

• Management Information System.

5. Data processing

• Electronic data processing systems.

33. Design the Principles of Database.

Ans. Database design represents the rules of the Organization.

The most important aspect is to identify:

• Exactly what data to collect.
• How the various pieces of data are related.
• How long each item needs to be stored in the database.

The following are the initial steps in design process:

• Identify the exact goals of the system.
• Talk with the users to identify the basic forms & reports.
• Identify the data items to be stored.
• Design the classes (Tables) & relationships
• Identify the business constraints.
• Verify the design matches the business rules.

Designing Systems.

• Is complex & well designed system can generate enormous benefits to an
organization.
• Building a useful system requires that to understand & communicate with
the user.
• The design models also record the fundamentals features assumptions &
restrictions present in any business.

Identify user requirements

On challenging aspect of designing a system is to determine the requirements.

• A key step is to interview users & observe the operations of the firm.
• One of the most important tasks in designing a database application is to correctly
identify the data needs to be stored.
• The DBMS makes easy to organize, create & modify reports.
• These documents provide information about the basic data & operations of the
firm.

Designing system with models:

When a project is approved .you need to create a detailed business design. The business
design is a logical model of new system. It describes the business components & how
they are related.

From this design, we can develop the physical model define databases, develop
applications, & write proceed users, once the application is developed & tested it can be
implemented.

Unit IV with Answers

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Unit IV with Answers