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2.Different types of os?

Ans:

1)Single user, single tasking operating system: - ms dos

Dese are those operating systems in which a single user can do a single

task at a time .

Example is MS DOS. In Microsoft DOS only one program can beexecuted by a user at a time.

2) Single user multi tasking operating system Microsoft windows

Dese are those operating systems in which a single user can do multiple

task /operation at a time .example of dis is Microsoft Windows .In

Windows only one user can log in at a time but he can do can do many

tasks at a time.

3) Multi user, multi tasking - In this more than one user can log in at atime and they can do as many tasks they want.

Linux is an example of such operating system. This is the maindifference

between a windows and Linuxoperating system.

4) Real time operating systems these are those operating systems

which are used in real time applications like embedded systems, robots,

automobile engine controllers etc.

Windows CE is an example for real time operating system.

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Real-time OS: This kind of OS controls machinery, industrial equipment and scientific

instruments. Its main purpose is to ensure that an operation executes in exactly the same way, in

the same amount of time, every time it happens.

Ques3. THE DIFFERENCES BETWEEN MICROPROCESSOR AND

MICROCONTROLLER?

Ans:

Comparison of Microcontroller and Microprocessor

Microcontroller

3. Separate memory to store program and data..

Microprocessor

4. Program and data are stored in same memory.

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a.microprocessor doesnt have internal ram and rom where as microcontroller has

them.

b.microprocessor doesnt have input and output ports where as microcontroller ha them.

c.microprocessor is used for processing data where as microcontroller is used to

control

QUES4. . Difference between Interpretor and Compilor.

ANS:http://www.engineersgarage.com/contribution/difference-between-compiler-and-

interpreter

1.A compiler converts the entire program into executable code before running, when

running the program only the executable version of the code is running.

An interpreter converts the code during run time.

2. A complier converts the high level instruction into machine language while aninterpreter converts the high level instruction into an intermediate form.3. List of errors is created by the compiler after the compilation process while aninterpreter stops translating after the first error.4.ex of compiler: C compiler

Ex of interpreter: Basic5 .compiler: intermediate object code is generated.

Interpreter: no intermediate object code is generated.

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QUES5. What is a cross compiler?

ANS:Acompilerthat runs on one computer but producesobject codefor a different type of

computer. Cross compilers are used to generatesoftwarethat can run on computers with a

new architecture or on special-purpose devices that cannot host their own compilers.

Ques 6. What is Memory mapped IO?

Ans:The use of the same instructions andbusto communicate with bothmain

memoryandinput/outputdevices.

It is a reserved memory.Some parts of RAM is reserved by os for executing input output

instruction for memory mapping io.

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QUES 7: What is a semaphore?

ANS: A semaphore is used to avoid deadlocks. (deadlock means application hanging

or process hanging.)The three basic functionalities associated with semaphores are set,check and wait until it clears to set it again. |

A semaphore is a variable. There are 2 types of semaphores:

Binary semaphoresCounting semaphores

Binary semaphores have 2 methods associated with it. (up, down / lock, unlock)Binary semaphores can take only 2 values (0/1). They are used to acquire locks. Whena resource is available, the process in charge set the semaphore to 1 else 0.

Counting Semaphore may have value to be greater than one, typically used to allocateresources from a pool of identical resources.

Ques 8. . What are system calls?

Ans: Incomputing, a system call is how a program requests a service fromanoperating system'skernel. Services likes (e.g. accessing the hard disk), creatingand executing new processes. System calls provide an essential interface between aprocess and the operating system.

What is the purpose of system calls?

Ans:System calls allow user-level processes to request services of the operating system.

Types of system call:

1. File management 4. I/O device management2. Interprocess communication 5. Information maintenance

3. Process management

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Ques9. One hour reading on File Systems and Process

management systems.

Ans: A file system is a method of organizing files on physical media, such as hard disks, CD's, and flash drives. Inthe Microsoft Windows family of operating systems, users are presented with several different choices of file

systems when formatting such media. These choices depend on the type of media involved and the situations inwhich the media is being formatted. The two most common file systems in Windows are as follows:

NTFS

FAT

The NTFS file system

NTFS (short for New Technology File System) is a modern, well -formed file system that is most commonly used by

Windows 2000, XP, and Vista. It has feature-rich, yet simple organization that allows it to be used on very large

volumes.

NTFS has the following properties:

NTFS partitions can extend up to 16EB (about 16 million TB).

Files stored to NTFS partitions can be as large as the partition.

NTFS partitions occasionally become fragmentented and should be defragmented every one to two

months.

NTFS partitions can be read from and written to by Windows and Linux systems and, can only be read

from by Mac OS X systems (by default). Mac OS X,

The FAT file systemThe FAT (short for File Allocation Table) file system is a general purpose file system that is compatiblewith all major operating systems (Windows, Mac OS X, and Linux/Unix). It has relatively simple technicalunderpinnings, and was the default file system for all Windows operating systems prior to Windows 2000.

Because of its overly simplistic structure, FAT suffers from issues such as over-fragmentation, filecorruption, and limits to file names and size.The FAT file system has the following properties:

FAT partitions cannot extend beyond 2TB.

Files stored to a FAT partition cannot exceed 4GB.

FAT partitions need to be defragmented often to maintain reasonable performance.

FAT partitions larger than 32GB are generally not recommended

Process Management A process is a program in a state of execution. It is a unit of work for the operating system. Aprocess can be created, executed, and stopped. In contrast, a program is always static and doesnot have any state. A program may have two or more processes running. A process and a

program are, thus, two different entities. To accomplish a task, a process needs to have access to different system resources like I/Odevices, CPU, memory etc. The process management function of an operating system handlesallocation of resources to the processes in an efficient manner. The allocation of resourcesrequired by a process is made during process creation and process execution.

A process changes its state as it is executed. The various states that a process changesduring execution are as follows (Figure 7.6):

Figure 7.6. Process states

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o Newprocess is in a new state when it is created,

o Readyprocess is in ready state when it is waiting for a processor,

o Runningprocess is in running state if processor is executing the process,

o Waitingprocess is in waiting state when it waits for some event to happen (I/O etc),

and

o Terminatedprocess that has finished execution is in terminated state. A system consists of collection of processes(1) system process that execute system code,and (2) user process that execute user code. OS mainly handles the execution of user code,though it may also handle various system processes.

The concurrent execution of the process requires process synchronization and CPU scheduling.

Ques10. . os layers or osi models.

Ques11. Difference between 32 bit and 64 bit operating

systems.

Ans 32 bit 64 bit

1. It has 512 MB of RAM. 1.it has 1gb of RAM

2. IT can acess upto 4 GB of RAM. 2.IT can acess upto 128 GB

of RAM.3. In 32 bit os there is only one program file. 3. in 64 bit os there are 2 prgrm files

a.)prgrm files b.)program files(x86).

4. in 64 bit os all 32 bit applications

stored in prgrmfile x86 in

wow6432node.

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Kernel Patch

Protection

(PatchGuard)

This feature is

not available in

32-bit versions

of Windows

Vista.

This feature is available in 64-bit versions of

Windows Vista. Kernel Patch Protection helps

prevent a malicious program from updating the

Windows Vista kernel. This feature works by

helping to prevent a kernel-mode driver from

extending or replacing other kernel services. Also,

this feature helps prevent third-party programs

from updating (patching) any part of the kernel.

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Data structure and data base

http://www.fresherventure.net/frequently-asked-data-structures-interview-questions-and-

answers/

Linked list:

Define Linked Lists

Linked list is a collection of nodes or series that are linked to one another with the

help of pointer.

And each node consisit of 2 parts.

Data or info part: contains d value or info of the elements.

Link or pointer part: contains the adress of the next node.

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3. State the different types of linked lists

The different types of linked list include singly linked list, doubly linked list and

circular linked list.

Singly linked list: In this nodes are connected to each other with the help of single link.

Nodes keep records of the sucessor nodes only.

Circular linked list: In this type of list nodes are connected by single link nd the last node point

backs to the frst node.

Doubly linked list: In this type of linked list nodes are connected by double links.and each node

keeps record of the succesor node as well as predeccessor node.

Circular doubly linked list: nodes are connected by double links and last nodes points back to

the frst node.

QUES List the basic operations carried out in a linked list

The basic operations carried out in a linked list include:

Creation of a list

Insertion of a node

Deletion of a node

Modification of a node

Traversal of the list

Q.List out the disadvantages of using a linked list

Searching a particular element in a list is difficult and time consuming

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Q.State the difference between arrays and linked lists

Arrays Linked Lists

Size of an array is fixed Size of a list is variable

It is necessary to specify the

number of elements duringdeclaration.

It is not necessary to specify the

number of elements duringdeclaration

Insertions and deletions aresomewhat difficult

Insertions and deletions are carriedout easily

It occupies less memory than alinked list for the same number of

elements

It occupies more memory

Q. Define a stack

Stack is an ordered collection of elements in which insertions and deletions are

done at one end. Which is refered as a top of the stack. Stacks are also referred (LIFO) lists.

Q. List out the basic operations that can be performed on a stack

The basic operations that can be performed on a stack are

Push operation

Pop operation

Q. State the different ways of representing expressions

The different ways of representing expressions are

Infix Notation

Prefix Notation

Postfix Notation

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Q.State the difference between stacks and linked lists

The difference between stacks and linked lists is that insertions and deletions may

occur anywhere in a linked list, but only at the top of the stack

Q. State the difference between queues and linked lists

The difference between queues and linked lists is that insertions and deletions may occur

anywhere in the linked list, but in queues insertions can be made only in the rear end and

deletions can be made only in the front end.

Searching: It is a process of checking whether a particular element is presence in the list or

not.

2 TYPES: a. linear search /sequential search b. binary search

A.)Linear search: in LS we search the particular element by comparing it with other elements

in d list lineary or one by one.

EX: 8 41 3 75 92

B.) BINARY SEARCH: IT uses divide nd conquer method in which list is divide in 2 equal parts

exactly frm the middle .nd if the middle item is = to the search item den process gets ovr othr

wise we we chk d existence of elements in either of 2 parts.

Ex: 3 7 35 75 92

Sorting: the process of arranging data/items according to dere values are called sorting.

Types:

a)insertion sort: here we r chkng the 1st

item wid 2nd

item.

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b.)selection sort: list is divided in to 2 parts frst, then select smallest elements from unsorted

list nd exchange with d element at d beginning of d unsorted data.each time d data moves to

sorted list frm unsorted list called as one sort pass.

c.) bubble sort: lst is divided into sorted and unsorted sublist.den smallest data is bubbled frm d

unsorted list to sorted list.

d.)quick sort:

DATA BASE

QUES 1. PURPOSE OF DATA BASE TESTING.

ANS:

Database testing can be done in two ways that is testing the backend

end database by inserting the values in the frontend application and

seeing whether these had been inserted correctly r not and at the

same time inserting the values in the backend database directly and

seeing them in the frontend application.

in manual database testing we will type the querry and see that the

table is giving the same result or not.

Purpose:

To chk d security of d db.

robustness of the db(how mch it can expand)

to chk the reliabiltymeans (data shld not crash nd easily bacakable)

QUES2. Type of SQL commands + Joins etc.

Ans:http://www.studytonight.com/dbms/database-normalization.php

SQL JOINS

SQL join is used to fetch data from 2 or more tables. it is used to combining columns from 2 or

more tables by using value common to both the tables.

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Ques3 . . Normalization concept:

Ans:http://www.studytonight.com/dbms/database-normalization.php

Ques 4. . Should be able to write queries.

Ans:http://www.tizag.com/sqlTutorial/sqlqueries.php

http://www.gcreddy.net/2010/03/sql-queries-examples.html#.UfaUsNKouAA