Operating System Questions in different software companies......:-)

Operating System Questions in different software companies 

·         What is MUTEX ?

·         What isthe difference between a 'thread' and a 'process'?

·         What is INODE?

·         Explain the working of Virtual Memory.

·         How does Windows NT supports Multitasking?

·         Explain the Unix Kernel.

·         What is Concurrency? Expain with example Deadlock and Starvation.

·         What are your solution strategies for "Dining Philosophers Problem" ?

·         Explain Memory Partitioning, Paging, Segmentation.

·         Explain Scheduling.

·         Operating System Security.

·         What is Semaphore?

·         Explain the following file systems : NTFS, Macintosh(HPFS), FAT .

·         What are the different process states?

·         What is Marshalling?

·         Define and explain COM?

·         What is Marshalling?

·         Difference - Loading and Linking ?

·         What are the basic functions of an operating system?

·         Explain briefly about, processor, assembler, compiler, loader, linker and the functions executed by them.

·         What are the difference phases of software development? Explain briefly?

·         Differentiate between RAM and ROM?

·         What is DRAM? In which form does it store data?

·         What is cache memory?

·         What is hard disk and what is its purpose?

·         Differentiate between Complier and Interpreter?

·         What are the different tasks of Lexical analysis?

·         What are the different functions of Syntax phase, Sheduler?

·         What are the main difference between Micro-Controller and Micro- Processor?

·         Describe different job scheduling in operating systems.

·         What is a Real-Time System ?

·         What is the difference between Hard and Soft real-time systems ?

·         What is a mission critical system ?

·         What is the important aspect of a real-time system ?

·          If two processes which shares same system memory and system clock in a distributed system, What is it called?

·         What is the state of the processor, when a process is waiting for some event to occur?

·         What do you mean by deadlock?

·         Explain the difference between microkernel and macro kernel.

·         Give an example of microkernel.

·         When would you choose bottom up methodology?

·         When would you choose top down methodology?

·         Write a small dc shell script to find number of FF in the design.

·         Why paging is used ?

·         Which is the best page replacement algorithm and Why? How much time is spent usually in each phases and why?

·         Difference between Primary storage and secondary storage?

·         What is multi tasking, multi programming, multi threading?

·         Difference between multi threading and multi tasking?

·         What is software life cycle?

·         Demand paging, page faults, replacement algorithms, thrashing, etc.

·         Explain about paged segmentation and segment paging

·         While running DOS on a PC, which command would be used to duplicate the entire diskette?

Interview Questions Asked in several Multi National Companies ........!!!!!

   Interview Questions Asked in several Multi National Companies

1) what is the difference between Interfaces and Abstract classes?
2) what is the use of interfaces and abstract classes?
3) what are the classes/interfaces available in java.io package?
4) write the code to read the contents of a file and display it on the console.
5) In which Class the toString() is defined?
6) If we call the toString() with the reference of any object, what will it return?
7) what is Serialization and where do you use it?
8) what is the difference between String,StringBuffer and StringBuilder?
9) what is the parent class of Exception and how many types of Exceptions are available in Java?
10) How can you write a userdefined exceptions and where do you use them?
11) write an example for polymorphism other than text book examples?
12) what is the difference between HashMap and HashTree?
13) write the code to insert and retrieve elements from HashMap?
14) what is the difference between Iterator and ListIterator?
15) what is the difference between Statement and PreparedStatement?
16) How PreparedStatement will be more effective and when?
17) what is a CallableStatement?
18) what is a procedure and write the code to call a procedure from the jdbc program?
19) where do the procedures store and in which format?
20) where the procedures got executed and generally where do we use them?
21) How can we write the Join Queries and what is the use of these queries?
22) what is the primary key and why do we use the primary key?
23) why do we use the relations among tables?
24) what is the difference between post and get methods?
25) write the html tag to use image as a hyperlink with the alternate message?
26) write the tag to create a radio button in HTML.
27) write any sample code that you used in javascript?
28) what are the objects that you used in javascript?
29) Explain the lifecycle of a servlet and what are scenarios in which the destroy method executes?
30) what is the difference between servlets and JSPs?
31) what are the implicit objects available in JSPs?
32) what are the methods available in JSPs?
33) Explain about the Bubble Sort Technique by taking the numbers: 2 8 4 6 3 1
34) How can you set the CLASSPATH in MyEclipse IDE?
35) How can you pass the command line arguments in MyEclipse IDE?
36) write the logic to display the tables from 1 to 20 each table upto 20 rows.
37) Apache tomcat is which type of server?

 

Maths Tricks with Numbers

Maths Tricks with Numbers

Trick 1:Quick Square Step1: If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Step2: Mulitply the first digit by itself + 1, and put 25 on the end. Step3:That is all! Step4: Ex:25 ie(2*(2+1))&25 Answer:625 Trick 2: Multiply by 5 Step1: Take any number, then divide it by 2 Step2:If the result is whole, add a 0 at the end. Step3: If it is not, ignore the remainder and add a 5 at the end. Step4: 2682 x 5 = (2682 / 2) & 5 or 0 Step5:2682 / 2 = 1341 (whole number so add 0) Step6:Ans:13410 Step7:Let’s try another:5887 x 5,2943.5 (fractional numbers (ignore remainder, add 5) Answer: 29435 Trick 3: Tough Multiplication Step1: If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer Step2:Ex:32 x 125, is the same as: 16 x 250 is the same as: 8 x 500 is the same as: 4 x 1000 = 4,000 Trick 4: Subtracting from 1,000 Step1:To subtract a large number from 1,000 you can use this basic rule: subtract all but the last number from 9, then subtract the last number from 10: Step2:Ex:1000-648 Step3: subtract 6 from 9 = 3 Step4: subtract 4 from 9 = 5 step5: subtract 8 from 10 = 2 Answer: 352

Primary information about DATABASE

                                                                         DATA BASE

It is an organized list of data (information) that can be queried to find information quickly and easily based on a chosen reference point such as a last name or a social security number.

Access is a RDBMS that you can use to store and manipulate large amounts of information.

A Relational Database is a database, which consists of Tables of related information that are linked together based on a key field.

ELEMENTS OF ACCESSES

 An access is an object-oriented program. It has the following objects.

1.Database Window

2.Tables

3.Queries

4.Forms

5.Reports

6.Macros

7.Modules

Data Type	Description
Text	It can store 255 alphanumeric characters, used for storing data
Memo	It can hold up to 64,000 characters
Number	It is used for calculations, can consist of numerical digits
Date/ Time	Stores a date or time. Consists of 8 bits
Currency	It is used for monitory values. Consists of 8 bytes.
Counter	It is numeric value that automatically increment for each record
Yes/ No	Stores Boolean values
OLE Object	Stores pictures, graphs and other binary data. Can consists of 128 MB

DATA VALIDATION

It helps to reduce the number of data entry errors, which occur when a large amount of data is being entered into a database. Access provides a basic level of data validation with the validation rule property for each field. Assuming that only local phone numbers will be entered in the field, the first step is to limit the field size to seven digits. Position the cursor in the filed size panel, and replace the field size of 50 characters with 7 characters.

Uses of MS- Accesses

It is a Relational Database. It helps us to collect information in tables. i.e. collection of rows and columns. Then we can sort it, print it or scroll through. It allows us to create forms in user-defined fashion. Apart from forms, reports are created which can include subtotals, averages, and some other computations. If we need to view data directly or depending on some condition also, queries is applied.

Queries

Ø  By using queries we can view, change and analyze data in different ways. You can also use them as the source of records for forms and reports.

Ø  You can bring together data form multiple tables and sort it in a particular order.

Ø  You can perform calculations on groups of records

Ø  You can calculate a sum, count, or another type of total and then group the results by two types of information – one down the left side of the datasheet and another across the top.

The query window is divided in to two halves. The top panel contains the list of all the fields in a table and in the bottom panel the criteria for the query are entered this panel is called the design grid. This design grid having 5 rows.

Field	Specifies the fields to be included in the query
Table	Specifies which table does the above field belong to.
Sort	Specifies the manner in which the query has to be sorted.
Show	Specifies whether to display the field or not
Criteria	Specifies the criteria of the records to be shown.

PRIMARY KEY

 Ø  It is the field, which identifies a record.  The entry done into this field is unique. It cannot be same for the two records.

Ø Primary field of one table appearing as a normal field in some another table is called a Foreign Key Field. If there is a entry in the Foreign key field then there has to exist  a corresponding entry in the primary key field.

LOGICAL OPERATORS

Ø  Logical and Logical OR operators

Ø  The AND operator is used when two criteria’s have to be entered into a single field. It returns the result only when the single field satisfies both the condition.

Ø  The OR operator is sued for matching any of the values specified in the criteria. It returns the result even if the single field satisfied any one of the criteria. 

RELATIONSHIPS IN DATABASE

In MS- Accesses Database, there are 3 types of Relations

1.One to One Relationship

2.Many to One Relationship of One to Many Relationships

3.Many to Many Relationships

FORMS

 Ø  In a table, numbers of records are displayed at a time. But if the table has many fields then it may not be possible for a user to view all of them. The screen may be too small to fit it. The user may have to scroll horizontally or vertically to view the rest of the fields / Records.

Ø  In forms the data can be displayed as per the users requirement. The records are generally displayed one at a time. The fields can be arranged as the user wants it. Pictures can be added to a form. The display and contents of the form is controlled fully by the user.

FORMS - 2

In forms there are three views

1.      Design 

2.      Data Sheet

3.      Form

The data sheet view shows many records whereas form view displays single record. You can toggle between these three views using the View Tool.

Type of the Forms

 1.The design view

2.Form wizard

3.Auto form columnar

4.Auto form tabular

5.Auto form data sheet

6.Chart wizard

7.Pivot table wizard

REPORT

The data shown in table, Query and forms are meant for displaying it on screen, but when you take out the printouts or the Hard copy it is known as Reports. In the database window the open button is replaced by the preview button, when you click the report tab. Reports can be viewed either in print preview mode or design mode. Data cannot be edited in the reports. The reports preview shows how the data will appear on taking out the  printouts.