ACID properties of transaction

Transaction :-
                      A transaction is collection of operations that performs a single logical function in a database application that may lead to success or failure in operation maintaining integrity.

ACID properties of transaction :-

Atomicity :-
Transaction must be either performed full or not at all.
It will run to completion as as individual unit ,at the end of which either no change have
occurred to database or database has been changed in consistent manner .
At the end of transaction update it will be accessible to all.

Consistency :-
A correct execution of transaction must take DB from one consistent state to another,
programmer is responsible for this.
This property implies that if database was in consistent state before start of transaction ,then
at any time of termination too it must be consistent.

Independence:-
Transaction must not make its update visible to other transactions.
All actions performed by it must be independent.
This property gives transaction a measure of relative independence.

Durability:-
Once changes are committed must never be lost .
And any updating in database may not loss updates made by transaction.

SOLVE QUESTION ANSWERS ON OPERATING SYSTEM .

1.One can interface with operating system by means of -------
A) Operating system call in a program
B) Operating system commands
C) Operating system process
D) Both by operating system call and operating system commands

Answer :-  D) Both by operating system call and operating system commands

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2. Which of the following is not type of processing ?
A) Serial
B) Network
C) Batch
D) Multiprogramming

Answer :- B) Network

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3. Kernel is _____
A) A part of operating system
B) An operating system
C) A hardware
D) A register

Answer :-  A) A part of operating system

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4. UNIX operating system is based on ______
A) Language structure
B) Kernel approach
C) Virtual machine
D) Time sharing

Answer :-   B) Kernel approach

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5. A transition between two memory resident process in a memory resident process in amultiprograming system is called ______
A) Process switch
B) Mode switch
C) Transition switch
D) None of these

Answer :-    A) Process switch

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6. Round robin scheduling algorithm falls under category of _____
A) Preemptive scheduling
B) Non- preemptive scheduling
C) Sometime preemptive sometime non-preemptive
D) None of tehse
Answer :-  A) Preemptive scheduling

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7. Paging is  a _______
A) Virtual memory
B) Memory management scheme
C) Allocation of memory
D) Deadlock prevention scheme

Answer  :-    B) Memory management scheme

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8. The first version of UNIX was written by _____
A) Dennis Ritchie
B) Andrew S
C) Ken Thompson
D) None of these


Answer :- C) Ken Thompson

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9. Chaining and Indexing are the strategies of ______
A) Contiguous allocation
B) Non-contiguous allocation
C) Partition allocation
D) Static allocation

Answer :-  B) Non-contiguous allocation

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10. Wasting of memory within a partition ,due to a difference in size of a partition and of the object resident within it is called _____
A) External fragmentation
B) Internal fragmentation
C) Compaction
D) Coalescing

Answer :-   B) Internal fragmentation

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11.Which of the following is an operating system call ?
A) CREATE
B) LINK
C) SYSTEM
D) All of these

Answer :-    D) All of these

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12.The primary job as the operating  system of a computer is to
A) command resources
B) manage resources
C) provide utilities
D) be use friendly

Answer : -  B) manage resources

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13.Dirty bit for a page in a page table
A) helps avoid unnecessary writes on a paging device
B) helps maintain LRU information
C) allows only read on a page
D) none of these

Answer : -   A) helps avoid unnecessary writes on a paging device

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14. The term "operating system " means
A) a set of programme which controls computer working
B) the way a computer operator works
C) conversion of high language into machine code
D)  the way a floppy disk drive operates

Answer :-  A) a set of programme which controls computer working

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15. Windows is a/an
A) operating system
B) user interface
C) operating environment
D) programming platform

Answer :-  C) operating environment

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16. When did IBM released teh first version of its Disk Operating System (DOS) version 1.0?
A) 1981
B) 1982
C) 1983
D) 1984


Answer :- A) 1981

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