M.E.S.

COLLEGE OF ENGINEERING, PUNE-01

T.E. (Computer Engineering)

Semester I AY 2021-2022
ORAL QUESTION BANK (SPOSL )

1. What is system programming?

Ans : System programming involves designing and writing computer programs that allow the
computer hardware to interface with the programmer and the user, leading to the effective
execution of application software on the computer system.
2. What is system software?
Ans : System software is a type of computer program that is designed to run a computer's
hardware and application programs. If we think of the computer system as a layered model,
the system software is the interface between the hardware and user applications.
3. What are the components of system programming?
Ans : Components of system programming are: 1) Loader 2) Assembler 3) Compiler 4) Macro
5) Interpreter
4. What is assembler?
Ans : The Assembler is a Software that converts an assembly language code to machine code. It
takes basic Computer commands and converts them into Binary Code that Computer’s Processor
can use to perform its Basic Operations. These instructions are assembler language or assembly
language.
5. Define a macro?

Ans : A macro name is an abbreviation, which stands for some related lines
of code. Macros are useful for the following purposes:
· To simplify and reduce the amount of repetitive coding
· To reduce errors caused by repetitive coding
· To make an assembly program more readable.

6. Difference between compiler and Interpreter?

 Ans:

7. What is role of linker?

Ans : Linker is a program in a system which helps to link a object modules of program into a
single object file. It performs the process of linking. Linking is performed at both compile
time, when the source code is translated into machine code and load time, when the program
is loaded into memory by the loader
8. What is loader ?
Ans: A loader is a system program, which takes the object code of a program as input and
prepares it for execution.
9. What is text editor?
Ans: A text editor is a tool that allows a user to create and revise documents in a computer.
10. Explain different component of text editor?
1. Ans : Line editor: In this, you can only edit one line at a time or an integral number of
lines. You cannot have a free-flowing sequence of characters. It will take care of only one
line.
Ex : Teleprinter, edlin, teco

2. Stream editors: In this type of editors, the file is treated as continuous flow or sequence of
characters instead of line numbers, which means here you can type paragraphs.
Ex : Sed editor in UNIX
3. Screen editors: In this type of editors, the user is able to see the cursor on the screen and
can make a copy, cut, paste operation easily. It is very easy to use mouse pointer.
Ex : vi, emacs, Notepad
4. Word Processor: Overcoming the limitations of screen editors, it allows one to use some
format to insert images, files, videos, use font, size, style features. It majorly focuses on
Natural language.
5. Structure Editor: Structure editor focuses on programming languages. It provides features
to write and edit source code.
Ex : Netbeans IDE, gEdit.

11. Explain the different functions of loader.

Ans: Loader Function: The loader performs the following functions:
1) Allocation
2) Linking
3) Relocation
4) Loading
Allocation:
• Allocates the space in the memory where the object program would be loaded for Execution.
• It allocates the space for program in the memory, by calculating the size of the program. This
activity is called allocation.
• In absolute loader allocation is done by the programmer and hence it is the duty of the
programmer to ensure that the programs do not get overlap.
• In reloadable loader allocation is done by the loader hence the assembler must supply the
loader the size of the program.
Linking:
• It links two or more object codes and provides the information needed to allow references
between them.
• It resolves the symbolic references (code/data) between the object modules by assigning all
the user subroutine and library subroutine addresses. This activity is called linking.
• In absolute loader linking is done by the programmer as the programmer is aware about the
runtime address of the symbols.
• In relocatable loader, linking is done by the loader and hence the assembler must supply to
the loader, the locations at which the loading is to be done.
Relocation:
• It modifies the object program by changing the certain instructions so that it can be loaded at
different address from location originally specified.
• There are some address dependent locations in the program, such address constants must be
adjusted according to allocated space, such activity done by loader is called relocation.
• In absolute Loader relocation is done by the assembler as the assembler is aware of the
starting address of the program.
• In relocatable loader, relocation is done by the loader and hence assembler must supply to
the loader the location at which relocation is to be done.
Loading:
• It brings the object program into the memory for execution.
• Finally it places all the machine instructions and data of corresponding programs and
subroutines into the memory. Thus program now becomes ready for execution, this activity is
called loading.
• In both the loaders (absolute, relocatable) Loading is done by the loader and hence the
assembler must supply to the loader the object program.
12. Explain all types of loader?
Ans: Types of Loader :-
There are eight(8) general loader schemes available. But generally main loader scheme is
four(1,2,3,4). Those are –
1. Absolute Loader.
2. Relocating Loader.
3. Direct Linking Loader.
4. Dynamic Loader.
5. Assemble – and – go or Compile – and – go loader.
6. Boot Strap Loader.
7. Linking Loader.
8. Relocation Loader.
Absolute Loader :- It is a sim placed type of loader scheme. It this scheme the loader simply
accepts the machine language code produced by assembler and place it into main memory at
the location specified by the assembler. The task of an absolute loader is virtually trivial.
Absolute loader is simply to implemented but it has several disadvantage –

First : The programmer must specify to the assembler the address in main memory where the
program is to be loaded.
Second : The programmer must remember the address of multiple sub – programs and there
performance.

Fig - Absolute Loader

Relocating Loader :- To avoid possible reassembling of all subroutines , When a single

subroutines is changed and to performed the task of allocation and linking of the programmer.
The general class of relocating loader was introduced.

An example of relocating loader is Binary Symbolic Subroutine (BSS) loader, IBM

7294, IBM 1130, GE635 are the BSS loader.
Output of a relocating loader is the object program and information about all other programs
its references. In addition ,there is relocating information has two location in this program that
need to be changed. If it is to be loaded in an arbitrary location in memory.

Direct Linking Loader :- Direct linking loader is a general relocatable loader and perhaps
the most popular loading scan presently used. It has the advantage of allowing the programmer
multiple procedure segments and multiple data segments. It has also an advantage that has
given to the programmer complete freedom in referencing data or instructions content in other
segments. This provides flexibility of inter segment referencing and accessing while at the
same time allowing independent translation of programs.

Dynamic loader :- Dynamic loader is the Persian of loader that actually intersect the “calls”
and loads the necessary procedure is called over lay super visor or simply flipper. This over all
scheme is called Dynamic Loading or Load on Call.
An advantage id Dynamic Loader is that, no over head is in corrected unless the
procedure to be called or referenced is actually used. Also the system can be dynamically re –
configured.
The major draw back is occurred due to the fact that we here postponed most of the
binding process until execution time.

Assemble – and – go or Compile – and – go loader :-

 Any method of performing the loader function is to have the assembler run in one of the part
of memory and place the machine instructions in data directly into assigned memory location.
This is a simply solution, involving mode any extra procedure. It is used by the WATFOR
FORTAN compiler and other several language processor (PL/I). Such a loading scheme is
commonly called compile – and – go and assemble – and – go loader.

Boot Strap Loader :- When a computer is first turned on or restarted a special type of
absolute loader is executed , called Boot Strap Loader. It loads the operation system into the
main memory and executes the related programs. It is added to the beginning of all object
programs that are to be loaded into and empty ideal system.

Linking Loader :- The need for linking a program with other programs assign because a
program written by a programmer or its translated version is really of a stand alone nature.
That is a program generally cannot executed on its own. Without requiring the presents of
some other programs is computer memory. The standard function must reside into the main
memory. The linking function next address of program known to each other, So that such
transfers can take place during the execution.

Relocation Loader: - Another function commonly performed by a loader is that of program

re – location. Relocation is simply moving a program from one area to another in the storage.
It referred to adjustment of address field and not to movement of a program. The task of
relocation is to add some constant value to each relative address in the segment the part of a
loader which performed relocation is called re – location loader.

13. What is input and output for pass1?

Ans : The assembler takes the same code for pass 1 and pass 2, but during pass 1 it builds the
symbol table, so it fills out the values during the next pass.

1. BULLET_X EQU 10
2. BULLET_Y EQU 15
3.
4. ldx #BULLET_X
5. ldy #BULLET_Y
6. jsr shoot
7. ....
8. shoot:
9. ...
So for example in the assembly language fragment above (6502 code), that values of
BULLET_X and BULLET_Y are known when the assembler gets to the instruction, but the
address of shoot is not known. The simplest way is for 2 passes and on the first pass, only the
current address is calculated (so ldx #BULLET_X will add 2 to PC, since it takes 2 bytes to
code), and the jsr shoot will take 3 bytes, and it saves the current pc when it gets to the
definition of the shoot label. During the next pass it the outputs the actual byte codes, there
were some assemblers that actually output jsr 0000 and then patched that value when the shoot
value is encountered.
Ouput of pass1 assembler : Multipass assembler means more than one pass is used by
assembler. Multipass assembler is used to eliminate forward references in symbol definition.
... In pass one we find out all the Symbols and Literals. And in pass two we will perform
assembling of code and the data (generating instruction and generating data).

14. What is input and output for pass2?

Ans :Input : Implement Pass-II of two pass assembler for pseudo-machine in Java using
object oriented features. The output of assignment-1 (intermediate file and symbol
table) should be input for this assignment.
Output : Pass-2 of assembler generates machine code by converting symbolic machine-
opcodes into their respective bit configuration(machine understandable form). It stores all
machine-opcodes in MOT table (op-code table) with symbolic code, their length and their bit
configuration.
15. Explain the following
1. LTORG

Ans : Use the LTORG instruction so that the assembler can collect and assemble literals into a
literal pool. A literal pool contains the literals you specify in a source module either after the
preceding LTORG instruction, or after the beginning of the source module. If a control section
has not been established, LTORG initiates an unnamed (private) control section.

2. Dc
Ans : The DC instruction causes the assembler to generate the binary representation of the
data constant you specify into a particular location in the assembled source module; this is
done at assembly time. The DC instruction's name — Define Constant — is misleading:
DC simply creates initial data in an area of the program.
3. DS
Ans : DS is called data segment register. It points to the segment of the data used by the
running program. You can point this to anywhere you want as long as it contains the desired
data. ES is called extra segment register.

16. what are types of statement in assembly?

Ans : Kinds of statements in assembly language
An assembly program contains following three kinds of statements:
1. Imperative statements: These indicate an action to be performed during execution of the
assembled program. Each imperative statement typically translates into one machine
instruction.
2. Declaration statements: The syntax of declaration statements is as follows:
[Label] DS<constant>
[Label] DC ‘<value>’
The DS statement reserves areas of memory and associates names with them. The DC
statement constructs memory words containing constants.
3. Assembler directives: These instruct the assembler to perform certain actions during the
assembly of a program. For example
START <constant> directive indicates that the first word of the target program generated by
the assembler should be placed in the memory word with address <constant>.

17. Example of Imperative statement ?

Ans : Imperative Statements :- An imperative statement is instruction in assembly program.
Every imperative statement generates one machine instruction. e.g A. ... START < constant >
:- This directive indicates that the first word of the target program will start on ROM memory
location with address < constant >
18. What is assembler directive?
Ans : Assembler directives are instructions that direct the assembler to do something. ... This
is used to set the program or register address during assembly. For example, ORG 0100h tells
the assembler to assemble all subsequent code starting at address 0100h. DS. Defines an
amount of free space.
19. Explain the following
1. EQU
Ans: EQU is used as a substitute for labels or symbols.
2. ORIGIN
Ans : The origin directive tells the assembler where to load instructions and data into
memory. The syntax of this directive is. ORIGIN < address spec > This directive
indicates that LC ( location counter ) should be set to the address given by. < address spec
>. The ORIGIN statement is useful when the target program does not consist of
consecutive memory words
3. START
Ans : This instruction starts the execution of program from location 200 and label with
START provides name for the program
4. END
Ans : The END statement is the last line in the main program and in all subroutines or
functions. Since an END statement is a non-executable statement, the program cannot branch
to an END statement.
20. Give the data structure used for Pass1 and Pass2 of assembler?

Ans: Pass 1 Data Structures

1. Input source program

2. A Location Counter (LC), used to keep track of each instruction’s location.

3. A table, the Machine-operation Table (MOT), that indicates the symbolic mnemonic, for
each instruction and its length (two, four, or six bytes)

4. A table, the Pseudo-Operation Table (POT) that indicates the symbolic mnemonic and
action to be taken for each pseudo-op in pass 1.

5. A table, the Symbol Table (ST) that is used to store each label and its corresponding value.

6. A table, the literal table (LT) that is used to store each literal encountered and its
corresponding assignment location.

7. A copy of the input to be used by pass 2.

Pass 2 Data Structures

1. Copy of source program input to pass1.

2. Location Counter (LC)

3. A table, the Machine-operation Table (MOT), that indicates for each instruction, symbolic
mnemonic, length (two, four, or six bytes), binary machine opcode and format of instruction.
4. A table, the Pseudo-Operation Table (POT), that indicates the symbolic mnemonic and
action to be taken for each pseudo-op in pass 2.

5. A table, the Symbol Table (ST), prepared by pass1, containing each label and corresponding
value.

6. A Table, the base table (BT), that indicates which registers are currently specified as base
registers by USING pseudo-ops and what the specified contents of these registers are.

7. A work space INST that is used to hold each instruction as its various parts are being
assembled together.

8. A work space, PRINT LINE, used to produce a printed listing.

9. A work space, PUNCH CARD, used prior to actual outputting for converting the assembled
instructions into the format needed by the loader.

10. An output deck of assembled instructions in the format needed by the loader.

21. What is symbol table, literal table, pool table?

Ans Symbol Table : A symbol table is a data structure used by a language translator such as a
compiler or interpreter, where each identifier (or symbol) in a program's source code is
associated with information relating to its declaration or appearance in the source.
Literal Table : Literal table is used for keeping track of literals that are encountered in
the programs. • We directly specify the value, literal is used to give a location for the value. •
Literals are always encountered in the operand field of an instruction.
Pool Table : Awareness of different literal pools is maintained using the auxiliary table
POOLTAB.
22. Explain absolute loader scheme with its advantages and disadvantages.
Ans: The advantage of absolute loader is simple and efficient. But the disadvantages
are, the need for programmer to specify the actual address, and, difficult to use
subroutine libraries.
23.What is compiler?
Ans : A compiler is a program that translates a high-level language (for example, C,
C++, and Java) into a low-level language (object program or machine program).
24.Explain different phases of compiler?

Ans : The compilation process contains the sequence of various phases. Each phase takes
source program in one representation and produces output in another representation. Each
phase takes input from its previous stage.

There are the various phases of compiler:

 Fig: phases of compiler

Lexical Analysis:

Lexical analyzer phase is the first phase of compilation process. It takes source code as input.
It reads the source program one character at a time and converts it into meaningful lexemes.
Lexical analyzer represents these lexemes in the form of tokens.

Syntax Analysis

Syntax analysis is the second phase of compilation process. It takes tokens as input and
generates a parse tree as output. In syntax analysis phase, the parser checks that the expression
made by the tokens is syntactically correct or not.

Semantic Analysis

Semantic analysis is the third phase of compilation process. It checks whether the parse tree
follows the rules of language. Semantic analyzer keeps track of identifiers, their types and
expressions. The output of semantic analysis phase is the annotated tree syntax.
Intermediate Code Generation

In the intermediate code generation, compiler generates the source code into the intermediate
code. Intermediate code is generated between the high-level language and the machine
language. The intermediate code should be generated in such a way that you can easily
translate it into the target machine code.

Code Optimization

Code optimization is an optional phase. It is used to improve the intermediate code so that the
output of the program could run faster and take less space. It removes the unnecessary lines of
the code and arranges the sequence of statements in order to speed up the program execution.

Code Generation

Code generation is the final stage of the compilation process. It takes the optimized
intermediate code as input and maps it to the target machine language. Code generator
translates the intermediate code into the machine code of the specified computer.

25.What is conditional macro?

Ans : Conditional assembly are frequently considered to be mechanisms that allow a single version of
the source code for a program to be used to generate multiple versions of the executable. ... It is
also referred to as conditional macro expansion. Conditional Assembly can be achieved with the
help of AIF and AGO statements.

26 How to define micro?

Ans Macro is a unit of specification of program generation through expansion. It is single line
abbreviation for group of instructions Typically MACRO is defined at start of program or at
end of program.

Macro Definition Syntax :-

1) Macro header :- It contains keyword ‘MACRO’.

2) Macro prototype statement syntax :-

< Macro Name > [ & < Formal Parameters > ]

3) Model Statements :- It contains 1 or more simple assembly statements, which will replace
MACRO CALL while macro expansion.

4) MACRO END MARKER :- It contains keyword ‘MEND’.

Example of MACRO :-

Start of definition - MACRO

Macro name ( Prototype ) – My MACRO

Macro body (Model Statements ) – ADD AREG, X

ADD BREG, X

End of Macro Definition - MEND

 27.How to call macro?
Ans < MACRO NAME > [<ACTUAL Parameters > ]

28. Explain how to design of two pass macro processor?

Ans : https://www.wikinote.org/mod/page/view.php?id=350
29. What is input for pass1 and pass2 of two pass macro processor?

30.What is dynamic linking?

Ans: Dynamic linking consists of compiling and linking code into a form that
is loadable by programs at run time as well as link time. The ability to load
them at run time is what distinguishes them from ordinary object files.
31. Explain following
a. Compile and Go,
b. General Loader Scheme,

c. Absolute Loaders,
d. Relocating Loaders,
e. Direct linking Loaders,
32. Difference between absolute loader and relocating loader?
ans: The biggest difference between these two loaders is that absolute loaders will load files
into a specific location and a relocating loader will place the data anywhere in the memory.

33.Differnce between static and dynamic linking?

Ans: The main difference between static and dynamic linking is that static linking copies all library
modules used in the program into the final executable file at the final step of the compilation while in
dynamic linking, the linking occurs at run time when both executable files and libraries are placed in
the memory

34. What is OS?

Ans: An operating system is a program that acts as an intermediary between the user and the
computer hardware. The purpose of an OS is to provide a convenient environment in which
user can execute programs in a convenient and efficient manner. It is a resource allocator
responsible for allocating system resources and a control program which controls the
operation of the computer h/w.

35. What is function of OS?

Ans: An operating system has three main functions:
i. manage the computer's resources, such as the central processing unit, memory, disk
drives, and printers,
ii. establish a user interface, and
iii. execute and provide services for applications software.

36. Explain process state model?

Ans: There are various types of process state model. Process state defines current state of a process.
The process states are new, ready, running, waiting, suspended waiting, terminated etc.
New state: The process is being created.
Ready state: The process is ready to run, but waiting to be assigned a processor.
Running state: Program is running in other words instructions are being executed.
Waiting state: Process preempted and switched from running state to waiting state because of
process is waiting for some event to occur such as I/O completion.
Terminated state: This state is final state, when process is completed or finished execution it moves
from running state to terminated state.

37.What is Process control block,?

Ans: Process Control Block is a data structure that contains information of the process related
to it. The process control block is also known as a task control block, entry of the process
table, etc.
It is very important for process management as the data structuring for processes is done in
terms of the PCB. It also defines the current state of the operating system.

38.What is thread?
Ans: A thread is a path of execution within a process. A process can contain multiple
threads.

39.Difference between process and thread?

Ans: The primary difference is that threads within the same process run in a shared memory
space, while processes run in separate memory spaces.
Threads are not independent of one another like processes are, and as a result threads share
with other threads their code section, data section, and OS resources (like open files and
signals). But, like process, a thread has its own program counter (PC), register set, and stack
space.

40.Explain thread life cycle?

Ans: A thread goes through various stages in its lifecycle. For example, a thread is born, started, runs,
and then dies. The following diagram shows the complete life cycle of a thread.

1. NEW – a newly created thread that has not yet started the execution
2. RUNNABLE – either running or ready for execution but it's waiting for resource
allocation
3. BLOCKED – waiting to acquire a monitor lock to enter or re-enter a synchronized
block/method
4. WAITING – waiting for some other thread to perform a particular action without any
time limit
5. TIMED_WAITING – waiting for some other thread to perform a specific action for a
specified period
6. TERMINATED – has completed its execution

41.What is multithreading?
Multithreading in Java is a process of executing multiple threads simultaneously.
however, we use multithreading than multiprocessing because threads use a shared memory
area. They don't allocate separate memory area so saves memory, and context-switching
between the threads takes less time than process.
Java Multithreading is mostly used in games, animation, etc

42.What is preemptive scheduling?

Ans: In this, a scheduler may preempt a low priority running process anytime when a high priority
process enters into a ready state. When scheduling takes from either of below circumstances it
is preemptive scheduling –
 When a process switches from the running state to the ready state (for example, when an
interrupt occurs).
 When a process switches from the waiting state to the ready state (for example, at
completion of I/)).

43. What is nonpreemptive scheduling?

Ans: In this, once a process enters the running state it cannot be preempted until it completes
it’s allocation time. When scheduling takes place only under below circumstances we say
that the scheduling scheme is non-preemptive or cooperative. –
 When a process switches from the running state to the waiting state (for example, as the
result of an I/O request or an invocation of wait() for the termination of a child process).
 When a process terminates.

44. Explain in short following Scheduling Algorithms:

1. FCFS:
The FCFS is implemented with the help of a FIFO queue. The processes are put into
the ready queue in the order of their arrival time. The process that arrives first
becomes the head of the queue while the others that arrive after are added to the rear
of the queue. In First Come First Served (FCFS) algorithm, the process that arrives
first, is sent first for execution by the CPU when CPU is free
2. SJF:
In this algorithm, the process with the least burst time is processed first. The burst
time of only those processes is compared that are present or have arrived until that
time. It is also non-preemptive in nature. Its preemptive version is called Shortest
Remaining Time First (SRTF) algorithm.
3. RR:
Round Robin(RR) scheduling algorithm is mainly designed for time-sharing systems.
This algorithm is similar to FCFS scheduling, but in Round Robin(RR) scheduling,
preemption is added which enables the system to switch between processes.
4. Priority:
In this scheduling, processes are scheduled according to their priorities, i.e., highest
priority process is scheduled first. If priorities of two processes match, then
schedule according to arrival time. Here starvation of process is possible.

45. what is Semaphore, Mutex?

Ans: It is a synchronization tool used to solve complex critical section
problems. A semaphore is an integer variable that, apart from initialization, is accessed only
through two standard atomic operations: Wait and Signal.

46. Explain
1. Reader writer problem,
 2. Producer Consumer problem,
3. Dining Philosopher problem.
47. What is deadlock ?
Ans: Deadlock is a situation where a set of processes are blocked because each process is
holding a resource and waiting for another resource acquired by some other process.

48. Explain the

1. Deadlock prevention,
2. Deadlock avoidance
3. Deadlock detection,
4. Deadlock recovery.
Ans: 1) Deadlock prevention: The idea is to not let the system into a deadlock
state. Prevention is done by negating one of above mentioned necessary conditions for
deadlock.
2) Deadlock avoidance is kind of futuristic in nature. By using strategy of “Avoidance”, we
have to make an assumption. We need to ensure that all information about resources which
process will need are known to us prior to execution of the process. We use Banker’s
algorithm (Which is in-turn a gift from Dijkstra) in order to avoid deadlock.
3) Deadlock detection and recovery: Let deadlock occur, then do pre emption to handle it
once occurred. Ignore the problem altogether: If deadlock is very rare, then let it happen and
reboot the system. This is the approach that both Windows and UNIX take.

49. Explain the memory management?

50. What is Fixed Partitioning, Dynamic Partitioning?
Ans: Fixed Partitioning:
This is the oldest and simplest technique used to put more than one process in the main
memory. In this partitioning, the number of partitions (non-overlapping) in RAM is fixed
but the size of each partition may or may not be the same. As it is a contiguous allocation,
hence no spanning is allowed. Here partitions are made before execution or during system
configure.
Variable Partitioning :
It is a part of Contiguous allocation technique. It is used to alleviate the problem faced by
Fixed Partitioning. In contrast with fixed partitioning, partitions are not made before the
execution or during system configure.

51.Explain First Fit, Best Fit, Next Fit methods?

 First Fit: In the first fit, the partition is allocated which is first sufficient from the top of
Main Memory.
 Best Fit: Best fit allocates the process to a partition which is the smallest sufficient
partition among the free available partitions.
 Next fit: Next fit is a modified version of ‘first fit’. It begins as the first fit to find a free
partition but when called next time it starts searching from where it left off, not from the
beginning. This policy makes use of a roving pointer
Next fit is a very fast searching algorithm and is also comparatively faster than First Fit and
Best Fit Memory Management Algorithms.

52.What is paging ?
 Ans : In Operating Systems, Paging is a storage mechanism used to retrieve processes from
the secondary storage into the main memory in the form of pages.

53.what is segmnetation?
Ans: :In Operating Systems, Segmentation is a memory management technique in which the memory is
divided into the variable size parts.

54.what is page table

Ans : A page table is the data structure used by a virtual memory system in a computer
operating system to store the mapping between virtual addresses and physical addresses. ...
The page table is a key component of virtual address translation that is necessary to access
data in memory.

55.what is page size

Ans: With computers, page size refers to the size of a page, which is a block of stored memory. Page
size affects the amount of memory needed and space used when running programs. Most operating
systems determine the page size when a program begins running. ... A page size includes all of the files
that create the web page.

56.what is frame?
Ans : It is the smallest unit of data for memory management in a virtual memory operating system. A
frame refers to a storage frame or central storage frame. In terms of physical memory, it is a fixed sized
block in physical memory space, or a block of central storage.

57. what are page replacement policy

Ans : Page replacement algorithms are an important part of virtual memory management and it
helps the OS to decide which memory page can be moved out, making space for the currently
needed page. However, the ultimate objective of all page replacement algorithms is to reduce
the number of page faults.

58. what are advantages of First In First Out (FIFO), Last Recently Used(LRU),
Optimal page replacement(OPR).
Ans : FIFO : Advantages of FIFO The FIFO method has four major advantages: (1) it is
easy to apply, (2) the assumed flow of costs corresponds with the normal physical flow of
goods, (3) no manipulation of income is possible, and (4) the balance sheet amount for
inventory is likely to approximate the current market
LRU :
1. LRU : It is open for full analysis.
2. In this, we replace the page which is least recently used, thus free from Belady’s
Anomaly.
3. Easy to choose page which has faulted and hasn’t been used for a long time.
OPR:
1. Complexity is less and easy to implement.
2. Assistance needed is low i.e Data Structure used are easy and light.

59. What is Thrashing?

Ans : thrashing occurs when a computer's virtual memory resources are overused, leading to a constant
state of paging and page faults, inhibiting most application-level processing.[1] This causes
the performance of the computer to degrade or collapse. The situation can continue indefinitely until
either the user closes some running applications or the active processes free up additional virtual
memory resources.

60. What is translation Look aside Buffer?

Ans : A translation lookaside buffer (TLB) is a memory cache that is used to reduce the time
taken to access a user memory location. ... The TLB stores the recent translations of virtual
memory to physical memory and can be called an address-translation cache.