Sunday, 10 February 2019

Introduction and System Structure

Q.1: What is the difference between logical address and physical address?


Logical address
Physical address
It is the virtual address generated by CPU
The physical address is a location in a memory unit.
The user can view the logical address of a program.
The user can never view physical address of program
The Logical Address is generated by the CPU
Physical Address is Computed by MMU
The user uses the logical address to access the physical address.
The user can not directly access physical address.
Set of all logical addresses generated by CPU in reference to a program is referred as Logical Address Space.
Set of all physical addresses mapped to the corresponding logical addresses is referred as Physical Address.

Q.2: Mention one characteristic each of time sharing system and batch processing system.
The characteristic of time sharing system is that the CPU is allocated to each user in term for a small  time. as soon as the time slice is over the CPU switches to the next user. This system uses CPU scheduling and multi-programming where is in batch processing system, jobs where submitted in batch to the computer the term that means the job where submitted in basis to the computer in order to identity the various jobs and its functions, special control card, job control language card where use scheduling of job in the system may be FCFS or SJN. Here in this system at most one program is in execution no time division management is required. It has a better scope for resource utilization due to its serial processing.

Q.3: Write short note on
i) time sharing OS or batch processing.
ii) real time system.
iii) Spooling.
iv) dual mode operation.
i) Time sharing OS or batch processing

Time sharing system is also known as multi user systems. The CPU execute multiple job by switching among them but the switches occurs so frequently. That the user can interact with each program while it is running. An interactive computer system provides direct communication between user and system. The user gives instruction to the operating system or to a program to directly using  keyboard or Mouse and weight for immediate result. So the response time will be so what the time sharing system allows many user to share the computer simultaneously since each action in the system is not only a little CPU time is needed for each user.
The disadvantage of time sharing system are:
Time sharing system is more Complex than multi-programming operating system.
The system must have memory management and protection.
Time sharing system must also provide a file system so disk management is required.
It provides mechanism for concurrent execution which required Complex CPU scheduling scheme.

ii) Real time system

Real time system is used when there are rigid time requirement on the operation of a processor. Sensor bring data to computer the computer analyse data and adjust control to modify the sensor inputs. System that control scientific experiment, medical imaging system and some display system a real time system.

The main disadvantage of real  time system:

Real time system is considered to function correctly only. It return to the correct result within the time constant.
Secondary storage is limited or missing instead data is usually stored In short term memory or ROM advanced voice feature are absent.
Real time system is of 2 types such as:
i)hard real time system.
ii)Soft  real time system.
i)hard real time system: It graduate that the critical task has been completed on time the certain task is take place at certain instant of time.
ii)Soft  real time system: restrictive type of real time system where a critical task get priority over the  normal task handwritten the priority unit it computers. these have more Limited Unity than hard real system.

iii) Spooling

Spool stands for simultaneous peripheral operation online. It uses the disc as a hug buffer for reading from input device and for storing output data until the output device accept them. It is also used for processing data at remote  side the remote processing is done and it on speed with no CPU intervention spooling overlap the input output one job with computation of other job Spooling has a beneficial effect on the performance of the system by keeping both CPU and input device working at much higher time.

iv) Dual mode operation

Dual mode of operation is distinction between execution of user mode and kernel or supervisor mode. A mode bit is added to the hardware to indicate the current mode that is kernel (0) or user (1) Dual mode of operation provide us with more protection to the operating system. For example if kernel instruction is executed under user mode the hardware does not execute it although identifies it as an illegal execution and trap it to the operating system.

Operating System word cloud concept
Q.4) Mention one characteristic of distributed system.
  1. Resource sharing
  2. Openess
  3. Concurrency
  4. Scalability
  5. Fault Tolerance
  6. Transparency
Q.5: Differentiate between multiprogramming and multitasking Operating System

Sl.No.  MultiprocessingMultiprogramming
Multiprocessing refers to processing of multiple processes at same time by multiple CPUs.
Multiprogramming keeps several programs in main memory at the same time and execute them concurrently utilizing single CPU.
Multiprocessing utilizes multiple CPUs.
Multiprogramming utilizes single CPU.
Multiprocessing permits parallel processing.
In Multiprogramming Context switching takes place.
In the Multiprocessing Less time taken to process the jobs.
Multiprogramming taken more time to process the jobs.
Multiprocessing is Usually more expensive.
Multiprogramming systems are less expensive.

Q.6: What is bootstrapping? distinguish between multiprogramming and multithreading operating system? state the function of batch processing.
Bootstrapping is the process of loading a set of instruction when a computer is first turned on a rooted. During the start the process Diagnostic test are performed such as power on self test or check configuration for the device and implement routing testing for the connection of peripheral hardware and external device the bootstrap for a program is  then load to initialize the OS.
Batch operating system.
The user of batch operating system do not interact with the computer directly. Each user prepare his job on and off line device like punch card and submit to it two computer operator.
Batch operating system is one where programs and data are collected together in a batch before processing start memory management in batch system is very simple memory is usually divided into two area.
i) Operating system
ii) User area
scheduling is also simple in batch system job are processed in the order of submission date is First Come First served.
Advantage of batch system
Moved of works of operator to the computer.
increase performance since it was possible for job to start as soon as the previous job finished
Job could enter an infinite loop
difficult to debug program.

Q.7 What is the difference between time sharing and batch system?
Ans: Coming soon.

Q.8: What is a multi user, multiprogramming operating system?
Multiprogramming operating system: When two or more programs are in a memory at a time sharing the processor is referred to the multiprogramming operating system. Multiprogramming and humour single processor that is being shared it increase CPU utilizatied by organising job so that the CPU always has is one execute. The operating system keeps several jobs in memory at a time this set of job is subject of job kept in job pool.
Multi user operating system: It support simultaneous interaction with multiple user it also support user authentication resource uses accounting for the interactive user and protection for user environments.

Q.9: What is dynamic loading? what is dynamic linking? how they are related?
Dynamic loading: dynamic loading means loading the library into the memory during load or runtime it can be imagined to be similar to plugins that is exec, can actually execute before the dynamic loading happens it retrieves the address of function and variables contained in the library, Execute those functions or excess dose variable and uploaded the library from memory.
Dynamic linking: dynamic linking refers to the linking that is done during load or runtime and not when the exe C is created. in such case of Dynamic linking the link while creating those exec, does minimal work.
Dynamic loading can be done at any point in program execution but linking is performed at the time of program loading only.

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Basic Electronics Engineering (EC101)

Basic Electronics Engineering (EC101)