Hello, can you please look at the questions and responses and clean it up a bit. Just make it sound better overall. Add information if it is lacking and just make it sound good as a response. Primarily with 6 delete info if you can. Correct info if it is wrong. Thank you

1) Trace the history of the operating system, beginning with the origin of computers, and ending with the modern era. Be sure to cover all major advances, and to pinpoint where in the timeline what we could consider an operating system first came into use.

Computer's concept was given by charles babbage in 19th century.

When there was no operaing system , then you had to change the connections of the wire to change the functioning of the computer.

then after sometimes punch cards or magnetic tape was used to give the instructions to the computer.You had to clear out the first program from the memory, then you had to load that program you want to run.

If you want to run multiple programs at the same time then you have to use an operating system. So thats how the need of using an operating system felt.

On August 28, 1980 , MS -DOS invented by microsoft was the first operating system for PCs. Instead of typing commands you can use the mouse for the selection.

For the 16 bit PDP -11 machines, the digital equipment corporation created several OS. In mid 1970 small computers came , 8 bit processor , with rudimentary I/P and O/P. On november 20,1985 ,Window 1.0 came , it has 16 bit multitasking shell running over existing MS-DOS.

On 15 decembr , 1999 Windows 2000 released , it was used for both client and sever computers. Windows XP released on 24 august , 2001. windows vista used for pc released on 8 novembr 2006. Windows 7 of microsoft released on 22 july 2009. On 1 august 2012 , as a part of windows NT family of OS , Windows 8 was released.

Windows phone 8 is 2nd gen. of windows phone mobile OS , released on 29, october 2012, speciality was a flat user interface.windows 10 was released in september 2014. Google's android is a mobile Os , developed by Google. It is basically designed for the touchscreen mobiles.

Android was unveiled in 2007 , then apple's MAC OS X came into existence for only the apple users.

6) Write pseudo code for Fifo and Shortest Job First scheduling. Then explain the difference between the two, and explain when the use of each would be the ideal choice.

FIFO

In working frameworks that utilization paging for memory administration, page substitution calculation are expected to choose which page should have been supplanted when new page comes in. At whatever point another page is alluded and not present in memory, page blame happens and Operating System replaces one of the current pages with recently required page. Diverse page substitution calculations recommend distinctive approaches to choose which page to supplant. The objective for all calculations is to decrease number of page flaws.

Initially In First Out (FIFO) page substitution calculation

This is the least complex page substitution calculation. In this calculation, working framework monitors all pages in the memory in a line, most established page is in the front of the line. At the point when a page should be supplanted page in the front of the line is chosen for expulsion.

Illustration - 1. Consider page reference string 1, 3, 0, 3, 5, 6 and 3 page spaces.

At first all spaces are unfilled, so when 1, 3, 0 came they are apportioned to the void openings > 3 Page Faults.

at the point when 3 comes, it is as of now in memory so > 0 Page Faults.

At that point 5 comes, it isn't accessible in memory so it replaces the most seasoned page opening i.e 1. >1 Page Fault.

At long last 6 comes, it is additionally not accessible in memory so it replaces the most established page space i.e 3 >1 Page Fault.

So add up to page shortcomings = 6.

Case - 2. Consider the accompanying reference string: 0, 2, 1, 6, 4, 0, 1, 0, 3, 1, 2, 1.

Utilizing FIFO page substitution calculation

In this way, add up to number of page issues = 9.

Given memory limit (as number of pages it can hold) and a string speaking to pages to be alluded, compose a capacity to discover number of page shortcomings.

Prescribed: Please attempt your approach on {IDE} to start with, before proceeding onward to the arrangement.

Execution Let limit be the quantity of pages that memory can hold. Give set a chance to be the present arrangement of pages in memory.

1-Start navigating the pages.

I) If set holds less pages than limit.

an) Insert page into the set one by one until

the extent of set achieves limit or all

page demands are prepared.

b) Simultaneously keep up the pages in the

line to perform FIFO.

c) Increment page blame

ii) Else

In the event that present page is available in set, do nothing.

Else

a) Remove the principal page from the line

as it was the first to be entered in

the memory

b) Replace the primary page in the line with

the present page in the string.

c) Store current page in the line.

d) Increment page deficiencies.

2. Return page shortcomings.

Beladys anomaly

Beladys anomaly proves that it is possible to have more page faults when increasing the number of page frames while using the First in First Out (FIFO) page replacement algorithm. For example, if we consider reference string 3, 2, 1, 0, 3, 2, 4, 3, 2, 1, 0, 4 and 3 slots, we get 9 total page faults, but if we increase slots to 4, we get 10 page faults.

Shortest Job first Scheduling

Shortest job first initially relies upon the normal running time of the procedures. The exact assessments of these measures help in the usage of the most brief activity first in a domain, which generally makes the same about difficult to actualize. This is on account of regularly the execution burst of procedures does not occur previously. It can be utilized as a part of intuitive situations where past examples are accessible to decide the normal time between the holding up time and the summons. Despite the fact that it is disadvantageous to utilize the most brief activity first idea in here and now CPU booking, it is considered exceedingly invaluable in long haul CPU planning. Additionally, the throughput is high on account of most brief employment first.

Most brief occupation first additionally has its offer of disservices. For one, it can cause process starvation for longer employments if there are countless procedures. Another is the need to know the execution time for each procedure already. Regularly, this is relatively unimaginable in numerous situations.

In this calculation, the procedure that has the most brief CPU burst time is chosen first for the execution.

At the point when the CPU is accessible it is allocate to the procedure that has the littlest next CPU burst.

On the off chance that two procedures have a similar length of CPU burst then FCFS strategy is utilized to comprehend the tie.

Truth be told more proper term for this calculation would be the "Following Shortest CPU Burst Time First" since it apportions the CPU by inspecting the length of the following CPU burst of a procedure instead of its aggregate length of a burst time.

SJF calculation might be either preemptive or non-preemptive.

At the point when another procedure arrives having a short CPU burst time than the as of now executing process; preemptive SJF calculation will seize the as of now executing process, and designates the CPU to the recently arrived process where as a non-preemptive SJF calculation will enable the present running procedure to complete its CPU burst.

Preemptive SJF booking is likewise alluded to as Shortest Remaining Time Next (SRTN) planning.

Les us perceive how this approach functions for the booking of procedures with the assistance of an illustration.

Non-Preemptive SJF

Consider the accompanying procedures and their CPU burst time (in millis.) and discover normal holding up time and normal turnaround time utilizing non-preemptive SJF strategy.

Process Burst Time (plants.)

P1 9

P2 4

P3 5

P4 7

P5 3

Add up to 28

According to the lead of Shortest Job First CPU will be dispensed to the procedure with the most brief CPU burst time so in our illustration, process P5 has the most brief CPU burst time so clearly process P5 will get the CPU first for execution in this manner sitting tight time for P1 will be zero.

After that procedure P2 has the littlest CPU burst so P2 will get next tern after fulfillment of P1 so process P2 needs to sit tight for 3 milliseconds which is the finishing time for process P5.

Next turn is for process P3 with most brief burst time 5 milliseconds. sitting tight time for process P3 will be computed as 3 + 4 = 7 (burst time of P5 and P2). It can be spoken to in the gantt diagram as take after:

Most limited Job First

Add up to Waiting Time:

P1 = 19 + P2 = 3 + P3 = 7 (3+4) + P4 = 12 (3+4+5) + P5 = 0 (ms)

= 41 factories.

Avg. Holding up Time :

Avg. Holding up Time = Total Waiting Time/No.of Process

= 41/5

= 8.2 factories.

Add up to Turnaround Time :

P1 = 28 + P2 = 7 + P3 = 12 + P4 = 19 + P5 = 3

= 69 plants.

Avg. Turnaround Time :

Avg. Turnaround Time = Total TurnaroundTime/No.of Process

= 69/5

= 13.8 plants.

2) Explain the difference between a fixed and a dynamic partition. Be sure to create your own diagrams (do not use one from any other source) for each of the two types of partitions.

Fixed Partition

4mb - OS

4mb

4mb

4mb

4mb

4mb

4mb

4mb

Dynamic Partition

4mb - OS

3mb

3mb

6mb

2mb

6mb

1mb

7mb

Difference between the two

Fixed Partition

1) It is assigned to the stack.

2) Its size is known at the compile time.

3) At the compile time it is performed.

4) It follows the first in last out principle.

Dynamin Partition

It is assigned to the heap. Its size might be unknown at the compile time. At the run time it is performed. There is no fixed order of assignment.