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Question: Discuss About The Applications As Well As Operating Systems? Answer: Introducation Abstract: In a present era of computing, applications as well as operating systems, efficient memory not able to survive without management, especially if an application for an undefined long time should be subject to serious load. To increase the performance resources should be used efficiently. Real time systems have to use memory to perform efficiently from time to time, otherwise, the purpose of real time system will be lost. It is completely a responsibility of OS to give assistance for the memory management processes through various methods as it acts as the key resource such as the interface that runs on hardware plus applications. Diverse memory allocation algorithms have been designed to organize memory according to the needs and scenarios of use in different timestamps, but there are issues and challenges to provide full support for the reality of these allocations. In any operating system, our management is controlled by various aspects like memory management, hardware lev el, application level and operating system level memory management in particular. Introduction: Operating system acts as the interface between the hardware and the end user. It controls the operation and processing of the computer system. And it is also defined as a program that manages the computer hardware. The mainframe operating system is designed mainly to optimize the use of hardware. The personal computer OSs support multifaceted games, diverse business applications as well as for all in between, the operating system for mobile or versatile computers give an atmosphere in which the user can effortlessly interface to execute the program with a computer. In this way, some OS are planned to be well-situated, for others to become efficient, and by a few combination of the other two. Literature Review: Dynamic memory management plays an important role in memory management because the overhead associated with static memory management is allocated for the program that runs on time compilation and does not use any block of memory Which cannot be used by other applications, efficient use of assets and more vibrant memory allocations always heap memory record structure is used, the stack using static memory allocation use DMA makes more efficient than static memory allocation(Vishwasrao Nilesh, 2016). A new diversity of the famous buddy system has been named as a tertiary buddy, which is a better division and reaction time than the differences in other friend systems, with the extension of binary buddy system over time. Tertiary buddy's observation will be presented in the forthcoming sections (Yadav Divakar). Many research has been done to improve the dynamic memory recurrences and the basics of different and sequential fit are always in the improvement area, which has to be improved. Two-level different fit algorithms are one of the improvements of the different fit algorithm. Considering the requirements of real-time systems, different algorithms have been proposed separately from two levels(I.Ripoll). Even some improvements have been done on different algorithms at two levels so that it can be made more suitable for the real-time system. Searching Strategy: Initially, I discovered memory management techniques and methods in the OS are simply increases my understanding about memory management and not to miss the necessary concepts and ideas. In order to obtain relevant research papers with a detailed analysis of emerging memory management techniques, every possible search was conducted in IEEE, digital library, Google Scholar and research paper such as research paper such as research gate were made available in the third part. To get relevant research knowledge I used several keywords like memory management, operating system memory allocation, real time OS memory allocation, issues in memory allocation and techniques for dynamic memory allocation. By researching on various research publishing platforms, I found detailed information about operating system techniques for memory management, allocation, algorithms, and issues associated to these techniques. Selection: After basic studies of operating system memory management, problems related to operating system management as well as traditional techniques of memory management and these appropriate techniques are never utilized for the real-time memory practice, which is less for applications and operating systems (Heikkil). Study Methodology: Rather than a pure proportional analysis of the OS memory management strategies, the main center of attention was on indulgence of OS, memory management methods or techniques and understanding those situations, where these method or techniques are applied. Therefore to focus more on the outcome, an overview as well as essential details of a few new plus pre-existing techniques or methods has been presented appropriately in this study and the important issues associated to these entire algorithms end to the complications associated with these methods or techniques as well as requirements. To answer real-time unique applications research questions. Every technology related to vibrant memory management also has professionals and cons as well as can be superlatively used in a special situation. Mainly algorithms are better versions of formerly discussed schemes like the sequential and separate fit as well as TLSF. The analysis demonstrates that the mention of TLSF is suitable for the real time system in the technique because the internal fragmentation is very low due to TLSF, its reaction time is extremely good, and it is a basic demand of all real time frameworks, where time. The most significant factor is. Apart from this, TLSF allocation in addition to allocation time is a small steady time which makes it faster than all other conventional techniques. Best fit Memory Allocation Algorithm With best fit allocation algorithm the size of the memory block needed by the job is calculated by the below formula After getting the size of block the memory block list is scanned for the smallest block which has with Thus for our problem the allocation of jobs to the memory blocks will be as shown bellow Job Number Requested Memory Allocated Memory Block Memory Block Size Job A 57K Block 4 300K (high-order memory) Job C 50K Block 3 200K Job D 701K Block 1 900K (low-order memory) Job B which requires 920K will not be allocated to the remaining Block 2 which is of size 910K since the memory block size is not enough to satisfy its requirement, it requires at least 920 memory block size. First Fit Memory Allocation Algorithm In this approach jobs are allocated to the free memory blocks, by searching through the free memory blocks and once an enough memory block is found it is allocated, without considering the memory blocks which havent been reached. It finishes after finding the first suitable free partition. Job Number Requested Memory AllocatedMemory Block Memory Block Size Job A 57K Block 1 900K (low-order memory) Job C 50K Block 2 910K The bellow jobs were not allocated to any free memory block since, after allocating Job A to Block 1; the remaining blocks were not enough for B and after allocating Job 2 to Block 3, and none of the remaining blocks was enough for job D. Thus the below jobs were not allocated. Job D 701K Job B 920K Fragmentation occurs within a very vibrant memory allocation framework when several free blocks are seriously very small to convince any request. External Fragmentation: It occurs when the dynamic algorithm of memory allocation allocates a few memory as well as a very small piece remains that cannot be successfully utilized. If a large amount of external fragmentation happens than the usable memory reduced drastically. Overall memory space presents just to convince a request, however it is never be contiguous. When a process loads and is removed from memory, the blank space creates a hole in the memory space, and there are several holes in a memory space and this is named as external fragmentation. Even though the very first fit as well as the perfect fit can change the actual external fragmentation amount, it cannot be completely eliminated. Compaction can be the perfect solution for outer fragmentation. Internal Fragmentation: This is a space which is wasted within allocated memory systems or blocks due to constraints on the permissible sizes of all allocated blocks. All owed or allocated memory might be to some extent larger than the requested memory therefore this difference in sizes cause partition of memory, however not being utilized. Internal Fragmentation simply a area or a region as well as a page which never utilized by the work occupying that particular region or for a page. Also this space is completely unavailable for employ by the framework until that specific job is not finished completely and the region or page is released. When the process is slightly more than the requested memory from the memory process, it creates an empty space in an allotted block, which creates internal fragmentation. The fundamental reason behind incidents of internal as well as external or outer fragmentation is that inner or internal fragmentation happens when the memory is split into blocks of fixed size while the external fragmentation happens when the memory variable is divided into the size blocks. When the allocated memory block in the process becomes to some extent larger than the requested memory, after that space left in an allocated memory model or block is due to internal fragmentation. On the other hand, when the procedure is detached from memory, then it creates complimentary space, which causes a hole within a memory and it is named as external fragmentation. Number of pages needed to store the entire job To store page number: 3 bits To store offset:7 bits By using FIFO algorithm, By using FIFO Yes, by increasing the size of memory, the number of page fault would decrease. In FCFS jobs are executed in the order of their arrival, therefore order of processing is, Since, arrival time is 0, The whole time needed to practice five jobs is, (CPU time of A) +(CPU time of B)+ (CPU time of C)+(CPU time of D ) +(CPU time of E) In SJN or SJF, a job with shortest execution time is selected for execution. In above problem the jobs are processed in order, The whole time needed to practice five jobs is, (CPU time of B) +(CPU time of E)+ (CPU time of D) + (CPU time of A ) + (CPU time of C) B,C,D,E will be in queue by the time the first job A is finished their arrival time is less than the CPU cycle of A. It is executed based on the First Come First Serve basis on arrival time. Shortest CPU cycle is for job E having 1 CPU cycle, so it will execute first. Based on the ascending order of CPU cycle B,D, C, A will be in queue. Shortest Remaining Time will select the job for execution which has the least amount of remaining time until its completion. Job E has the shortest remaining time and so it will be executed first. When it is finished, then jobs in queue will be in order as B, D, C, A, C, D, A, AIn Round Robin the time slices gets assigned to each of the jobs in equal portions and in a circular order which handles all processes irrespective of their priority.Since we are using a quantum time of 5 but ignoring the context switching and natural wait time required, sojob A is executed first. After it gets finished then next jobs will be in order as B, C, D, E, A, C, D, A. References: NileshVishwasrao and PrabhudevIrabashetti (2016), Dynamic Memory Allocation: Role in Memory Management, International Journal of Current Engineering and Technology, Vol. 4, No. 2, April 2014. Masmano, I.Ripoll, A. Crespo, and J. Real (2004) TLSF: a new dynamic memory allocator for real-time systems, Real-Time Systems, 2004. ECRTS 2004. Proceedings. 16th Euromicro Conference. Mohamed A. Shalan (2003) Dynamic Memory Management for Embedded Real-Time Multiprocessor System On a Chip, A Thesis in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy from School of Electrical and Computer Engineering ,Georgia Institute of Technology, November 2003. Seyeon Kim (2014).Node-oriented dynamic memory management for real-time systems on ccNUMA architecture systems, University of York Department of Computer Science, conference paper April 2014. ValtteriHeikkil (2017)A Study on Dynamic Memory Allocation Mechanisms for Small Block Sizes in Real-Time Embedded Systems, University of Oulu Department of Information Processing Science.