Computer Technology And Its Impact On Society Essay

Computer Technology And Its Impact On Society Essay
Computer technology has evolved dramatically over the years and has significantly changed society. As technology advances, it transforms and
improves society. Computer–related technology allows for enhancement of social functions previously difficult or impossible to execute. Computers
have also accelerated productivity. Much less time is required nowadays to research information. Many in search of jobs and careers have reaped the
rewards of computer technology. For too long, finding information about various careers was very difficult and painstaking, but the computer has
revolutionized the job–search process. People now have access to virtually endless information on the career of their choice. This has permitted freer
access to career opportunities that is appropriate for their lifestyle. People now can locate thousands of jobs opportunities from their personal
computers. One other component of careers that has been influenced by computers is the development.
Today's generation could never ever imagine in their wildest dreams about the world, ages before, when there were no computers or any other
technologies. So much we have advanced that now every information is just a click away and is in your hands 24/7. All this advancement was
possible only with the introduction of a small device called the "Computer". The computer is considered the most revolutionary invention of the
twentieth century and it appears to be as well. The impact of computer usage can be found in
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Mac Os X
Apple's Macintosh OSX Panther
CS555 Section 3
Tomomi Kotera
Table of Contents
Table of Contents ................................................................ Page 1
Introduction ....................................................................... Page 2
Overview ...........................................................................Page 2
CPU Scheduling ...................................................................Page 3
Symmetric Multiprocessing (SMP) ............................................Page 5
Memory Protection ................................................................Page 6
Virtual Memory ....................................................................Page 7
Technical and Commercial Success of Mac OS X ..........................Page 11
Conclusion ...........................................................................Page 13
Bibliography....................................................................... Page 14

Introduction
The Mac OS X Panther operation system has met with both ... Show more content on Helpwriting.net ...
Mach maintains the register state of its threads and schedules them preemptively in relation to one another. In general, multitasking may be either
cooperative or preemptive. Classic Mac OS implements cooperative multitasking which was not very intelligent. In cooperative CPU scheduling the OS
requires that each task voluntarily give up control so that other tasks can execute, so unimportant but CPU–intensive background events might take up
so much for a processor's time that more important activities in the foreground would become sluggish and unresponsive. On the other hand,
preemptive multitasking allows an external authority to delegate execution time to the available tasks. Mac OS X's Mach supports preemptive
multitasking in which it processes several different tasks simultaneously.
To affect the structure of the address space, or to reference any resource other than the address space, the thread must execute a special trap instruction
which causes the kernel to perform operations on behalf of the thread, or to send a message to some agent on behalf of the thread. In general, these
traps manipulate resources associated with the task containing the thread.
Mach provides a flexible framework for thread scheduling policies. Mac OS X supports both the multilevel feedback queue scheduling and
round–robin (RR) scheduling algorithm. The multilevel feedback queue scheduling

Recovery System Dbms
17. Recovery System in DBMS – Presentation Transcript 1. Chapter 17: Recovery System * Failure Classification * Storage Structure * Recovery and
Atomicity * Log–Based Recovery * Shadow Paging * Recovery With Concurrent Transactions * Buffer Management * Failure with Loss of
Nonvolatile Storage * Advanced Recovery Techniques * ARIES Recovery Algorithm * RemoteBackup Systems 2. Failure Classification * Transaction
failure : * Logical errors : transaction cannot complete due to some internal error condition * System errors : the database system must terminate an
active transaction due to an error condition (e.g., deadlock) * ... Show more content on Helpwriting.net ...
* Buffer blocks are the blocks residing temporarily in main memory. * Block movements between disk and main memory are initiated through the
following two operations: * input ( B ) transfers the physical block B to main memory. * output ( B ) transfers the buffer block B to the disk, and
replaces the appropriate physical block there. * Each transaction T i has its private work–area in which local copies of all data items accessed and
updated by it are kept. * T i 's local copy of a data item X is called x i . * We assume, for simplicity, that each data item fits in, and is stored inside, a
single block. 8. Data Access (Cont.) * Transaction transfers data items between system buffer blocks and its private work–area using the following
operations : * read ( X ) assigns the value of data item X to the local variable x i . * write ( X ) assigns the value of local variable x i to data item { X }
in the buffer block. * both these commands may necessitate the issue of an input (B X ) instruction before the assignment, if the block B X in
which X resides is not already in memory. * Transactions * Perform read ( X ) while accessing X for the first time; * All subsequent accesses are to the
local copy. * After last access, transaction executes write ( X ). * output ( B X ) need not immediately follow write ( X ).

Nt1310 Virtual Memory
Virtual memory is a typical piece of most working frameworks on desktop PCs. It has turned out to be so basic on the grounds that it gives a
major advantage to clients effortlessly. In this article, you will learn precisely what virtual memory is, the thing that your PC utilizes it for and
how to design it all alone machine to accomplish ideal execution. Most PCs today have something like 32 or 64 megabytes of RAM accessible for
the CPU to utilize (perceive How RAM Works for points of interest on RAM). Sadly, that measure of RAM is insufficient to run the majority of the
projects that most clients hope to keep running without a moment's delay. For instance, on the off chance that you stack the working framework, an
email program, a Web program and word processor into RAM at the same time, 32 megabytes is insufficient to hold it all. In the event that there
were no such thing as virtual memory, then once you topped off the accessible RAM your PC would need to say, "Too bad, you can not stack any
more applications. Kindly close another application to load another one." With virtual memory, what the PC can do is take a gander at RAM for
zones that have not been utilized as of late and duplicate them onto the hard plate. This arranges for space in RAM to stack the new application.... Show
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Since hard circle space is such a great amount of less expensive than RAM chips, it additionally has a decent financial advantage.

Uses Of In Operating Systems
Uses of Virtualisation in Operating Systems
Virtualisation in operating systems is a wide ranging subject relating to many topics within operating systems. Waldspurger and Rosenblum define
virtualisation in their article I/O virtualization as "decoupling the logical from the physical, introducing a level of indirection between the abstract and
the concrete." [1] In this essay I will briefly outline some of the many types of Virtualisation as well as talk about benefits and limitations virtualisation
in general.
Due to the term 'virtualisation' referring to so many different areas within operating system, talking about the History of this topic is very hard. In
Modern Operating Systems, Andrew Tanenbaum states "visualization, which is more than 40 years old" [6]. This book was published in 2009,
implying that virtualisation started roughly in the 1969. However, spooling which is an example of I/O virtualisation existed in IBMs SPOOL
system. IBM copyrighted the SPOOL system in 1960 suggesting Virtualisation started on or before the 1960s [7]. From the context of Tanenbaum's
book, it is clear that he is speaking of virtual machine technology which for the confines of this essay will be considered a subset of virtualisation.
Throughout the history of computers more virtualisation techniques have been invented from spooling to virtualised I/O to virtual machines and other
things like RAID. When talking about virtualisation in operating systems, virtual memory is perhaps the

The Development And Development Of The Graphical...
This paper is based on CUDA, a parallel computing platform model, which utilizes the resources of the Graphical Processing Unit (GPU),
increasing the computing performance of our system, hence creating a robust parallel computing unit. In this paper, we will be introducing a brief
history on CUDA, it's execution flow and it's architecture to handle processor intensive tasks. We will also be highlighting some of it's real life
applications and the difference in performance as compared of the only CPU based architectures. Also, since most of the CUDA applications are
written in C/C++, we will also be exploring how CUDA provides the programmable interface in such languages as well. Finally, we will be including
the current research activities... Show more content on Helpwriting.net ...
So, in 2007, NVIDIA released CUDA, which provided the parallel architecture, to support the usage of the GPUs. It was designed to work with
programming languages such as C/C++ or Fortran and this really helped specialists in parallel programming to use CUDA, rather than to learn other
advanced skills in GPU programming[10] . The model for GPU computing is to use a CPU and GPU together in a heterogeneous co–processing
computing model[3]. The framework is designed such that the sequential part of the application runs on the CPU and the computationally–intensive
part is accelerated by the GPU. From the user's point of view, the application is faster because it is using the better performance of the GPU to
improve its own performance. пїј Figure1: Core comparison between CPU and GPU пїј3. Architecture Since GPUs have large number of resources
with hundreds of cores and thousands of threads to be utilized and have very high number of arithmetic and logical units. Hence it provides a huge
parallel architectural framework to work with. пїј Here is a block diagram that generally describes CUDAs architecture. Figure 2: Block diagram for
CUDA Architecture[4] Basic Units of CUDA Figure 2 showed the top level block diagram of the overall architecture of CUDA. Now, exploring more
on to the details, we will be discussing about the basic units of CUDA. пїјпїј Figure 3 : CUDA supported GPU structure [11] The architecture

Nt1310 Unit 1 Memory Questions And Answers
1. Memory unit that interconnects flexibly with the CPU is called the
A) Main memory
B) Secondary memory
C) Supplementary memory
D) Index
Ans:A
2. Data transfer among the main memory and the CPU register proceeds place through two registers namely.......
A) Overall purpose register and MDR
B) accumulator and program security
C) MAR and MDR
D) MAR and Accumulator ans:c 3. An exclusion condition in acomputer system produced by an event outside to the CPU is called........
A) Interrupt
B) Stop
C) Wait
D) Method
Ans: A) Interrupt

4. When the CPU identifies an interrupt, it then protects its .............
A) Earlier State
B) Succeeding State
C) Current State
D) Both A and B
Ans: C) Current State
5. A micro program is... Show more content on Helpwriting.net ...
The channel which switches the multiple requirements and multiplexes the data transmissions from these devices a byte at a time is recognized as.....
A) multiplexor channel
B) the picker channel
C) block multiplex channel
D) None
Ans : A) multiplexor channel
10. The address planning is done, when the program is primarily loaded is called......
A) active relocation
B) rearrangement
C) static relocation
D) dynamic as well as static relocation
Ans : C) static relocation

11. State whether the resulting statement is true or false for PCI bus.
i) The PCI bus tuns at 33 MHZ and can transmission 32–bits of data (four bytes) each clock tick.
ii) The PCI edge chip may support the video adapter, the EIDE disk supervisor chip and may be two external adapter cards.
iii) PCI bus distributes the different throughout only on a 32–bit interface that extra parts of the machine deliver through a 64–bit path.
A) i– True, ii– False, iii–True
B) i– False, ii– True, iii–True
C) i–True, ii–True, iii–False
D) None
Ans : C) i–True, ii–True, iii–False
12. The I/O processor has a straight admission to....................... And covers a number of independent data channels.
A) Main memory
B) secondary memory
C) cache memory
D) None
Ans: A) main

Nt1310 Unit 1 Review Sheet
#include #include "mlist.h" #define HASHSIZE 100000; int size = HASHSIZE; int ml_verbose=0; typedef struct mlnode { struct mlnode
*nextEntry; MEntry *currentEntry; int initiated; } bucket; struct mlist { int size; bucket **hashIndex; }; /** Creating a mailing list with
ml_create(). It uses calloc & malloc for memory allocation, relying on bucket pointers for assignment. (1.) Declaration of pointers and variable 'i' for
loop purpose. (2.) Print statement with "if verbose". Followed by malloc to allocate space for mlist pointer. (3.) Initalize the first bucket pointer and
assigning memory using calloc (allows memory space '0' to be assigned to the very first bucket). (4.) Subsequently, check if any sub buckets exists,
allocate... Show more content on Helpwriting.net ...
It uses two bucket pointes to differentiate exsiting and newly add entries. Return values of each section, 1 being sucessful and 0 being unsuccessul.
(1.) Declaration of variable and pointers (2.) Call for a function look up to see if there is any matching entries. If no, return value '1'.(3.) Set memory
for newly declared pointer, "bucketNew". And if "bucketNew" is empty, set "null" to bucketNew–>nextEntry. (4.) Set a hashindex for each bucket
entry. (5.) Set "buckPresent = buckPresent–>nextEntry" until no more "buckPresent–>nextEntry" exists. (6.) Set next to an empty bucket, and the entry
to mentry **/ int ml_add(MList **ml, MEntry *me) { // No. 1MList *l = *ml; bucket *buckPresent; bucket *bucketNew; unsigned long hashval; int
i; // No. 2 if (ml_lookup(l, me) != NULL) return 1; // No. 3 bucketNew = (bucket *) malloc(sizeof(bucket));

A Novel Memory Forensics Technique For Windows 10
A Novel Memory forensics Technique for Windows 10 Abstract Volatile memory forensics, henceforth referred to as memory forensics, is a subset of
digital forensics, which deals with the preservation of the contents of memory of a computing device and the subsequent examination of that memory.
The memory of a system typically contains useful runtime information. Such memories are volatile, causing the contents of memory to rapidly decay
once no longer supplied with power. Using memory forensic techniques, it is possible to extract an image of the system's memory while it is still
running, creating a copy that can be examined at a later point in time, even after the system has been turned off and the data contained within the
original RAM has dissipated. This paper describe the implementation of the technique that collect volatile artifacts extracted from the RAM dump and
Hibernation file of Windows 10 operating system and shows the extracted data of various process of the system. Keywords: Windows forensics,
Memory forensics, Volatile data, Volatile digital evidence 1.Introduction The use of memory forensic allows the creation of a snapshot of a system at a
particular point in time, known as a memory image. Memory typically contains that information which is never written to disk. Memory forensic
allows the extraction of various types of forensically significant information that would have been disappeared when the system was turned off. Such
information can include running

Operating Systems And Software Systems
An operating system is a system software that manages and control all interaction between a computer hardware and software. There are several types
of operating systems, for example, multi–user, multitasking, single user and more. The first ever created OS date back in the 50's. As computer and
technology progress over time operating system kept evolving. Among the commonly used operating systems of today is Linux, a Unix–like type of
OS. Linux creation begins in 1991 as a software kernel and part of a small project developed by Linus Torvalds, a student from a University in
Finland. Under GNU (general public license), the software was available as a free and open source and gave everyone the right to access, change and
modify its original design. Because of the way it is designed it can run on multiple platforms such has Intel, Alpha and more. Like many open systems,
Compared to more expensive operating systems, Linux was an economical alternative for cost–conscious companies that needed to quickly create
Web–based applications. When more developers are able to provide input about a system, it becomes easier to fix flaws and bugs that hinder
performance; roll out improvements; increase the speed of system evolution; and combine an application 's components in new and exciting ways not
intended by the original developer. (Ecommerce) Linux has three major components the kernel, the system library and the system utility. Some of the
great features of Linux include

Nt1310 Unit 3 Assignment 3 Virtual Memory
COP 4600 – Assignment 4 When we talk about an on–disk backing store, we usually mean the virtual memory allocated to the physical memory. This
virtual memory acts like a 'backup' in case we require a little extra physical memory to handle the execution of the active process(es). This memory
is usually slower than our RAM, however performance can be optimized by ensuring that only those parts or pages of the process that are active are
kept in physical memory. This does agree with the Iron Laws of Memory Hierarchy. RAM is fast and expensive and is used in smaller amounts, while
the on–site backing store is usually larger but slow. Linux uses the virtual memory to free up private or anonymous pages used by a process. When
a page is 'taken off' the physical memory, it is copied to the backing store, also sometimes named swap area. Linux uses the term 'swapping', which
usually refers to swapping a whole process out from another, to describe 'paging', which is the swapping of the inactive pages of a process or
processes. In order to perform the on–disk swap, the page is assigned a swap info struct that describes the area it will possess and the details of the
page. The figure to the right shows what the struct will look like. Some of the more important attributes are flags, swap_file, vfs_mount, swap_map,
lowest_bit,... Show more content on Helpwriting.net ...
The first benefit is that processes now have an increased memory in which to operate. Even a substantially large process can be accommodated by
keeping the process partially active in physical memory and partially inactive on the swap space. The second advantage revolves around the process
initialization. When a process is initialized, there are a bunch of initialization pages referenced early in the process' lifecycle and are never used again.
These pages are inactive and are moved to the on–disk backing store, while the rest of the process' pages do their work using the physical

Components Of Operating Systems Management Functions
Here are the print screens of how I have run this program first input 1 to add data. My input was 25, 80, 10, 5, 40. When I input 20 so there would
be another number waiting to go in the Que. Then I entered 2 to remove data being 25, it removed 25 but did not replace the last number 20 I have
executed the code to run the program. Form what I can see it worked for the first five numbers, but when entering the next number it failed. After
looking at the array within the code, I think it could be where it gets to Array 4 (array are 0 based so there would be five fields). I think that they
could be bracket with square brackets. I am not sure as I have very little knowledge of programing in C Task Two Operating Systems Management
Functions There are four essential operating system management functions that are employed by all operating systems. The four main operating
system management functions (each of which I will be explaining) are: Process management Memory management File and disk management I/O
system management The Low Level Scheduler This deals with the decision as to which job should have access to the processor. The Low level
scheduling will assign a processor to a specific task based on priority level that is ready to be worked on. The Low Level Scheduling will assign a
specific component or internal processor required bandwidth and available bandwidth. The Low level scheduling determines which tasks will be
addressed and in what order. These tasks have

Disk Cache Optimization Using Compressed Caching Technique
Disk Cache Optimization using Compressed Caching Technique Maheshwar Sharma
Gaurav Rawat, Himanshu Banswal, Naman Monga Department of Computer Science, BVCOE, GGSIP University, New Delhi, India
______________________________________________________________________________
Abstract– In this paper we have discussed about the cache and various mapping technique. Then we shift our focus on compressed caching which is
the technique that tries to decrease paging request from secondary storage. We know that there is a big performance gap in accessing the primary
memory (RAM) and secondary storage (Disk). The Compressed caching technique intercepts the pages to be swapped out, compresses them and
stores them in pool allocated in RAM. Hence it tries to fill the performance gap by adding new level to virtual memory hierarchy. This paper analyze
the performance of virtual memory compression. Further to avoid various categories of cache misses we discuss different types of cache technique to
achieve higher performance. Lastly we discuss few open and challenging issues faced in various cache optimization techniques.
Keywords– Cache mapping technique, Cache optimization, Virtual Memory, Zswap, Zbud , LZO, Frontwrap, limit hit
I. INTRODUCTION
Basically, cache is the smallest and fastest memory component in the hierarchy. It is aimed to bridge the gap between the fastest processor to the
slowest memory components at a reasonable

Memory Paging Is A Critical Element Of An Operating System...
Memory paging is a critical element of an operating system's performance and efficiency. Implementing paging allows processes to run even while still
in secondary memory by translating virtual addresses into physical addresses. This research will look at the methods, mechanisms, and algorithms
behind memory paging without regards to a specific operating system. Explanations of the paging process will begin at an elementary, top–level view,
then progress into a detailed view concerning data structures, addressing, page tables, and other related elements. Intel 64 and IA–32 architecture will
be examined and how paging is implemented, specifically through a hierarchical scheme and the use of a translation lookaside buffer. Issues such as
thrashing and speed concerns with regards to the hardware used will also be examined and how algorithms and better hardware can influence these
issues. The research will conclude with how a user can best take advantage of paging to better their memory's performance and speed. Algorithms
concerning how pages are swapped in main memory are related to the paging process and will be mentioned, but are beyond the scope of this paper.
The use of paging, both simple and demand, was a solution to previously used schemes of having either unequal fixed–size or variable sized partitions,
which lead to internal and external fragmentation respectively. The difference between paging and these fixed and dynamic partitioning methods is

Operating Systems May Use The Following Mechanism
Operating systems may use the following mechanisms to avoid attacks of this type: Operating systems can provide sandboxes: Sandboxes are
environments where a program can execute but should not affect the rest of the machine. The trick here is, permitting limited interaction with
outside while still providing the full functionality of the operating system. Or in other words, the file system can be kept out of unauthorized
access and 3rd party softwares may be allowed minimum access to filesystems. Race conditions can also be a critical security issue. To illustrate
such a situation, consider a privileged program that checks if a file is readable and then tries to open it as root. The attacker passes it a symbolic
link, in the interval between the two operations; the attacker removes the link and replaces it with a link to a protected file. This would give him
direct access to the Study of Security in Legendary Sreeyapureddy ABHIYANTRIKI: An International Journal of Engineering & Technology 53
Volume 1, Number 1, November, 2014 (44–57) protected file area and into the system. So here, an attacker takes advantage of the race condition
between two operations to get access into the protected area of the operating system. The only way to overcome such attacks is to provide only atomic
operations to access files and strict restrictions on their access by other users other than root. Security is not only an issue with the operating systems in
desktops and laptops; the

Memory Management and Microprocessor
ABSTRACT
In this paper, we will cover the memory management of Windows NT which will be covered in first section, and microprocessors which will be
covered in second section. When covering the memory management of Windows NT, we will go through physical memory management and virtual
memory management of that operating system. In virtual memory management section, we will learn how Windows NT managing its virtual memory
by using paging and mapped file I/O.
After covering the memory management, we will go through microprocessor. In this section, we will learn a bit about the recent microprocessors, such
as Intel and AMD microprocessors. We also will learn about the trends that affecting the performance of microprocessors.
INTRODUCTION ... Show more content on Helpwriting.net ...
The segmentation scheme in Intel 80386 microprocessor is more advanced than that in Intel 8086 microprocessor. The 8086 segments start at a fixed
location and are always 64K in size, but with 80386, the starting location and the segment size can separately be specified by the user.
The segments may overlap, it allows two segments to share address space. To send the necessary information, segment tables with segment selector as
index are used. At any time, only two segment tables can be active. They are Global Descriptor Table (GDT) and a Local Descriptor Table (LDT).
This two segment table only can be executed by the operating system.
Segment table is an array of segment descriptors which specify the starting address and the size of the segment. Each segment descriptor has 2 bits
specifying its privilege level, called as the Descriptor Privilege Level (DPL). This DPL has to be compared with Requested Privilege Level (RPL) and
Current Privilege Level (CPL) before processor grants the access to a segment. If the DPL of the segment is less than or equals to the RPL as well as
the CPL, then the processor will grant access to a particular segment. This serves as protection mechanism for operating system.
1.2.2.Virtual Memory Management in Windows NT
Windows NT virtual memory manager provides large virtual memory space to applications via two memory management processes. They are called
paging (moving data between

Cache And Various Mapping Technique
Abstract– This paper begins with the discussion about cache and various mapping technique. Then we shift our focus on compressed caching which
is the technique that tries to decrease paging request from secondary storage. We know that there is a big performance gap in accessing the primary
memory (RAM) and secondary storage (Disk). The Compressed caching technique intercepts the pages to be swapped out, compresses them and
stores them in pool allocated in RAM. Hence it tries to fill the performance gap by adding new level to virtual memory hierarchy. This paper analyze
the performance of virtual memory compression. Further to avoid various categories of cache misses we discuss different types of cache technique to
achieve higher performance. Lastly we discuss few open and challenging issues faced in various cache optimization techniques.
Keywords– Cache mapping technique, Cache optimization, Virtual Memory, Zswap, Zbud , LZO, Frontwrap
I. INTRODUCTION
Basically, cache is the smallest and fastest memory component in the hierarchy. It is aimed to bridge the gap between the fastest processor to the
slowest memory components at a reasonable cost. It maintains the locality of information and support the reduction of average access time. The
address mapping converts physical address to the cache address. But when it comes to virtual memory systems, swapping turns out to be the greatest
factor for reduce in performance. Disk latency is around four times to that of accessing the

Final Windows vs. linux Essay examples
UNIX/Linux Versus Mac Versus Windows All right, this is what I have learned about file management in Windows from experience. The first thing
I learned is that in modern windows the OS handles everything it's self to a large degree. You can specify where the files are, as in folders and
differing hard drives, but not the sections of the hard drive they reside on. The next part of file management that can be set by the user with
authorization, mainly the admin, is file clean up. This cover Disk error checking, defragging, backup and disk clean up. Error checking checks the
physical hard drive for the memory and is more along the lines of memory management, but if it isn't done then files will not be... Show more content
on Helpwriting.net ...
I mention this as my one reference, being a web site link had this happen on my current settings when I saved the file. Windows Memory Management
Current Windows operating system memory management (Windows Vista SP1, Server 2008 and later) have implemented memory management
procedures that differ greatly from previously versions of Windows memory management due to previous vulnerabilities with the address space
location of elements such as kernel32.dll, ntdll.dll. Knowing the memory address of such critical files allowed malicious access at the kernel level and
allowed unscrupulous program writes to take advantage of the known locations. Microsoft has implemented new memory access technology that
includes Dynamic Allocation of Kernel Virtual Address Space (including paged and non–paged pools), kernel–mode stack jumping, and Address Space
Layout Randomization. These changes reduce the ability of malicious program developers to take advantage of known address locations. Windows
address space can be larger or smaller than the actual memory installed on the machine. Windows handles memory management with two
responsibilities. The primary is to map or translate the processors virtual address space to the physical memory. The second responsibility is to
manage the swap file between the hard drive and Random Access Memory (RAM). Windows memory management also includes memory mapped
files. Allowing files to be placed into RAM, sequential file

Disadvantages Of Multikernel OS System
Abstract The challenges for OS structures depend on the diversity of hardware like number of cores, memory hierarchy, IO configuration, instruction
sets and interconnects. Multikernel is a new distributed OS system architecture that treats the machine as an independent cores communicate via
message passing. Multikernel OS is better for scalability of hardware to avoid of the problem in traditional operating systems. The result by the end of
paper shows that the performance of multikernel OS is better in scaling and supporting hardware in the future when comparing with traditional OS.
1.Introduction The OS designers have many challenges according to the diversity and changing of hardware. The deployment and optimization for
general purpose... Show more content on Helpwriting.net ...
The multikernel model The multikernel is a distributed OS architecture for heterogeneous multicore machines that communicate with message passing
only. Explicit inter–core communication, hardware–neutral structure and state is replicate not shared, these are the design principles of multikernel.
The advantages of these principles are: improve performance, supporting core heterogeneity, modularity, and reuse the algorithms of distributed
systems. 3.1 Make inter–core communication explicit Using explicit communication will help to use the system interconnect in comparing with
implicit communication where the messages used to update the content of shared memory for cache coherence. The communication explicitly help to
deploy an optimization for the network like pipelines and batching. Enable isolation and resource management on heterogeneous cores and schedule job
on inter–core topology. Allow operations to have split–phase for example; remote cache invalidations. The structure of message passing is modular, so
it easy to update. 3.2 Make OS structure hardware–neural The OS structure is separated from hardware so there are only two aspect of OS: the
messaging transport mechanisms and the hardware

The Core Of Android Architecture
It is the core of Android architecture that forms the foundation of Android. Linux kernel includes hardware drivers, power management, memory
management, process management and binder driver, which provides all the fundamental services needed by the system. Although it is called Linux
kernel, it is not a standard Linux kernel; Google has customized it for Android devices. The main difference between them is the binder driver, which is
an Android–specific inter–process communication mechanism that enables one Android process to call a procedure in another Android process.
Another major difference is the ashmem module, which is an Android version of shared memory allocator, similar to Portable Operating System
Interface (POSIX) shm but with a simpler file–based API. And also the Power Manager has been enhanced to save battery, which is critical for
smartphones.
Libraries
On top of Linux kernel are Libraries, which provide services written in native language like C and C++. It contains a long list of middle wares that
include SQLite, WebKit, SSL, Media, C runtime library. SQLite is responsible for database, WebKit is for browser support, SSL is used to secure
network transmissions.
Android Runtime
This layer contains core libraries and Dalvik Virtual Machine (DVM), which are needed to run Android applications. DVM is the Android
implementation of Java Virtual Machine (JVM), which optimized for mobile apps for less memory consumption and better performance. DVM was

Essay on Cis Memory Management
CIS:328
Abstract
The purpose of this paper is to show how memory is used in executing programs and its critical support for applications. C++ is a general purpose
programming language that runs programs using memory management. Two operating system environments are commonly used in compiling,
building and executing C++ applications. These are the windows and UNIX / Linux (or some UNIX / Linux derivative) operating system. In this
paper we will explore the implementation of memory management, processes and threads.
Memory Management
What is a Memory Model?
A memory model allows a compiler to perform many important optimizations. Even simple compiler optimizations like loop fusion move statements in
the program can influence the ... Show more content on Helpwriting.net ...
Other functions need to be used to segment the virtual memory pages into useful segments. Since virtual memory is allocated by pages, a number of
special paging features can be used on virtual memory that cannot be used on other types of memory. For instance, pages can be locked (to prevent
read/write access), or they can be protected from any particular access mode (read, write, execute).
Heap memory and allocating a memory block
Each program is provided with a default process heap, but a process may optionally allocate any number of additional heaps, if more storage is
needed. The heap functions will manage their virtual memory usage automatically, and therefore heaps can be set to grow if they are being filled up
with data. If a heap is allowed to grow automatically, the heap functions will automatically allocate additional pages as needed. On the x86 architecture
the heap grows in size towards higher memory addresses.
To use heap memory, a heap must first be allocated (or a handle must be obtained to the default heap). Once you have obtained a handle to a heap, you
can pass that handle to the memory allocation functions, to allocate memory from that particular heap.
Managing process specific memory

The cpu executes a large number of programs while its main concern is the excution of uer programs, the cpu is also needed for other system
activities. These activities arecalled processs. A process is a program in execution. Typically a batch job is a process.

How Does Code Access The Same Page Frame Within A Page Table?
OS Assignment –7:Udaydeep Thota Student ID: 010025210
8.5 What is the effect of allowing two entries in a page table to point to the same page frame in memory? Explain how this effect could be used to
decrease the amount of time needed to copy a large amount of memory from one place to another. What effect would updating some byte on the one
page have on the other page?
Ans: If the two entries in a page table point to the same page frame in the memory, then the users can use the same code or sometimes data in the
future. For example if two users wish to use the same code, then instead of loading the code two times in to the table, one user can load it in to one
table initially and later the other user who would like to use that code access the same memory location. This will help both the users to fast access to
memory, less time consumed for context switching and hence overall effectivememory management is done. The main disadvantage in adopting to
this type of technique is that in case of one user updates the data in the table, then the changes would be reflected to other user who uses the same
memory as well. Hence there may be inconsistency between the users who wish to modify and those who would not like to modify it.
8.11 Given six memory partitions of 300 KB, 600 KB, 350 KB, 200 KB, 750 KB, and 125 KB (in order), how would the first–fit, best–fit, and
worst–fit algorithms place processes of size 115 KB, 500 KB, 358 KB, 200 KB, and 375 KB (in order)? Rank the

Windows Nt vs Unix as an Operating System
Windows NT vs Unix As An Operating System
In the late 1960s a combined project between researchers at MIT, Bell Labs and
General Electric led to the design of a third generation of computer operating system known as MULTICS (MULTiplexed Information and Computing
Service). It was envisaged as a computer utility, a machine that would support hundreds of simultaneous timesharing users. They envisaged one huge
machine providing computing power for everyone in Boston. The idea that machines as powerful as their GE–645 would be sold as personal computers
costing only a few thousand dollars only 20 years later would have seemed like science fiction to them.
However MULTICS proved more difficult than imagined to implement and Bell Labs
withdrew ... Show more content on Helpwriting.net ...
Most of these systems were (and still are) neither source nor binary compatible with one another, and most are hardware specific.
With the emergence of RISC technology and the breakup of AT&T, theUNIX systems category began to grow significantly during the 1980s. The term
"open systems" was coined. Customers began demanding better portability and interoperability between the many incompatible UNIX variants. Over
the years, a variety of coalitions (e.g. UNIX International) were formed to try to gain control over and consolidate the UNIX systems category, but
their success was always limited.
Gradually, the industry turned to standards as a way of achieving the portability and interoperability benefits that customers wanted. However, UNIX
standards and standards organisations proliferated (just as vendor coalitions had), resulting in more confusion and aggravation for UNIX customers.
The UNIX systems category is primarily an application–driven systems category, not an operating systems category. Customers choose an application
first–for example, a high–end CAD package–then find out which different systems it runs on, and select one. The final selection involves a variety of
criteria, such as price/performance, service, and support. Customers generally don't choose UNIX itself, or which UNIX variant they want. UNIX just
comes with the package when they buy a system to run their chosen

Using Windows Uses A Flat Memory Model
Each process started on x86 version of Windows uses a flat memory model that ranges from 0x00000000 – 0xFFFFFFFF. The lower half of the
memory, 0x00000000 – 0x7FFFFFFF, is reserved for user space code.While the upper half of the memory, 0x80000000– 0xFFFFFFFF, is reserved for
the kernel code. The Windows operating system also doesn't use the segmentation (well actually it does, because it has to), but the segment table
contains segment descriptors that use the entire linear address space. There are four segments, two for user and two for kernel mode, which
describe the data and code for each of the modes. But all of the descriptors actually contain the same linear address space. This means they all point
to the same segment in memory that is 0xFFFFFFFF bits long, proving that there is no segmentation on Windows systems. Let's execute the "dg 0
30" command to display the first 7 segment descriptors that can be seen on the picture below: Notice that the 0008, 0010, 0018 and 0020 all start
at base address 0x00000000 and end at address 0xFFFFFFFF: They represent the data and code segments of user and kernel mode. This also proves
that the segmentation is actually not used by the Windows system. Therefore we can use the terms"virtual address space" and "linear address space"
interchangeably, because they are the same in this particular case. Because of this, when talking about user space code being loaded in the virtual
address space from 0x00000000 to 0x7FFFFFFF, we're

Major Elements Of Memory Management
D.Major elements of memory management
Linux operating system is using virtual memory to support programs running in the system. The virtual memory provides lots of optimal ways to
maximize the memory mapping and utilization. The virtual memory can allocate much more memory to processes than its actual physical memory size.
Linux provides virtual memory great support to allow the processes running in the system, such as mapping the process's memory to physical memory
(Arora, 2012).
There are two major important elements in memory management: virtual memory and demand paging. As discussed before, virtual memory plays a
powerful role to support the programs for memory needs which may more than the physical memory size. Virtual memory is a ... Show more content on
Helpwriting.net ...
In the process, page model plays a role as a flag with virtual/physical page frame number as identified number for mapping; in addition it also provides
access information such as read–only, or read–write, for access control.
E.Major elements of scheduling
The scheduling of Linux operating system is priority based scheduling. It is to make scheduling policies into the core of Linux which called Kernel for
multi–tasking processes. There are two different scheduling: real time and normal, for handling large data processes performance balance and
sharing CPU equally in the system. In the scheduling of Kernel, each process has a priority value which ranges from 1 to 139. 1 is the highest
priority level. 139 is the lowest priority level. The real time priorities range from 1 to 99 and the normal priorities range from 100 to 139. The smaller
number of priority value, the priority is higher. All real time programs have a higher priority than normal programs in the system. In Linux scheduling
is implemented by a class named sched_class (Seeker, 2013).
The purpose of this class is to handle the multi–tasking processes by scheduler skeleton and data algorithms. As discussed above, the priority value is
very important for the scheduling, so how the system set the priority in the Linux for assigning which is in higher priority? It depends on the types of the

Chapter 5 Of The Windows Internals Textbook
Windows Internals, Part 1, 6th ed, Chapter 5 Chapter 5 of the Windows Internals textbook written by Mark Russinovich, David Solomon and Alex
Ionescu covers Windows processes, threads, and jobs. This chapter goes over how processes are managed, describes the kernel mode and user
mode, and process blocks. One of the topics I am covering for my final is the similarities and differences between processes and threads in
Windows and FreeBSD so this source will help provide information about the properties of threads, processes and jobs in Windows and how they
are managed. Windows Internals, Part 2, 6th ed, Chapter 8 Chapter 8 of the Windows Internals textbook written by Mark Russinovich, David
Solomon and Alex Ionescu covers the Windows I/O system. This chapter goes over device drivers, I/O system components and features, and Plug
and Play. One of the topics I am covering for my final is the similarities and differences between the Windows and FreeBSD I/O system so this
chapter will assist me in explaining how the I/O system in Windows operates and unique factors that Windows has when it comes to I/O. Windows
Internals, Part 2, 6th ed, Chapter 10 Chapter 10 of the Windows Internals textbook written by Mark Russinovich, David Solomon and Alex Ionescu
covers Windows memory management. This chapter goes over virtual address space, copy–on–page writing, and paging. One of the topics I am
covering for my final is the similarities and differences between memory management in Windows

The Operating System ( Os )
The operating system (OS) has two view–points it provides services to:
1.User view
2.System view
User view: From user point of view operating system should be convenient and easy to use and interact with. It should be better performance vice.
Following are the two, some of important services provided by the operating system that are designed for easy to use computer system.
a)Program Execution: The major purpose of the operating system is to allow the user to execute programs easily. The operating system provides an
environment where users can conveniently run or execute programs and as well as able to end programs. Running programs involves memory
management (the allocation and de–allocation memory), device management, processor ... Show more content on Helpwriting.net ...
sensors, motion detectors etc.). Almost all programs require some sort of input and produces output. This involves the use of I/O operations. The
operating system hides the low level hardware communication for I/O operations from the user. User only specifies device and the operation to
perform, and only see that I/O has been performed (i.e. choosing one of the printer in office for printing service). For security and efficiency, user level
programs cannot control I/O operations. Therefore, the operating system must facilitate these services.
System view: From a system point of view operating system should allocate resources (use system hardware) in a fair and efficient manner. This
includes algorithms for CPUs scheduling and avoiding deadlocks etc. Following are two services for system hardware.
a)Resource Allocation: Modern computers are capable of running multiple programs and can be used by multiple users at the same time. Resources
allocation/management is the dynamic allocation and de–allocation by the operating system of (hardware) including processors, memory pages, and
various types of bandwidth to the computation that compete for those resources. Operating system kernel, in which all these functions, algorithms and
services reside, is in charge of taking care of resource allocation. The objective is to allocate resources so as to optimise responsiveness subject to the
finite resources available.

Midterm 2 Solutions Essay
CSCI 4061: Introduction to Operating Systems Fall 2008 Mid–Term Exam II Sample Solution NAME: STUDENT ID: General Instructions: Write your
name and student ID clearly above. You have 1 hour and 15 minutes to write the exam. No extra time will be given. There are 4 questions in the
exam, all with subparts. The questions combine for a maximum of 100 points. You must write your answers clearly in the space provided for each
question. You might use the backside of each page, as well as any additional sheets as required. If you are using additional space, you must clearly
label the question no. that you are answering. Any loose sheets must have your name and student ID written clearly. The exam is open book/open
notes, however,... Show more content on Helpwriting.net ...
The threads run concurrently, and their order of execution or the interleaving of their instructions is non–deterministic. For each of the following, show
how you will modify the code for thread i using semaphores to achieve the desired execution behavior. Note: For each semaphore that you use,
show where you will add its wait and/or signal operations, and also specify its initial value. Also Note: You can use pseudocode instead of POSIX
/C syntax for your solution. (a) (6 pts) Have each thread execute its code (both foo and bar) in a mutually exclusive manner. The order in which the
threads execute does not matter. Ans: This is a classical critical section problem, and we basically need a mutex lock here. Recall that a semaphore
with initial value of 1 can be used identically to a mutex lock (since it allows only 1 thread to be in the critical section at a time). So the solution is
as follows. Declare a global semaphore: semaphore sem=1; Code for thread i: wait(sem); foo(i); bar(i); signal(sem); (b) (12 pts) Have each thread
execute foo in a mutually exclusive manner, but allow upto 5 of them to execute bar concurrently. The order in which the threads execute does not
matter. Ans: Here, executing foo is again a classical critical section problem, that can be solved similar to part (a). However, executing bar allows
multiple threads to be in the critical section, and this can be achieved by initializing the semaphore

Windows Vs Linux Vs. Linux
1.Compare between this two very popular Operating Systems, Windows VS Linux in terms of :
a.Memory management
1.Focus on how both operating systems handle their memory management especially on virtual memory. To support your research, you may include
relevant scenario of how memory being access.
WINDOWSLINUX
Your computer's RAM has been combined with temporary space byvirtual memory on your hard disk. Virtual memory moves data from RAM to a
space called a paging file when RAM runs low. Moving data to and from the paging file frees up RAM so your computer can complete its work. The
more RAM your computer has, the faster your programs will generally run. You might be tempted to increase virtual memory to compensate if a lack
of RAM is slowing your computer. However, your computer can read data from RAM much more quickly than from a hard disk.
Non–paged Pool
On (Russinovich, 2009)when the system can't handle page faults,the kernel and device drivers use non–paged pool to store data that might be accessed.
The kernel enters such a state when it executes interrupt service routines (ISRs) and deferred procedure calls (DPCs), which are functions related to
hardware interrupts. Page faults are also illegal when the kernel or a device driver acquires a spin lock, which, because they are the only type of lock
that can be used within ISRs and DPCs, must be used to protect data structures that are accessed from within ISRs or DPCs and either other ISRs or
DPCs or code executing

Virtual Memory Management For Operating System Kernels 5
CSG1102
Operating Systems
Joondalup campus
Assignment 1
Memory Management
Tutor: Don Griffiths
Author: Shannon Baker (no. 10353608)
Contents
Virtual Memory with Pages2
Virtual Memory Management2
A Shared Virtual Memory System for Parallel Computing3
Page Placement Algorithms for Large Real–Indexed Caches3
Virtual Memory in Contemporary Microprocessors3
Machine–Independent Virtual Memory Management for Paged Uniprocessor and Multiprocessor Architectures4
Virtual Memory with Segmentation4
Segmentation4
Virtual Memory, Processes, and Sharing in MULTICS4
Virtual Memory5
Generic Virtual Memory Management for Operating System Kernels5
A Fast Translation Method for Paging on Top of Segmentation5

References6
Virtual Memory with Pages
Virtual Memory Management
(Deitel, Deitel, & Choffnes, 2004)
A page replacement strategy is used to determine which page to swap when the main memory is full. There are several page replacement strategies
discussed in this book, these methods are known as Random, First–In–First–Out, Least–Recently–Used, Least–Frequently–Used and
Not–Used–Recently. The Random strategy randomly selects a page in main memory for replacement, this is fast but can cause overhead if it selects a
frequently used page. FIFO removes the page that has been in the memory the longest. LRU removes the page that has been least recently accessed,
this is more efficient than FIFO but causes more system overhead. LFU replaces pages based on

The Proposed Solution1 Builds A Framework For Add Static...
The proposed solution1 builds a framework to add static probes. This solution was designed and implemented by me as part of VProbes[7] project
during summer internship 2014 at VMware, inc. The solution in this paper covers a high level overview of the framework. It builds on top of the
existing VProbes[7] design1. User space applications or the existing kernel source can add static probes using this framework. The paper
describes adding static probes in a user space application to keep the explanation simple. Figure 1 shows a simple user code. The application contains
two probe points defined viz. FuncEntry and FuncExit. These are static probes which are added by the developer. The probe points are expanded in a
macro which is defined in the header file probes.h. Each of these probe points are declared as a volatile integer variable. However, these integer
variables are declared in a separate section in the ELF file as shown in Figure 2. Thus all the defined probe points are part of new section called
probes_uwsection. The probe points are padded with a name called "PROBE_" and "_PROBE" to avoid name mangling issue in C++. Hence, after
pre–processing stage, every probe name is padded. The application is compiled and loaded. During application load in the kernel, the binary is
intercepted at the ELF loader. In the ELF loader, the binary is checked for the presence of the new section probes_uwsection. If the new section exists,
all the probe points declared in the new

Scalable Cache Coherence Protocols Are Essential For...
Abstract
Scalable cache coherence protocols are essential for multiprocessor systems to satisfy the requirement for more dominant high–performance servers
with shared memory. However, the small size of the directory cache of the increasingly bigger systems may result in recurrent directory entries
evictions and, consequently, invalidations of cached blocks that will gravely corrupt system performance. According to prior studies, only a single
core accesses a considerable fraction of data blocks, so it is needless to monitor these in the directory structure. Using the technique of uniprocessor
systems and deactivating their consistency protocol is the best way to identify those private blocks actively. The directory caches will stop the tracking
of a substantial amount of blocks after the deactivation of the protocol, which will minimize their load and enhance their adequate size. The proposal
only needs minor changes because the operating system collaborates in finding the private blocks.
There are two fundamental contributions to the study. The first is to reveal that the classification of data blocks at block level assists to identify
significantly more classified data blocks as compared to work in a few earlier studies of organizing the cache blocks at the granularity of page and
sub–page. The method minimizes the proportion of blocks in the directory necessary for tracking significantly in comparison to the same course
approaches of level classification. It, in turn,

Role Of The Frame Table And The Disk Map Data Structures
CH 8
1. In a 5–stage pipelined processor, upon a page fault, what needs to happen in hardware for instruction re–start?
When there is a page fault during fetching an instruction pipeline must be drained, so that the instructions which are already executing show be
finished first. After this we cater the page fault and restart instructions.
Otherwise if there is a situation that page fault occur during MEM operation the instructions which are in other states such as in instruction fetch,
instruction decode or execute can be condensed as they won't be making any changes to the registers. After this we can handle the page fault.
2. Describe the role of the frame table and the disk map data structures in a demand paged memory manager.
Frame tables are used as a reference as we can get to know that which frames are available and which are already taken and which process they are
allocated.
Whereas the disk map data structures are used to know about the frames which are being swapped from the disk and where they can be relocated again.
4. Describe the interaction between the process scheduler and the memory manager.
Process scheduler and memory manager these 2 ae codes which lie dormant when a user process is started. Sometimes, the supervisory timer interrupt
raises the process scheduler which take decisions that which tasks should be run on Central processing unit. When a process is running it keeps on
asking many read and write memory access in its logical address

Computer Systems Working Around Us
Today, as a society, we all seem to accept the trend of doing multiple things at the same time because of the limited amount of time we are given on
a daily basis. We find ourselves juggling many tasks at once; whether it is time with family, work, or even a favorite hobby, we all have to find time
to manage all of these things while maintaining some kind of balance. It can be very difficult today to find time to do all of these things and one way
to make it a lot easier is by using computers. While scientifically proven that it is impossible for our brains to do multiple tasks at the same time, we
still seem to try. But now that we have so many amazing mini computer systems working around us, we can now do the multi–tasking that our hearts
desire. Our computers can do many processes simultaneously, allowing us to do many things that we want at the same time. But how do these
computers handle all of these processes and applications at the same time? Well, in short, computer memory. To describe the way that memory works, I
will be explaining a few of the many components of computer memory and how it is managed. Memory management is the act of managing computer
memory. The topics that I will include in the paper will consist of the following: Dynamic memory allocation,Virtual memory, memory leaks and stale
references, fragmentation, large memory and cache systems.
The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to

Nt1310 Unit 1 Algorithm Report
Exploiting the tensor product structure of hexahedral elements expresses the volume operations as 1D operators. The details are presented in algorithm
ref{alg_hexvol}.
begin{algorithm}[h]
caption{Hexahedron volume kernel}
label{alg_hexvol}
KwIn{nodal value of solution $mathbf{u} = left(p, mathbf{v} right)$, volume geometric factors $partial (rst)/ partial (xyz)$, 1D derivative
operator $D_{ij} = partial hat{l}_j /partial x_i$, model parameters $rho, c$}
KwOut{volume contributions stored in array $mathbf{r}$}
For{each element $e$}
{
For{each volume node $x_{ijk}$} { Compute derivatives with respect to $r,s,t$ $$frac{partial mathbf{u}}{partial r} =
sum_{m=1}^{N+1}D_{im} mathbf{u}_{mjk} qquad frac{partial mathbf{u}}{partial s} = sum_{m=1}^{N+1}D_{jm} mathbf{u}_{imk}
qquad frac{partial mathbf{u}}{partial s} = sum_{m=1}^{N+1}D_{km} mathbf{u}_{ijm}$$ Apply chain rule to compute $partial mathbf{u}
/partial x, partial mathbf{u}/partial y, partial mathbf{u}/partial z$ $$frac{partial mathbf{u}}{partial x} = frac{partial mathbf{u}}{partial r}
frac{partial r}{partial x} + frac{partial mathbf{u}}{partial s} frac{partial s}{partial x} + frac{partial mathbf{u}}{partial t} ... Show more
content on Helpwriting.net ...
Revisiting figure ref{GLNodes}, we notice that the SEM nodal points already contain the surface cubature points while the GL nodes do not.
Therefore, the SEM implementation is able to utilize the nodal values to compute the numerical flux, while the GL implementation requires additional
interpolations. In algorithm ref{alg_hexsuf}, we present the procedure of the hexahedron surface kernel. In both implementations, the solution values
on the surface cubature points are pre–computed and stored in array texttt{fQ}. The lines and variables marked with GL/SEM are the processes only
needed by the GL/SEM implementation

What Are The Advantages And Disadvantages Of Operating System
INTRODUCTION
The operating system is the most important program that runs on a computer. It is the component of system software in a program. It manages the
computer hardware and software . The operating system is a component of the system software in a computer system.
Operating system performs the following operations .
*recognizes the input from the keyboard or mouse
*sends output to the monitor
*keeps track of files and directories on the disk
*controls the peripheral devices such as disk drives and printers
Types of operating system 1)single user operating system
It Provides a platform for only one user at a time. They are popularly associated with Desk Top operating system which run on standalone systems
where no ... Show more content on Helpwriting.net ...
When computers in a group work in cooperation, they form a distributed system.
4)Embedded operating system
This type of operating system is used in embedded computer systems. It is operated on PDAs with less autonomy. It is compact and efficient to design .
5)Real–time operating system
A real–time operating system is an operating system that guarantees to process events or data within a certain short amount of time.
6)Library operating system
A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of
libraries.
Structure of operating system
The structure of OS consists of 4 layers:
1)Hardware It is the collection of physical elements that constitutes a computer system like CPU ,I/O devices

Nt1310 Unit 3 Memory Segmentation
Question 1 1.Memory segmentation is the division of a computer's primary memory information into sections. Segments are applied in object records
of compiled programs when linked together into a program image and when the image is loaded into the memory. Segmentation sights a logical
address as a collection of segments. Each segment has a name and length. With the addresses specifying both the segment name and the offset within
the segment. Therefore the user specifies each address by two quantities: a segment name and an offset. When compared to the paging scheme, the
user specifies a single address, which is partitioned by the hardware into a page number and an offset, all invisible to the programmer. Memory
segmentation is more visible

The Development Of Drivers For Virtual Machines
I. Introduction to the topic This paper will be analyzing the development of drivers for virtual machines, as well as how virtual machines access host
hardware. Topics covered will include what interest what interest I/O driver virtualization holds for the computer information science field, a general
overview of virtualization, I/O hardware virtualization, and virtualization of I/O drivers.
II. Why the topic is of interest
Due to increased efficiency in Central Processing Units, most computers today are not used to their full potential. In fact, time interrupt handlers are
issued as wait time, thus eating up CPU clock cycles. Virtualization gave the opportunity for multiple x86 Operating Systems to run on one machine. As
CPU's were ... Show more content on Helpwriting.net ...
CPU, memory and resources are divided amongst the OSes by the Virtual Machine Monitors, where the Virtual Machine resides. The Virtual Machine
is a software abstraction that will behave as though it is a complete machine, with virtual hardware resources, RAM, and I/O hardware [1]. There are
two main approaches to virtualization: hosted architecture, and hypervisor architecture. In hosted architecture, the encapsulation layer is installed in the
form of an application on the Operating System, while the hypervisor architecture involves the installing of the encapsulation layer, or hypervisor, on a
clean system, which gives direct access to the system's resources [2].
The issue of virtualization is that the virtualized OSes do not have full access to hardware resources and memory. They expect to execute within a
high privilege level. The VMM is run in this high layer, while the OS is moved to the user level, above the application level. This change in privilege
requires costly saving and restoring, and system calls can lead to some CPU cache loss. Instead, a translation look–aside buffer, or TLB, is used upon
VMM entry and exit to cache physical and virtual address translation [3]. Because different privilege levels also effect semantics, binary translation is
used to make up for the move. Three possibilities exist to allow virtualization: full virtualization with binary translation,

Computer Science : Memory Management
Memory Management
Navid Salehvaziri
Virginia International University Abstract
Memory management is a field of computer science that involves the act of managing computer memory to use it more efficient. That means how the
computer allocate portion of memory to programs at different levels of priority to make faster program execution regard to memory space limitation.
There are many techniques that are developed to reach this goal at many levels. This article try to introduce memory management levels and techniques.
Especially in this article, I want to focus at of memory management of operation system level and its techniques like virtual memory that is one of the
common technique that is used by many operation system to boost overall system performance. Memory Management
Introduction
Memory management is a technique that is used by computer system to allocate a limited amount of physical memory to processes of running user
applications and operation system in a way of boost and optimize computer performance. Memory management techniques usually are deployed at three
level of computer system that are:
1.Hardware memory management.
2.Operating system memory management.
3.Application memory management.
In most computers all of these three level techniques are used to some extent. These are described in more details below.
Hardware memory management
Memory management at the hardware level is concerned with the physical devices that actually store data and programs

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