NAME: NKETIA CONSTANCE
Virtual Machine is a completely separate individual operating system installation on your usual operating system. It is implemented by software emulation and hardware virtualization.
Virtual machine is a software implementation of a physical machine – computer – that works and executes analogically to it. Virtual machines are divided in two categories based on their use and correspondence to real machine: system virtual machines and process virtual machines. First category provides a complete system platform that executes complete operating system, second one will run a single program.
Frequently multiple virtual machines with their own OS’s are used in server consolidation, where different services are run in separate virtual environments, but on the same physical machine.
The main advantages of virtual machines:
- Multiple OS environments can exist simultaneously on the same machine, isolated from each other;
- Virtual machine can offer an instruction set architecture that differs from real computer’s;
- Easy maintenance, application provisioning, availability and convenient recovery.
The main disadvantages:
- When multiple virtual machines are simultaneously running on a host computer, each virtual machine may introduce an unstable performance, which depends on the workload on the system by other running virtual machines;
- Virtual machine is not that efficient as a real one when accessing the hardware.
- Virtualization brings you a number of advantages – centralizing network management, reducing dependency on additional hardware and software, etc. But as it is always the case, it has certain shortcomings too. CITATION Elt18 l 1033 32-BIT & 64-BIT OPERATING SYSTEM
Here are some of the enormous benefits to making the jump to a 64-bit system:
You can rock radically more RAM: How much more? 32-bit versions of Windows (and other OSes for that matter) are limited to 4096MB (or 4GB) of RAM. 64-bit versions are theoretically capable of supporting a little over 17 billion GBs of RAM thanks to that spacious register system we talked about earlier. Realistically, Windows 7 64-bit Home editions are limited (because of licensing issues, not physical limitations) to 16GB of RAM and the Professional and Ultimate editions can rock up to 192GB of RAM.
You’ll see increased efficiency: Not only can you install more RAM in your system (easily as much as your motherboard can support) you’ll also see more efficient use of that RAM. Because of the nature of the 64-bit address system in the register and how Windows 64-bit allocates memory you’ll see less of your system memory chewed up by secondary systems (like your video card).
Your computer will be able to allocate more virtual memory per process: Under 32-bit architecture Windows is limited to assigning 2GB of memory to an application. Modern games, video and photo editing applications, and hungry applications like virtual machines, crave large chunks of memory. Under 64-bit systems they can have, brace yourself for another big theoretical number, up to 8TB of virtual memory. On top of the more efficient use and allocation of memory, applications optimized for 64-bit operating systems, such as Photoshop and Virtualbox, are super fast and take full advantage of the spaciousness of the processor and memory afforded to them.
You’ll enjoy advanced security features: Windows 64-bit with a modern 64-bit processor enjoys additional protections not available to 32-bit users. These protections include the aforementioned hardware D.E.P., as well as Kernel Patch Protection that protects you against kernel exploits, and device drivers must be digitally signed which cuts down on the incident of driver-related infections.
The list of shortcomings that come with adopting a 64-bit operating system
You can’t find 64-bit drivers for older but critical devices on your system: This one is a serious deal killer, but the good news is that it’s not as big a problem as it used to be. Vendors almost universally support 64-bit versions of the latest operating systems and devices. If you’re running Windows 8 or 10 and using hardware manufactured in the last five or so years, you shouldn’t have any trouble with hardware drivers. If you’re running Windows 7 or previous—or using very old hardware—you might have less luck. Have an expensive sheet-fed scanner from 2003 that you love?
Too bad. You’re probably not going to find any 64-bit drivers for it. Hardware companies would rather spend their energy supporting new products (and encouraging you to buy them) than supporting older hardware. For small things that are easily replaced or need to be upgraded anyway, this isn’t a big deal. For mission critical and expensive hardware, it’s more important. You’ll have to decide for yourself if the upgrade cost and trade-offs are worth it.
Your motherboard doesn’t support more than 4GB of RAM: Although rare, it’s not unheard of to have a motherboard that will support an early 64-bit processor but not support more than 4GB of RAM. In this case you’ll still get some of the benefits of a 64-bit processor but you won’t get the benefit that most people crave: access to more memory. If you’re not buying bleeding edge parts, however, hardware has gotten so cheap lately that it might be time to retire the old motherboard and upgrade at the same time you’re upgrading your OS.
You have legacy software or other software issues to deal with: Some software doesn’t make the transition to 64-bit smoothly. While 32-bit apps run just fine on 64-bit Windows, 16-bit apps will not. If by some chance you’re still using a really old legacy app for something, you’ll need to either virtualize it or forgo an upgrade CITATION How18 l 1033 BUFFER OVERFLOW
A buffer overflow occurs when a program or process attempts to write more data to a fixed length block of memory, or buffer, than the buffer is allocated to hold.
Since buffers are created to contain a defined amount of data, the extra data can overwrite data values in memory addresses adjacent to the destination buffer unless the program includes sufficient bounds checking to flag or discard data when too much is sent to a memory buffer CITATION Tec18 l 1033 A Buffer Overflow Attack is an attack that abuses a type of bug called a “buffer overflow”, in which a program overwrites memory adjacent to a buffer that should not have been modified intentionally or unintentionally. Buffer overflows are commonly associated with C-based languages, which do not perform any kind of array bounds checking. As a result, operations such as copying a string from one buffer to another can result in the memory adjacent to the new (shorter) buffer to be overwritten with excess data.
When a buffer overflow occurs in a program, it will often crash or become unstable. An attacker attempting to abuse a buffer overflow for a more specific purpose other than crashing the target system, can purposely overwrite important values in the call stack of the target machine such as the instruction pointer (IP) or base pointer (BP) in order to execute his or her potentially malicious unsigned code. Operating system and software vendors often employ countermeasures in their products to prevent Buffer Overflow Attacks; particularly call stack and virtual memory randomization. Given the existence of such protective measures, Buffer Overflow Attacks have been rendered more difficult, although still possible to carry out CITATION Raded l 1033
Resource management is the dynamic allocation and de-allocation by an operating system of processor cores, memory pages, and various types of bandwidth to computations that compete for those resources. The objective is to allocate resources so as to optimize responsiveness subject to the finite resources available. Historically, resource management solutions have been relatively unsystematic, and now the very assumptions underlying the traditional strategies fail to hold. First, applications increasingly differ in their ability to exploit resources, especially processor cores. Second, application responsiveness is approximately two-valued for “Quality-Of-Service” (QOS) applications, depending on whether deadlines are met. Third, power and battery energy have become constrained. This talk will propose a scheme for addressing the operating system resource management problem CITATION Smi10 l 1033 References
- Eltima Software, “Serial Server / WHAT IS VIRTUAL MACHINE,” Ste 5 Horsford’s Business Centre, Long Point Road, Charlestown, Nevis • +1 360 312 7638 (CET) •, 2000-2018. [Online]. Available: http://www.serial-server.net/virtual-machine/. [Accessed 5 May 2018].
- How-To Geek, LLC All Rights Reserved, “What’s the Difference Between 32-bit and 64-bit Windows?,” 2006-2018. [Online]. Available: https://www.howtogeek.com/56701/htg-explains-whats-the-difference-between-32-bit-and-64-bit-windows-7/. [Accessed 5 May 2018].
- TechTarget, “buffer overflow,” TechTarget, 2000 – 2018. [Online]. Available: https://searchsecurity.techtarget.com/definition/buffer-overflow. [Accessed 5 May 2018].
- Radware Ltd., “Buffer Overflow Attack,” Radware Ltd., 2018 All Rights Reserved. [Online]. Available: https://security.radware.com/ddos-knowledge-center/ddospedia/buffer-overflow-attack/. [Accessed 5 May 2018].
- B. Smith, “Operating system resource management,” in IEEE, Atlanta, GA, USA, 19-23 April 2010.
Cite this essay
Virtual Machine. (2020, Jun 02). Retrieved from https://studymoose.com/virtual-machine-25171-new-essay