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Why is virtual memory used even when sufficient RAM is available?
NikitaDurgude
Because there is no such thing as "sufficient RAM." You could have 128GB of RAM in your computer and eventually you are going to run a process that needs more RAM than you have. In the old days before virtual memory existed, your computer just crashed when that happened. These days, your machine just goes to disk.
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∙ 13y ago
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Why temporary memory is required for computer even though permanent is available?
Temporary memory is used to store program and applications that are being used at the time and allows for computing to be much faster. After the program closes the memory is no longer needed. there are two types RAM and Virtual Memory. RAM is a separate card and stands for Random Access Memory. Virtual Memory is space reserved on the Hard drive for the same purpose. By far the most efficient type is RAM as it is much faster than Virtual Memory and doesn't take Hard drive space al though for a modern computer both are needed for efficient performance.
What is a good Virtual Office program?
Regus has a wonderful virtual office available, they even have a free 30 day trial.
What is virtual memory-?
When dealing with computers, there are typically two types of memory. "Real" or "physical" memory is the same thing as RAM. They usually come as cards that you can install into slots on your computer's motherboard. "Virtual" memory, also known as "swap space" or (in Windows) a "paging file" is a dedicated partition or (in Windows) a file on your hard drive that acts like physical memory does. Even though both types of memory do the same thing (that is, storing things temporarily for easy access), physical memory is substantially faster than the typical hard drive. Don't consider virtual memory a replacement for RAM, but more of a complement - to catch the overflow, if you will.
Why are page files used?
On a 32-bit system it is only possible to address a maximum of 2^32 bytes of memory (4,294,967,296 bytes which is 4 gigabytes). Memory is allocated in contiguous blocks such that if your program requires x bytes of memory, a block of x contiguous bytes must be available to meet the allocation request. If there is no single block large enough to meet the required allocation, you will get an out of memory error, even if there's more than x bytes of physical memory available in total. To avoid these problems, we use virtual memory. If there is no single block available to meet an allocation, existing allocations can be temporarily moved to a page file, thus freeing up the physical memory. When memory that has been paged out is required, other allocations can be paged out to allow the required memory to be paged in. Given that the contents of memory are swapped to and from the page file, the page file is often called a swap file. Data that was paged out of one physical address may be paged in to a completely different physical address. However, the virtual address does not change; the memory manager performs the translation between the physical and virtual addresses. This makes it possible for a 32-bit system to operate with a full complement of 4 gigabytes of memory even when the system has less than 4 gigabytes of physical memory installed. 64-bit systems allow us to address 18,446,744,073,709,551,616 bytes of memory which is far more memory than physically exists on the planet! For practical reasons, we can only use a small fraction of the full address space, however page files and virtual memory make it possible to use far more addresses than might be physically available.
What is an advantage of loading an application entirely into RAM rather than loading part of that application into virtual memory?
CPU works directly with the RAM and any memory i/o on the RAM by the CPU is a solid state operation where no mechanical devices are involved. Therefore data operations with RAM are very fast. Virtual memory on the other hand has a portion on the RAM and a portion on the disc that cannot be accomodated in the RAM. This is because virtual memory is much larger than the RAM or even the address space available to the CPU. The virtual memory manager manages loading the data page from the disc and back. When a program needs a portion of data that is in the virtual memory, the virtual memory manager checks if the data is in a page that is already loaded on the RAM. If it is, then it simply hegabs the virtual memory address with the physical address on the RAM so that the program can access the memory. If the data is on a virtual address that is not on the RAM, Lol, the page that contains the portion of the data needed is loaded from the disc onto the RAM and placed in an empty slot that is available so that the virtual address could be converted to a physical address that is on the RAM. However the process of loading the page from the virtual memory involves seeking th page on the disc and loading it onto the ram. It may also involve making space available on the RAM if there is no empty slot found and for that a page needs to be unloaded from the RAM and putting it onto the disc which adds to another disc i/o operation. Thus explains why having the data accessed and operated on the RAM is much faster than Disc i/o. Now-a-days some computers do come with Hard disks that are completely electronic. Virtual memory operations will be much faster with such Hard disk drives. However the process of virtual to physical translation and paging shall still be required.
Is 6 GB the largest memory available in mp3 players?
No, 6 GB is no the largest memory capacity available for MP3 players. Apple iPods come in 8GB, 16GB, 32GB and 64GB. You can probable even special order one that has more memory.
Does a video card with ddr2 memory work on a mainboard with ddr memory?
assuming everything else is compatible, the memory is not an issue. many graphics card have ddr4 and ddr5 memory which isn't even available as RAM yet.
Describe How virtual memory works?
Virtual memory is a special file on the harddisk that the operating system can swap pages of physical RAM back and forth with to allow more programs than fit in physical RAM to run on the machine at the same time. For example on the computer I am writing this on right now the installed physical RAM is only 1GB, but the virtual memory file is about 50GB. Thats a lot more resident programs and data than the machine could support without the virtual memory!
What are the use of destructor in a class?
Destructors are used to free memory taken by classes, in order to make memory available for other applications without restarting your application or even whole environment.
Explain how it is possible that two programs that are together are much larger than a physical memory can both be executed in a virtual memory?
In a virtual memory system applications are not directly loaded into physical memory. Every process is assigned a virtual and private address space of 2GB. When an application is loaded it is mapped into this virtual space. When the application runs the code is copied from disk to RAM only when it is needed. Most applications contain code that is rarely accessd and there is no need or benefit in having this in RAM all the time. After code has been copied to RAM it will be retained for future use, often even after the application has closed. If this memory is needed for more importan uses it is immediately available as the data it contains can be reloaded from disk if needed. Using this method only frequently accessed data is in memory with the remainder kept on disk. This entire process is handled by the system and is totally transparent to applications. Note: When aplication code must be released from memory it is NOT copied to the pagefile as many uninformed sources have claimed. There is no need for this as this code is hardley ever modified and can simply be reloaded from the original files. Only data that has been modified is copied to the pagefile.
What is the purpose of virtual memory?
"Virtual" memory is computer memory that exists on a fixed media and non-volitile storage device of some kind -- a hard drive, or a solid state drive -- which is used, mostly, for overflow from, or swapping things in and/or out of, regular Random Access Memory (RAM). The computer comes with three kinds of memory in it: Read-only Memory (ROM), Random Access Memory (RAM), and the "virtual" memory that's created by the operating system on a hard drive or solid state drive. Hard drives, and/or solid state drives, in and of themselves, are not considered "memory." They're considered mass storage. However, once the operating system is up and running on the computer, and has allocated parts of itself, and of the various programs that are running, into RAM; and has also allocated a certain amount of RAM for calculating and doing things, then it will also allocate a little bit of one of the mass storage devices -- usually a hard drive, but on some of the newer machines with solid state drives in them, it can also be on that -- for what's called "virtual" memory, which is mostly used for RAM overflow... more specifically, for swapping things in and out of RAM. The computer reads from ROM (usually the BIOS and CMOS chips) at startup so that it even knows that it's a computer; and then, from there, what it has connected to it, and how to use it all. Then, once the computer has fully booted-up, the operating system loads parts of itself (and some other things) into RAM, and then it allocates part of mass storage as "virtual memory." As RAM starts getting full, the operating system will take the least-used things in RAM and will throw 'em down onto the part of the mass storage device that has been allocated as "virtual" memory. Then, if anything in virtual memory becomes needed up in RAM, again, the operating system will go get it and pull it back up into RAM. Virtual memory, then, is mostly used as "swap" space. It is not, then, actual "memory," per se; but it certainly functions like it. Virtual memory is also slower than regular RAM: Data cannot possibly be put onto, or pulled from, the "virtual" memory part of a hard drive full of moving parts as fast as it can be moved around RAM, itself. Even a solid state drive, which is a little like RAM in the sense that it's an integrated circuit with no moving parts, is not as fast as RAM. But the operating system knows how to keep things moving, and to only swap things down into virtual memory that really and truly won't be needed as much or as often or as quickly. The virtual memory management parts of most operating systems is pretty sophisticated. So, then, the answer to the question, "what is the purpose of virtual memory," is that virtual memory (which is always a part of a mass storage device, allocated by the operating system) is primarly used to swap things in and out of RAM so that said RAM won't get so clogged-up and bogged-down. When one purchases a computer, one reads certain specs about it. For example... The "processor" (or CPU) may be "dual core" and three-point-something gigahertz (GHz) in speed; or, The memory (or RAM) will be 4, 6, 8, 12 or 16 (sometimes more, sometimes less) gigabytes (GB) in size; or, The hard drive (mass storage) will be 500 to 750 gigabytes (GB) (or even one terrabyte, or larger) in size; and, sometimes, There could also, optionally, be a solid state drive (also considered mass storage) of 32 or 64 GB. "Virtual" memory is always allocated by the operating system from space on either or both of the hard drive or solid state drive mass storage devices; and said operating system then "swaps" things to/from RAM down to/from the allocated "virtual" memory; thereby keeping RAM from becoming cluttered and slow.
What can allow people to settle and even grow crops in the desert?
Water is the main factor. If sufficient water is available, people can live and farm in an area of desert.
