Thrashing can occur when total virtual memory, both RAM and swap space, become nearly full. I don’t recommend using a file for swap space unless absolutely necessary. Then the mkswap command is run to configure it as swap space. This is just a regular file that is created and preallocated to a specified size.
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A swap partition is just what its name implies-a standard disk partition that is designated as swap space by the mkswap command.Ī swap file can be used if there is no free disk space in which to create a new swap partition or space in a volume group where a logical volume can be created for swap space. By default, most Linux installations create a swap partition, but it is also possible to use a specially configured file as a swap file. Linux provides for two types of swap space.
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The total amount of memory in a Linux computer is the RAM plus swap space and is referred to as virtual memory.
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Those pages of memory swapped out to the hard drive are tracked by the kernel’s memory management code and can be paged back into RAM if they are needed. This frees up RAM and makes room for more data to be entered into your spreadsheet. The memory management program swaps enough of these relatively infrequently used pages of memory out to a special partition on the hard drive specifically designated for “paging,” or swapping. The kernel uses a memory management program that detects blocks, aka pages, of memory in which the contents have not been used recently. Without swap space available, you would have to stop working on the spreadsheet until you could free up some of your limited RAM by closing down some other programs. But suppose the spreadsheet you are working on grows when you add more rows, and that, plus everything else that's running, now fills all of RAM. If you start up programs that don’t fill that RAM, everything is fine and no swapping is required. The primary function of swap space is to substitute disk space for RAM memory when real RAM fills up and more space is needed.įor example, assume you have a computer system with 8GB of RAM. Free online course: RHEL Technical Overview.The second type of memory in modern Linux systems is swap space. During the boot process, a computer copies specific operating system programs, such as the kernel and init or systemd, and data from the hard drive into RAM, where it is accessed directly by the computer’s processor, the CPU. The CPU (central processing unit) cannot directly access the programs and data on the hard drive it must be copied into RAM first, and that is where the CPU can access its programming instructions and the data to be operated on by those instructions. Magnetic media is nonvolatile the data stored on a disk remains even when power is removed from the computer. Hard drives are magnetic media used for long-term storage of data and programs.
RAM is volatile memory that is, the data stored in RAM is lost if the computer is turned off. Programs and data cannot be used by the computer unless they are stored in RAM. The first type, random access memory (RAM), is used to store data and programs while they are being actively used by the computer. There are two basic types of memory in a typical computer.