Memory
Random-access memory (RAM /ræm/) is a form of computer data storage that stores data and machine code currently being used. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. Wikipedia
Paging is a memory management scheme by which a computer stores and retrieves data from secondary storage[a] for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. Paging is an important part of virtual memory implementations in modern operating systems, using secondary storage to let programs exceed the size of available physical memory. The Linux kernel supports a virtually unlimited number of swap backends (devices or files), supporting at the same time assignment of backend priorities. From the end-user perspective, swap files in versions 2.6.x and later of the Linux kernel are virtually as fast as swap partitions; the limitation is that swap files should be contiguously allocated on their underlying file systems. Wikipedia
Command free
FREE(1) User Commands FREE(1)
NAME
free - Display amount of free and used memory in the system
SYNOPSIS
free [options]
DESCRIPTION
free displays the total amount of free and used physical and swap mem‐
ory in the system, as well as the buffers and caches used by the ker‐
nel. The information is gathered by parsing /proc/meminfo. The dis‐
played columns are:
total Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
...pi@raspberrypi:~ $ free
total used free shared buff/cache available
Mem: 949580 449408 225500 38592 274672 409512
Swap: 102396 17156 85240
pi@raspberrypi:~ $ free -m
total used free shared buff/cache available
Mem: 927 429 228 38 269 408
Swap: 99 16 83
pi@raspberrypi:~ $Last updated