Memory discovery

Discovering the amount of memory is often even more practically important than discovering CPU features. It is required to plan application deployment, choose the size of a swap partition, and estimate whether you need to install more memory already.

However, the kernel interfaces for memory discovery are not as rich as those for discovering CPU features. For example, it is impossible to find out how many memory slots a system has, how many of them are used, and what the sizes of memory sticks installed in those slots using the kernel interface are alone. At least on some architectures, it is possible to obtain that information, but from the firmware rather than from the kernel, as we will see later in the dmidecode section.

Moreover, information from the kernel can be misleading for beginners who are unfamiliar with Linux kernel conventions. First, let us look at that information and then discuss how to interpret it.

First, we will look at the output of the...