As a result of this question, I was a bit confused.
After some research I found that swapping is enabled by default on Mac OS X. Swapping was furthermore introduced in Windows 3.0, so I believe it is also enabled by default. Is this correct?
Is swapping in general disabled on common Linux distributions, e.g. Ubuntu?
The ability to swap in Linux is dependent on configuration of a disk partition or a sufficiently large (specially formatted) file on an active mounted partition to operate. Generally when a system is semi-automatically installed there is one swap partition created, configured and put into the /etc/fstab file for use. OSX being a UNIX/Linux off-shoot is thus configured accordingly during its installation.
NOTE: Generally UNIX/Linux systems administrators DO create and configure swap space. Although if your system is using swap space there is usually something very wrong is happening and performance suffers.
Thus my answer is in general that swapping is enabled on common Linux distributions as a result of the creation, and configuration of swap space during installation.
Most OS installers including the Ubuntu/Debian installer will create and enable a swap partition if you select all of the default options in the installer, in particular if you use automatic/guided partitioning.
If you use manual partitioning at installation time or if you retain the partition table that already exists on the disk, then it's up to you whether you create a swap partition or not. If you create one and/or designate one, the installer will most likely enable it.
You can check /etc/fstab to see if a swap partition is configured. Look for an entry with type swap. If there is one configured, it should get enabled at boot time. Check /proc/swaps to see if it is really enabled.
Most current operating are multitasking and use virtual memory and therefore use swap. For example, this Linux question Why use swap when there is more than enough free space in RAM? and this OSX question Why would I disable swap file in Mac OS X?
Yes, most Operating systems will create a swap during default installation.
Yes, most operation systems will warn you / yell at you if you try to configure a system without SWAP (usually insisting on creating even a tiny one).
see Debian, Red Hat 7, Windows (64bits).
