A swap primer for dCore users with minimal Linux or no Tiny Core Linux experience.

Depending on intended use, a Linux swap partition or swap file is recommended for systems with < 1-2 GB RAM. Swap is especially useful on low RAM systems to import/update large extensions, run numerous/heavier applications, compile software or set up hibernation.

By default, dCore will seek and utilize any existing swap partition at boot. To confirm whether a swap partition is being utilized, run cat /etc/fstab, free -m and/or cat /proc/swaps, examples:

tc@box:~$ cat /etc/fstab | grep swap
/dev/sda5       none            swap     defaults             0 0 # Added by TC

tc@box:~$ free -m
             total       used       free     shared    buffers     cached
Mem:           500        484         15         73         37        267
-/+ buffers/cache:        179        320
Swap:          729          1        727

tc@box:~$ cat /proc/swaps
Filename                                Type            Size    Used    Priority
/dev/sda5                               partition       746984  0       -1

Setting up a swap partition during a fresh installation using fdisk is outlined in the Partition Hard Drive and Create Hard Drive File Systems sections of dCore Install from ISO to Hard Drive Without Pre-Existing Boot Loader. Systems with a pre-partitioned drive may find it easiest to use a Linux LiveCD that contains GParted. Alternatively set up a swap file, outlined below.

If a swap partition was not set up prior to the installation of dCore, it may be easiest to set up a swap file. From a graphic environment open Control Panel (cpanel) → Swapfile Tool (swapfile) and enter the desired mounted partition to utilize along with the desired swap file size. Then add the swapfile bootcode to the system's boot loader to activate upon reboot, example swapfile=sda1. To confirm the swap file is being used, reboot system and run cat /proc/swaps.

For more information regarding Tiny Core Linux boot codes review boot codes explained. The following swap related boot codes are available:

• swapfile (eg. swapfile=sda2) to use a swapfile.
• noswap to disable use of any swap partition(s).
• nozswap to disable compressed swap in RAM (zswap).

As outlined, dCore automatically seeks available swap partition(s) at boot. If using the swapfile boot code, a swapfile needs to be set up in advance. By default dCore uses compressed swap in RAM (zswap), which sets aside a block of RAM to use as compressed swap space, so systems with adequate RAM may not require dedicated swap. Review the Wikipedia zswap link above for more information, especially the CPU cycles vs I/O tradeoff. Actual system experimentation is recommended to determine which swap options or boot codes are required, if any. This Linux Swap File How To is a valuable resource for those who wish to manually create a swap file or experiment with swappiness.

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