Memtest86+

is [[Article description::memory test software based on the commercially available (from Passmark) memtest86 program.]]

There are multiple versions of memtest with similar names. Gentoo provides access to three in its main Portage repository.

Use n memtest86.com, in particular the section "MemTest86 and MemTest86+" an or above for UEFI supported testing.

Use Memtest86 (non plus) v4 for the older legacy BIOS version.

There is also a different commercial binary memtest86-bin v9.3+ masked behind a LICENSE=Passmark-EULA. This wiki guide does not apply, but can be used, YMMV.

Prerequisites
Be sure (where the GRUB files are typically installed) is available before installing memtest86+! If is on a separate partition (which it WILL BE if the partitioning scheme in the Gentoo handbook was used for this Gentoo install), then be sure the mount command is run before the emerge section below:

If no errors are return then boot should be successfully mounted. Check by running the command without any arguments and parsing the output with :

Emerge
Install it through Portage with emerge:

GRUB2
For GRUB2 just run. As long as the package has been emerged, a configuration file has already been installed to :

GRUB legacy
Replace the  (question marks) in the file below with correct numbers for the system's boot partition:

LILO
For LILO, add this to the configuration file:

Then rebuild LILO's MBR entry:

Syslinux
Add this to the configuration file:

Usage
To use memtest86+ the system needs to be rebooted using the newly added boot item.

External resources

 * https://www.memtest86.com/ - Official commercial Passmark website.
 * https://www.pcworld.com/article/232640/memtest86.html - A PCWorld article describing the usefulness and features of memtest86+.