Prefix is a way of installing a Gentoo system in a non-standard location, designated by a 'prefix', on a preexisting system.

https://wiki.gentoo.org/wiki/Project:Prefix

a guide or (some kind) of special advanced recipe on how to configure EVERYTHING in a special way.
lots of obscure stuff. lots of regular stuff too. #heavyreading #mildlyinteresting #advanced

PGO flag enables theoretical performance optimizations based on a profile done by the package maintainer.

"In this case, when you enable those use flags, you download the profile file provided by the developers and use them automatically in the process." https://www.reddit.com/r/Gentoo/comments/18scsxu/how_to_apply_pgo/

but compile time is much longer.

the specs for it is a windows 8.0 eara intel Pentium cpu 3.9 gigs of ram , and windoes takes ~50% of ram . if so what desktop/tiling window manager should i emerge

updating processor firmware

This guide shows you how to set up and use GPM (the General Purpose Mouse server) from within a command line interface. This is especially useful for new Gentoo installations or for systems that cannot or do not use an X server.

https://packages.gentoo.org/packages/www-servers/apache

https://packages.gentoo.org/packages/dev-lang/php

https://packages.gentoo.org/packages/net-misc/curl

https://packages.gentoo.org/packages/media-video/ffmpeg

https://packages.gentoo.org/packages/media-video/vlc

https://packages.gentoo.org/packages/media-sound/pulseaudio

https://packages.gentoo.org/packages/www-client/firefox

https://packages.gentoo.org/packages/media-gfx/imagemagick

https://packages.gentoo.org/packages/sys-devel/gcc

1. emerge -DuN --with-bdeps=y sys-kernel/gentoo-sources
2. eselect kernel list ; eselect kernel set 2
3. cd /usr/src/linux ; pwd -P
4. uname -r ; ls /boot | grep config
5. cp /boot/config-3.14.14-gentoo /usr/src/linux/.config
6. cd /usr/src/linux ; make oldconfig
7. make menuconfig (optional)
8. make -j5
9. make modules_install; make install
10. update grub or lilo config to point to new kernel version.

toggles additional functionality for software or removes it.

/etc/portage/env and /etc/portage/package.env are used for modifying Portage's environmental variables, such as those specified in the /etc/portage/make.conf file, on a per-package basis.

The /etc/portage/env directory contains files that have the same syntax as make.conf. The filename will be used as the key to override settings.
The /etc/portage/package.env file describes which of these files will be used on a per-package basis.

/etc/portage/sets is an optional directory that is used to create user defined package sets. For each file in /etc/portage/sets, a package set is created, defining a one-to-many relationship between a set name and an arbitrary group of package atoms. User-defined set names correspond to the name of the file. Each file should contain a list of package atoms and nested package sets, one per line.

What is the difference between this community and the one at /c/gentoo? If both are about the Linux distribution, would it not be better for one of them to be removed (if not somehow merging them)?