不稳定软件包有几种，
1，~amd64(~x86) keyword
这种情况说明make.conf中指明了关键字amd64，而不是~amd64关键字，这样所有标有~amd64关键字的软件默认都不会装上。
$ emerge -pv =vanilla-sources-2.6.16.62
These are the packages that would be merged, in order:
Calculating dependencies...
!!! All ebuilds that could satisfy"=sys-kernel/vanilla-sources-2.6.16.62" have been masked.
!!! One of the following masked packages is required to complete your request:
- sys-kernel/vanilla-sources-2.6.16.62 (masked by: ~amd64 keyword)
[...]
这是程度最轻的，~amd64表示该软件在amd64架构上尚不稳定，可以通过添加为该软件添加~amd64关键字来安装：
# echo"=sys-kernel/vanilla-sources-2.6.16.62 ~amd64" >>/etc/portage/package.keywords
# emerge -pv =vanilla-sources-2.6.16.62
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild N ] sys-kernel/vanilla-sources-2.6.16.62 USE="-build -symlink" 40,240 kB
Total: 1 package (1 new), Size of downloads: 40,240 kB
2，missing keyword
这种比表明该软件在该平台上还没有规范的测试过，不知是否可用。显然这样的软件一般是无法保障的。
# emerge -pv =vanilla-sources-2.6.27_rc6
These are the packages that would be merged, in order:
Calculating dependencies \
!!! All ebuilds that could satisfy"=sys-kernel/vanilla-sources-2.6.27_rc6" have been masked.
!!! One of the following masked packages is required to complete your request:
- sys-kernel/vanilla-sources-2.6.27_rc6 (masked by: package.mask, missing keyword)
(2.6.27_rc6) [m]~*2.6.27_rc6
这时需要在该软件的ebuild中加入相应的平台关键字，在文件/usr/portage/sys-kernel/vanilla-sources/vanilla-sources-2.6.27_rc6.ebuild中加入~amd64：
KEYWORDS="~alpha ~arm ~hppa ~ia64 ~ppc ~ppc64 ~sparc ~x86 ~amd64"
再
# ebuild /usr/portage/sys-kernel/vanilla-sources/vanilla-sources-2.6.27_rc6.ebuild digest
3， package.mask
这种情况的软件的稳定程度介于第一种和第三种之间，下面接着第二的例子再emerge一下：
# emerge -pv =vanilla-sources-2.6.27_rc2
These are the packages that would be merged, in order:
Calculating dependencies -^C
Exiting on signal 2
Gentoo-F312-64 example # emerge -pv =vanilla-sources-2.6.27_rc6
These are the packages that would be merged, in order:
Calculating dependencies \
!!! All ebuilds that could satisfy"=sys-kernel/vanilla-sources-2.6.27_rc6" have been masked.
!!! One of the following masked packages is required to complete your request:
- sys-kernel/vanilla-sources-2.6.27_rc6 (masked by: package.mask, ~amd64 keyword)
这时出现了package.mask, ~amd64 keyword，后者第1点已经说到了，对于package.mask，只需：
# echo"=sys-kernel/vanilla-sources-2.6.27_rc6" >>/etc/portage/package.unmask
就可以了，按照第一点，还要接着：
# echo"=sys-kernel/vanilla-sources-2.6.27_rc6 ~amd64" >>/etc/portage/package.keywords
这样该软件就ok了：
# emerge -pv =vanilla-sources-2.6.27_rc6
These are the packages that would be merged, in order:
Calculating dependencies... done!
[ebuild N ] sys-kernel/vanilla-sources-2.6.27_rc6 USE="-build -symlink" 62,377 kB
