Twin directories of os:

[DIR]  ftp://ftp.tw.openbsd.org/pub/OpenBSD/src/gnu/usr.sbin/sendmail/include/sm/os/
[DIR]  ftp://ftp.tw.openbsd.org/pub/OpenBSD/src/gnu/lib/libstdc++/libstdc++/config/os/
[DIR]  ftp://ftp.di.uminho.pt/pub/centos/4.5/os/
[DIR]  ftp://ftp5.jp.freebsd.org/pub/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.jpix.ad.jp/pub/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.ar.freebsd.org/pub/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.kaist.ac.kr/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp12.freebsd.org/pub/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.heitec.net/repo/src/contrib/sendmail/include/sm/os/
[DIR]  ftp://ftp.heitec.net/repo/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp6.tw.freebsd.org/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://155.232.137.108/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.cse.buffalo.edu/mirror/BSD/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://208.209.50.19/pub/.vol02/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.informatik.rwth-aachen.de/pub/mirror/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp2.tw.freebsd.org/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.ncnu.edu.tw/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.cerias.purdue.edu/pub/os/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.lucky.net/pub/FreeBSD/development/FreeBSD-CVS/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.coe.ufrj.br/j/FreeBSD/local/cvs/src/contrib/libstdc++/config/os/
[DIR]  ftp://ftp.net.pulawy.pl/pub/linux/fedora_core/6/x86_64/os/
[DIR]  ftp://ftp.net.pulawy.pl/pub/linux/fedora_core/6/i386/os/
[DIR]  ftp://ftp.pslib.cz/pub/linux/fedora/linux/development/i386/os/
[DIR]  ftp://ftp.funet.fi/.m/mirrors2/ftp.redhat.com/pub/fedora/linux/development/x86_64/os/
[DIR]  ftp://ftp.funet.fi/.m/mirrors2/ftp.redhat.com/pub/fedora/linux/development/i386/os/
[DIR]  ftp://ftp.wicks.co.nz/pub/linux/dist/aurora/build-2.98/os/
[DIR]  ftp://ftp.wicks.co.nz/pub/linux/dist/aurora/build-2.0/sparc/os/
[DIR]  ftp://ftp.uci.edu/mirrors/fedora/linux/releases/9/Everything/i386/os/
[DIR]  ftp://ftp.mathematik.uni-marburg.de/pub/mirror/fedora/development/i386/os/
[DIR]  ftp://ftp.mathematik.uni-marburg.de/pub/mirror/fedora/development/x86_64/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Everything/ppc/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Everything/x86_64/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Everything/i386/os/
[DIR]  ftp://ftp.ps.pl/dsk0/Fedora/fedora-enchilada/linux/development/x86_64/os/
[DIR]  ftp://ftp.upjs.sk/pub/fedora/linux/development/x86_64/os/
[DIR]  ftp://ftp.ps.pl/dsk0/Fedora/fedora-enchilada/linux/development/i386/os/
[DIR]  ftp://ftp.muug.mb.ca/mirror/fedora/linux/development/i386/os/
[DIR]  ftp://ftp.upjs.sk/pub/fedora/linux/development/i386/os/
[DIR]  ftp://ftp.ps.pl/dsk0/Fedora/fedora-enchilada/linux/development/ppc/os/
[DIR]  ftp://ftp.ps.pl/dsk0/Fedora/fedora-enchilada/linux/development/ppc64/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Everything/ppc64/os/
[DIR]  ftp://ftp.dntis.ro/pub/.1/ftp.apache.org/perl/mod_perl-2.0.4/docs/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Fedora/ppc/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Fedora/x86_64/os/
[DIR]  ftp://ftp.uni-oldenburg.de/linux/ftp.fedoraproject.org/releases/9/Fedora/i386/os/
[DIR]  ftp://ftp.pbone.net/vol2/download.fedora.redhat.com/pub/fedora/linux/development/i386/os/
[DIR]  ftp://208.209.50.19/pub/.vol02/NetBSD/NetBSD-release-3-1/src/x11/Xserver/os/
[DIR]  ftp://ftp.estpak.ee/pub/NetBSD/NetBSD-release-3-1/src/x11/Xserver/os/
[DIR]  ftp://ftp5.freebsd.org/pub/NetBSD/NetBSD-release-3-1/src/x11/Xserver/os/
[DIR]  ftp://208.209.50.19/pub/.vol02/NetBSD/NetBSD-release-3-1/src/gnu/dist/sendmail/include/sm/os/