Twin directories of dos:

[DIR]  ftp://ftp.parc.xerox.com/pub/lfg/previous/dos/
[DIR]  ftp://ftp.parc.xerox.com/pub/music/digital_tradition/tune_software/dos/
[DIR]  ftp://ftp.parc.xerox.com/pub/pueblo/vista/dos/
[DIR]  ftp://ftp.ox.ac.uk/pub/crypto/pgp/OLD/pc/dos/
[DIR]  ftp://ftp.uni-leipzig.de/pub/pc/dos/
[DIR]  ftp://ftp.qms.com/pub/cta/out_going/dos/
[DIR]  ftp://ftp.qms.com/pub/cts/out_going/dos/
[DIR]  ftp://ftp.qms.com/pub/crc/out_going/dos/
[DIR]  ftp://ftp.qms.com/pub/drivers/dos/
[DIR]  ftp://ftp.mimuw.edu.pl/People/jsbien/pto/dos/
[DIR]  ftp://ftp.mimuw.edu.pl/People/jsbien/dos/
[DIR]  ftp://ftp.udel.edu/pub/people/baxter/skey/dos/
[DIR]  ftp://ftp.research.telcordia.com/pub/nmh/dos/
[DIR]  ftp://ftp.dit.upm.es/mirrors/ftp.ox.ac.uk/pub/crypto/pgp/OLD/pc/dos/
[DIR]  ftp://ftp.csufresno.edu/dept/physics/PIRA/dos/
[DIR]  ftp://ftp.mathematik.tu-darmstadt.de/pub/department/software/conceptanalysis/dos/
[DIR]  ftp://ftp.unice.fr/dos/
[DIR]  ftp://ftp.eenet.ee/pub/cpan/doc/FAQs/dos/
[DIR]  ftp://ftp.eutelia.it/pub2/CPAN_Mirror/doc/FAQs/dos/
[DIR]  ftp://ftp.eutelia.it/pub/Sunsite_Mirror/utils/dos/
[DIR]  ftp://ftp.stat.umn.edu/pub/macanova/OLD/dos/
[DIR]  ftp://ftp.stat.umn.edu/pub/macanova/userfun/dos/
[DIR]  ftp://ftp.stat.umn.edu/pub/macanova/dos/
[DIR]  ftp://ftp.stat.umn.edu/pub/macanova.old/OLD/dos/
[DIR]  ftp://ftp.stat.umn.edu/pub/macanova.old/dos/
[DIR]  ftp://ftp.mines.edu/CSM/dos/
[DIR]  ftp://ftp.mines.edu/pub/dos/
[DIR]  ftp://ftp.saintjoe.edu/pub/CPAN/doc/FAQs/dos/
[DIR]  ftp://ftp.wins.uva.nl/pub/ict/dos/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/support/makeprog/dos/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/support/poster/dos/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/nonfree/support/jpeg2ps/dos/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/fonts/utilities/mathkit/dos/
[DIR]  ftp://ftp.inf.utfsm.cl/pub/tex-archive/graphics/mathspic/dos/
[DIR]  ftp://ftp.acs.appstate.edu/pub/pc/dos/
[DIR]  ftp://ftp.psg.com/pub/ip-for-pc/RAINet.kit/dos/
[DIR]  ftp://ftp.unc.edu/pub/empd/products/EDSS/test/public_domain/plplot_old/sys/dos/
[DIR]  ftp://ftp.ipswitch.com/ipswitch/Product_Support/Vantage/dos/
[DIR]  ftp://ftp.ema.fr/pub/pc/dos/
[DIR]  ftp://ftp.kfki.hu/pub/packages/security/COAST/netutils/skey/dos/
[DIR]  ftp://ftp.kfki.hu/pub/packages/security/pgp/OLD/pc/dos/
[DIR]  ftp://ftp.kfki.hu/pub/packages/perl/CPAN/doc/FAQs/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/2009-10-05_0512-0400.AnonymousFTPBackup/pub/ada/gw-adaed/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/2009-10-05_0512-0400.AnonymousFTPBackup/pub/ada/smallada/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/2009-10-12_0512-0400.AnonymousFTPBackup/pub/ada/gw-adaed/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/2009-10-12_0512-0400.AnonymousFTPBackup/pub/ada/smallada/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/NDMP_AUTO_SNAPSHOT574/pub/ada/gw-adaed/dos/
[DIR]  ftp://ftp.seas.gwu.edu/.snapshot/NDMP_AUTO_SNAPSHOT574/pub/ada/smallada/dos/
[DIR]  ftp://ftp.epson.it/pub/fr/pilotes/jetencre/inkjet/dos/
[DIR]  ftp://ftp.epson.it/pub/fr/pilotes/jetencre/dos/