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The PDP-11 Freeware
FAQ

This is a list of usefull PDP-11 freeware sources that I've compiled over the past few decades. Each entry has the URL of the source, the (as best as I could determine) maintainer of that site, and some of my own comments about the contents of that site.

If you have any comments, corrections, or additions, don't hesitate to contact me via e-mail at shoppa@trailing-edge.com

The most current text version of this list will be available via anonymous ftp from sunsite.unc.edu as the file pdp-11.ftp in the directory /pub/academic/computer-science/history/pdp-11. An HTML version is available at

Shameless plug: I'm looking for pdp-11 users who would be willing to make part of their public domain software collection (DECUS tapes, etc.) available via ftp. I can transfer data from many media (8mm or 9-track magtape preferred, but I can also handle TU58's, TK50's, RX0n's, RX50's, RK05's, RA60's, and RL0n's) and several pdp-11 OS formats (RSX-11, RSX-11 BRU, RT-11, VMS) to the collection at sunsite.

A word about file formats: many ftp sites only know about files as streams of bytes (e.g. Unix-based OS's) and cannot properly handle the wide variety of more complex files available under, for example, RSX-11. Dealing with this problem in a reasonable way is a formidable task. One suggestion is to store sets of files as TPC images of BRU tapes, but this method has the disadvantage of making the files inaccesible to those without a working BRU and a tape drive (of course, those with a VAX running VMS and using the DECUS program BRUREAD can take a plain TPC image as input without having to use an actual tape drive). Another suggestion is to use the RSX-11 librarian's .ULB format to store files along with their special attributes. Recently I've come across a very large collection of RSX DECUS tapes and I'm open to suggestions as to how others would prefer to have me make these available via ftp.

To make things even more confusing, even the way that the simple file structure of RT-11 is handled differs from site to site. In particular, the "newline" convention in RT-11 text files is different than the Unix convention. Different sites have tackled this problem in different ways. At ftp.update.uu.se, for example, RT-11 text files have been translated into the Unix newline convention. This means that text files from this site must be ftp'ed and/or Kermit'ed onto your RT-11 system in text (or ASCII) mode, while all other files must be done in binary (or Image) mode. RT-11 files at other sites, such as sunsite.unc.edu, are stored as exact images of the RT-11 files. These files should be always transferred in binary (or Image) mode at every step.

Site: http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/

Site: ftp://ftp.update.uu.se/pub/pdp11/

Site: ftp://ftp.dbit.com/pub/pdp11/

Site: ftp://shop-pdp.kent.edu/

Site: ftp://ftp.village.org/

Site: ftp://ftp.spc.edu/

Site: The PDP-11 Unix preservation society


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