Software which has been put into the "public domain" is free for anyone to use. The author often retains copyright and may dictate how the software is distributed; it is usually not to be used for personal gain in commercial programs and there is usually the stipulation that certain files must always be included in any distribution. It is often the case that the source code is supplied and the original author even exhorts other programmers to improve it. In many cases this leads to many versions of the same program by several authors, maybe with similar file names, but general good practice is for program improvers to acknowledge their sources.
A general condition is that the software
cannot be sold but that a reasonable charge may be made for distribution. The
equivalent in PC terms is "freeware". Manuals explaining how to use the software
are usually contained in text files on the disc. In many cases files are compressed
to cram more on to the disc but utilities to expand the files will be found
on the disc.
Public domain software is very mixed; some does very little and may even be
flawed to the stage where it crashes your machine, but at the other end of the
spectrum, some is very good indeed. Word processors, databases and spreadsheets
are best sellers and thus attract the attention of commercial programmers, but
there are still a fair sprinkling of these programs in the public domain although
maybe not as powerful as commercial programs. Many of the best PD programs are
utilities, maybe because these aren't so widely used and are not money-spinners.
Some of my favourite public domain programs are:-
There are loads of other useful public domain files, these are just a few favourites which have solved many problems for me.
Using Public Domain CP/M Software
When faced with a disc with no written manual the first job is to assess the contents. The directory can be shown by using DIR but more information can be obtained about file sizes by using the [ALL] switch, ie DIR[ALL].
However, I use NSWP.COM instead of DIR.COM as in one program this enables ASCII text files to be read and printed out, even if compressed. It will try to read any file and even if the file isn't text this exercise, together with the file extent(type), often gives an indication of the type of file. Locoscript files, for example, can be identified by their characteristic form
Typical ASCII text file extents are
.DOC, .TXT
Typical Locoscript extents are .LOC, .L2, L3
The executable file extent is .COM Various file extent are .BAS (BASIC) .FOR
(FORTRAN) .C or .CC (C language) .COB (COBOL) etc. Various source file extents
are .ASM, .OBJ Batch files have the extent .SUB to be used with SUBMIT.COM
There are many other file extents, you have to use a bit of imagination sometimes
to categorize them.
Public domain discs are very often stuffed to overflowing with files including squeezed or compressed files. Any extent with a Q is likely to be a squeezed file. for example .DQC is probably a squeezed .DOC file. These can be unsqueezed with USQ.COM or other utilities and can be read or printed out from NSWP without unsqueezing first.
Having read all the files which can be read you will probably know something about what's on the disc and can begin to try out the .COM files by typing in the first part. eg for a file DISC.COM, try typing DISC at the prompt then press [RETURN] A .COM file may call another .COM file so you need to experiment here. Once you get a result there may be a menu or on-screen instructions. File sizes can sometimes give clues. Many early Public Domain programs were written for use only by the author or by a closed group so that operating instructions may be sparse, but later programs are quite well documented. Anyway, a lot of the fun in these programs is sussing out how they work and indeed what they do.!
Even more difficult to use are commercial discs which are without their manuals because there is likely to be no on-disc instructions either. The only thing to do is to experiment. If it's a game, look out for groups of keys to move characters, fire weapons etc., such as the arrow keys, [ALT] and [EXTRA], [{Q},{W},{A} and {S}] etc. If all else fails, try pressing keys at random until you get a result; it can be done with a little patience and you may find that you have a really good program. If you have a 7 to 10 year-old available, ask them to try; this age group seems to have special powers over computers.
One thing is absolutely certain; you can't damage your machine by simply trying out unknown software. There are no viruses in CP/M and the worst thing that can happen is that your machine may lock up, needing to be rebooted. If you haven't tried Public Domain software before, give it a try. You can learn a lot and have a thoroughly enjoyable (or frustrating) time.
Ron King
Andover, England
Email.......ron@king27.freeserve.co.uk