Over the last years I've used a set of unique tools which names have faded into history but when mentioned still bring a warm feeling to people who have used these tools. These tools were on often on platforms which didn't stand the test of time, for good or bad reasons.
4DOS and 4OS2 by JP Software.
Everybody who has ever tried to write a batch script in the MS-DOS COMMAND.COM interpreter knows about its limitations. The 4DOS interpreter took these limitations away and replaced them with powerful features. Interactive batch files suddenly became possible, filename completion was introduced, coloured directory overviews and string manipulation became a piece of cake.
As long as MS-DOS was sold, 4DOS would live on. But the moment the command-line was replaced by the GUI of MS-Windows95, it was dead. Obsoleted because the operating system didn't run from the command-line interpreter anymore.
Qedit by SemWare.
By default, MS-DOS came with a editor called "edlin" which was enough to do some rough editing to get a system working again, but for the rest it was not worth mentioning.
Qedit on the other hand, it was full screen, it was fast, it had split window support, it had ASCII drawing support, it could change the resolution of the monitor to 43 or 50 lines and it could edit files hundreds of kilobytes big.
On the MS-DOS platform it was the best text editor you could get, but as so many other applications it didn't survive the migration to the GUI of MS-Windows: It had a more-or-less working text editor and the editors coming with software development suites had full blown IDEs.
ModPlay Pro by Mark J Cox.
Before the rise of the compressed music (read: MP3), the Amiga world developed a way to store music efficient: Instead of a stream of sound, it recorded samples and the patterns to play the samples in. Since the musical part of a song (so not the voice) consist of repeating elements, it was space-wise very cheap to store the song. And that is the MOD file format.
ModPlay Pro was text-based and had several views of the data being used. One was a frequency/volume overview and one was a tracker overview, in which you could exactly see the pattern being followed and the samples being played. And if you followed it often and intensive enough you started to involuntary "disassemble" songs you heard on the radio into the four tracks available in the MOD format.
The MOD format became popular before soundcards were widely available and affordable. The workaround for it was to build a simple D/A convertor on the parallel port of the computer with a cable to your stereo. And if you bought a second parallel port you could even have it in stereo!
With the rise of more powerful computers and faster networks the MOD format became unpopular in favour of the MP3 format.
TheDraw by TheSoft Programming Services.
TheDraw was the tool of ANSI BBS Administrators and wannabees to create fancy menus and of ANSI artist to create text based animations.
Creating a coloured line with ANSI codes isn't difficult, just cumbersome. To change a colour of the next character you need four characters of which one isn't printable ("ESCAPE [ 25 m"). Testing the menu out can be done from the command-line but figuring out where a colour change is necessary is next to impossible.
Not with TheDraw. With TheDraw you could design the ANSI menu as-is and then write the whole sequence of ANSI escape codes and strings to a file, ready to be displayed on your BBS.
Where did it go? With the rise of the WWW and the demise of the BBS, ANSI became an obsolete in favour of HTML and images.
DESQview by Quarterdeck
You have your Qedit editor, your Turbo C compiler and your ModPlay Pro, but you can not run them all at the same time. After all, this is all still the MS-DOS era! Luckely Quaterdeck developed a lightweigth text-based pre-emptive task switcher called DESQview. That way you could run multiple MS-DOS programs at the same time, without having to quit them or to suspend them. So you could edit your program, compile it in the next task and test it in a third task.
We all know what happened to the MS-DOS market, and DESQview is one of its victims...