DOSBox emulator is the kind of program, that emulates an IBM PC compatible computer running a DOS operating system.
Many IBM PC compatible graphics and sound cards are also emulated.
This means that original DOS programs (including PC games) are provided with an environment in which they can run correctly, even though the modern computers have dropped support for that old environment.
DOSBox is a command-line program, configured either by a set of command-line arguments or by editing a plain text configuration file.
For ease of use, several graphical front-ends have been developed by the user community.
A popular feature of DOSBox is its ability to capture screenshots and record gameplay footage.
The video is compressed using the lossless Zip Motion Block Video codec.
In its uncompressed state the footage is almost an exact replica of the actual program.
The video recording feature was added in version 0.65. In earlier versions, one had to rely on custom modifications and a third-party screen recorder to record video, but the quality and emulator performance was generally very poor.
The DOSBox project has a policy of not adding features that aren't used by DOS games if they take significant effort to implement, are likely to be a source of bugs or portability problems, and/or impact performance.
Perhaps the most common hardware feature of DOS-era PCs that the official version of DOSBox doesn't emulate is the parallel port that was used to connect printers.
As an alternative, the PrintScreen function of modern OSs can be used to capture the output of DOSBox.
For similar reasons, no support for long filenames and Ctrl-Break is added into official versions, though support for them is available in some unofficial enhanced SVN builds.
How to install via a terminal window:
This will install an older version: 0.74
sudo apt-get install dosbox
Press Enter, done.