Pro-DOS could be thought of as a Disk Operating System (DOS), However, it is more than this, it is a full Operating System that Provides compatibility with CP/M 2.2.

In simple terms this means that a whole world of software that was designed to run under CP/M 2.2. will now run on the SAM Coupé. Pro-DOS uses the same Disk format as the Amstrad PCW 8256 and, as a result, it can read disks from this machine direct, this also Means that there is a vast range of software already available from sources such as Public Domain libraries.

When buying software from a public domain library you must check that it was designed to run under CP/M 2.2 or one of the lower versions, 1.4 for example. Some software will only run under the later versions of CP/M, commonly known as CP/M 3 or CP/M Plus. However, the majority of available software is 2.2 compatible and you should have no trouble running it under Pro-DOS. Some software may need "installing" for the particular machine you intent to run it on, this normally involves terminal (or screen) configuration and sometimes disk data information, most Software includes full configuration instructions and it is usually a simple task.

Pro-DOS runs totally independent of the SAM ROM and DOS and, as a Result , makes no ROM or SAMDOS calls. Therefore, Pro-DOS will Run on any SAM with any version of SAM or Master DOS. Indeed, to Boot Pro-DOS from its boot disk you do not need to have Pre-loaded SAM or Master DOS at all. Pro-DOS automatically adjusts itself to your particular machine, be it a 256K single drive, or a 512K twin drive system, system ensures that it makes the best use of the RAM and drives available.