ParaDOS

A DOS for 3½" drives, coded by Richard Wilson and initially marketed by Quantum Computing.

ParaDOS was a complete replacement for the standard 16k AMSDOS ROM.

The first 8k was a patched version of the standard AMSDOS code, with the second 8k used for the large-format patch code and a user-friendly disc utility (accessed by the |DRIVE command without any parameters).

Among the functions of the utility were fast file copying and batch erasing.

ParaDOS largely supplanted ROMDOS as AMSDOS replacement.

Unlike ROMDOS, ParaDOS made no check for the presence of an AMSDOS ROM on sign-on.

This enabled it to be used in ROM 7 as a direct replacement for AMSDOS, improving compatibility with programs which unthinkingly initialised ROM 7 alone.

This, however, also cast some doubts on the propriety of its intellectual property stance.

It is likely that ParaDOS would have been questioned more rigorously had it not been introduced towards the end of the CPC's commercial life.

Unlike other expansion ROMs ParaDOS has no checksum in address &FFFF. This fact should be considered when performing f. e. a ROM integrity check or similar. It the usual checksum algorithm is used the checksum is &26.

There is a special version of ParaDOS, it's called VaraDOS and has the great Vortex format enabled by default.