Advanced Disc Filing System

The Advanced Disc Filing System (ADFS) is a computing <a href="/facts/File_system/FdPm90uc">file system</a> unique to the <a href="/facts/Acorn_Computers_Ltd/jCddUElC">Acorn</a> computer range and <a href="/facts/RISC_OS/Pc96teso">RISC OS</a>-based successors. Initially based on the rare Acorn Winchester Filing System, it was renamed to the Advanced Disc Filing System when support for <a href="/facts/Floppy_disc/rShxfuxa">floppy discs</a> was added (using a <a href="/facts/Western_Digital_FD1771/hYaXGWQR">WD1770 floppy disc controller</a>) and on later <a href="/facts/32-bit/TDMVce8s">32-bit</a> systems a variant of a PC-style floppy controller.
Acorn's original <a href="/facts/Disc_Filing_System/SMcUvHxG">Disc Filing System</a> was limited to 31 files per disk surface, 7 characters per file name and a single character for directory names, a format inherited from the earlier Atom and System 3–5 <a href="/facts/Eurocard_(printed_circuit_board)/ceeDsokd">Eurocard</a> computers. To overcome some of these restrictions Acorn developed ADFS. The most dramatic change was the introduction of a hierarchical directory structure. The filename length increased from 7 to 10 letters and the number of files in a directory expanded to 47. It retained some superficial attributes from DFS; the directory separator continued to be a dot and $ now indicated the hierarchical root of the filesystem. ^ was used to refer to the parent directory, @ the current directory, and \ was the previously visited directory.
The BBC Master Compact contained ADFS version 2.0, which provided the addition of format, verify and backup commands in ROM, but omitted support for hard discs.

Advanced Disc Filing System open-in-new

Advanced Disc Filing System