Long Filename Systems

Legacy Long Filename Systems
Prior to RISC OS 4, FileCore-based filing systems (eg ADFS, SCSIFS, RAMFS, IDEFS) were limited to 77 items per directory and 10 character filenames. A number of workarounds were developed to overcome this restriction. Each of the programs LongFiles, raFS and X-Files took a different route to solving the problem. All three programs were designed to minimise the risk of actually losing files, although problems with any of them may cause the long file names to be lost.

LongFiles [[Image:longfiles34x34.png|LongFiles icon]]
LongFiles is a module which creates a 'hidden file' within each directory to store its long filename information. While the LongFiles module is active, this file remains hidden, and all the other files are displayed with long names. If LongFiles is quit, the hidden file appears and the other files show their abbreviated names. Renaming them at this stage causes the long filename data to be lost. It's important to note that LongFiles only addresses the problem of long filenames, not the ADFS 77-file-per-directory limit. In fact, the hidden file used by LongFiles to store long filename information reduces the number of files available in a directory to 76. However, those files remain accessible even when the LongFiles module is not active; only the long filename information is unavailable. This system is quite similar to the long filename management used in Windows 95, although LongFiles actually predates Win95 by a year or two.

raFS [[Image:rafs43x36.png|raFS icon]]
raFS works differently again; files are stored in a custom directory structure using the underlying file system. This structure is hidden from the user while raFS is running, and gives unlimited files per directory with unlimited-length names. When raFS is not running, the long filenames and long sub-directory names are unavailable, but individual files can be retrieved separately from one another.

X-Files [[Image:Xfiles34x29.png|X-Files icon]]
X-Files uses an image filing system, and file handling is very similar to the management of files within an archive being managed by ArcFS or SparkFS. When X-Files is running, X-File images function as directories with a different icon; inside each X-File, files are stored with long filename information, and with no limit on the number of files that can be stored within a single directory. When X-Files is not running, an X-File image file is a monolithic object and individual files within the image cannot be accessed or manipulated.

As a precaution against file corruption, a separate utility called X-Recover is provided. This tool can be used to retrieve files from a corrupt X-File.