YaPaDOS is patch for [[AMSDOS]] and [[ParaDOS]] that allows to redirect disk access to harddisk. This is done with keeping highest possible compatibility, so only 20 bytes of RAM are used (including 6 used by PARADOSParaDOS).
Instead of reading and writting floppy, a continous and limited area on harddisk is used, that has the same amount of sectors, as the floppy. The area is called diskimage. Each drive separately A: and B: can be directed to floppy or one of diskimages. You can change the diskimages as you would change the floppies, but by opening some special files.
The IDEDOS partition contain diskimages, that can have various size (e.g. 180kB, 800kB, 5MB). Up to 999 diskimages can be created and accessed.
Diskimages are selected by their numbers 1..999 (0 means floppy). Only the number after dot matters. Names of diskimages can be listed from a virtual device called superdisk. Superdisk is read-only. After the superdisk is selected, the diskimage then can be selected without the '''^ ''' sign in file name.
The '''^ ''' sign placed as first in file name used in open file function tells the operating system to do something special:
'''LOAD"^" ''' - selects superdiskLOAD"^xxxxxxx.nnn" - selects diskimage number nnnLOAD"^.0" - selects floppy
'''LOAD"^DESTROYxxxxxxx.MBRnnn" ''' - clears MS-DOS partition tableLOAD"^DBnnnnn.mmm" - creates IDEDOS partition of nnnnn cylinders and up to mmm diskimagesLOAD"^MAKENEW" - adds selects diskimage respectively to current XDPBLOAD"^MAKENEW.nnn" - as above, but enlarage to number nnn kilobytes for safety
'''LOAD"^.0"''' - selects floppy
'''LOAD"^DESTROY.MBR"''' - clears MS-DOS partition table (also needs some POKEs for safety) '''LOAD"^DBnnnnn.mmm"''' - creates IDEDOS partition of nnnnn cylinders and up to mmm diskimages (needs some POKEs to set CHS geometry) '''LOAD"^MAKENEW"''' - adds diskimage respectively to current XDPB '''LOAD"^MAKENEW.nnn"''' - as above, but enlarage to nnn kilobytes for safety The '''^ ''' sign allows to change diskimages in every old software that enables opening any file and not crashes, when the file is empty. No changes in such software are needed to select diskimage on harddisk or redirect the drive to floppy.