Add Support for the Nibble (NDO/NIB) Disk Image Format

[trudnai]

File Extension (NDO/*.NIB) - This image is 232960 bytes in size, and it usually has the *.NIB extension. According to the original "Apple2 Emulation Frequently Asked Questions" guide, "every three bytes of data have been 'bit twiddled' into four bytes, and each sector has an 'address field' that has the track and sector numbers." The format was originally used solely in the "ApplEmu" emulator before becoming widely used to store copy-protected software. The conversion utilities listed below are solely for use with "ApplEmu" images containing standard software! NDO images rely on the extra space to store non-standard track information which would otherwise be lost in a DO or PO image. With newer emulators such as AppleWin and ApplePC, NDO can be used to store copy-protected or non- standard Apple disk-images (created by SST - see "Super Saltines Transcopy" in Section 5.3).
On the MACINTOSH - There is currently no way to convert either from or to NDO on the Macintosh. NDO images are used by the "Catakig" emulator (File Creator: 'Ctkg', File Type: 'A2D5')
On the PC - To convert PO disk-images to NDO (for use with ApplEmu), use "Em2Emu" by Tom Baker tombaker@world.std.com. To convert NDO back to DO use "Emu2Em" by Dan Scholnik dpscholn@mtu.edu to re-order this format back into the "standard" 143360 size. AppleEmu can run NDO images containing copy-protected software without conversion. Newer emulators support multiple disk-images types but will support all NDO types containing standard software.
PROGRAM LOCATIONS:
ftp://ftp.apple.asimov.net/pub/apple_II/utility/em2emu.zip
ftp://ftp.apple.asimov.net/pub/apple_II/utility/emu2em.zip