PDP-8 Archive File Formats

RX01 and RX02 floppy images

These are the sector contents of all tracks in logical sector order. RX01 are 77 tracks and 26 128 byte sectors per track. RX02 uses same format except 256 byte sectors. Drives are single sided.

RK05 hard disk images

These are the sector contents of all tracks in logical sector order. Media has 203 cylinders, two sides, and 16 256 byte sectors per track.

TU56 DECtape images

These are 12 bit words stored in 16 bit field. 129 words are stored for each block. Number of blocks is normally 1474.

LINCtape images

These are 12 bit words stored in 16 bit field. The tape image has this structure appended after the data blocks.

   struct {
      unsigned short block_size;
      short first_block;
      short first_rev_block;
   } linc_info;

Block_size is the block size in 12 bit words. first_block is the number of the first block in the image. first_rev_block is the block number of the last block on the tape (block number from the reverse block number field). LINKtapes frequently have negatve block numbers at the beginning. If first_block is negative skip -first_block to find block zero in the image.

For all images the order starts with cylinder 0 side 0 sector 0. All sectors for side, then next side, then next cylinder. All data is stored little endian.

Feel free to contact me, David Gesswein djg@pdp8online.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with. I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation.

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