Exabyte EXB-8505 8mm - Manual (Page 45)

Physical Blocks
For all three physical track formats, each physical track contains eight
physical blocks. A physical block can contain user data or other
information. As shown in Figure 2-8, a physical block containing user
data includes the following information:
2 bytes of cyclic redundancy check (CRC) data
400 bytes of error correction code (ECC) data
1,024 bytes of uncompressed user data or 2,048 of compressed
user data (assuming a 2:1 compression efficiency)
14 bytes of header information
Note: The physical block header, ECC data, and physical block CRC
data do not affect the data capacity of the tape.
Figure 2-8 Physical block format for all logical formats (8200c or 8500/8500c physical track structure shown)
May 1994 EXB-8205 and EXB-8505 2-9
(Standard and XL)
2 Recording Format