Tandberg Data
Track, Tape format and Encoding Specification
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Tandberg SLR Reference Manual
6-3
6.2.2. MLR3 (SLR50) Format
The organization of the data is equal to QIC-5010-DC and SLR6 (SLR24), see Section 6.2.1.
The ECC-blocks are, however, computed differently. In MLR3 (SLR50), ECC is computed
across the two, parallel tracks. This improves error correcting capability in the presence of
tape defects. It is important to realize, however, that
data
is not interleaved across tracks
(except for ECC-blocks), but the data used to compute ECC is fetched from different tracks.
Please refer to the MLR3 (SLR50) format specification document for further information.
6.2.3. ALRF-1 and ALRF-6 Formats
The SLR100, SLR75 and SLR60 media supports the ALRF-1 format, while the SLR140
supports ALRF-6. These formats have 24 servo tracks and 192 data tracks. Four tracks are
written in parallel.
All user data is organized in logical frames. A frame has 108 data blocks and 20 ECC blocks.
A frame-set consist of four frames (labeled A, B, C and D ). The frames are divided among
the four simultaneously written tracks on the tape. The blocks for the four frames are
distributed across the four tracks starting from block number 0 in each frame, and writing
increasing block numbers. Each frame has two ECC-interleaves as QIC-5010 – one for odd
and one for even blocks. Each interleave has 54 data blocks and 10 ECC-blocks. On the four
tracks the blocks within an interleave are distributed in a way that keeps blocks from the
same interleave away from each other on each track.
Please refer to the Tandberg ALRF-1 and ALRF-6 format specification documents for further
information.
6.2.4. ALRF-2 Format
The SLR7 media has 18 prewritten reference tracks at BOT and 72 data tracks. Two tracks
are written in parallel.
The user data is organized in the same way as for the ALRF-1 format except that it is written
at 2 tracks instead of 4. This means that data from 4 frames (and 8 ECC interleaves) are
distributed on the two tracks with maximum distance between blocks in the same ECC
interleave.
6.2.5. Other Formats
The QIC-4GB and QIC-2GB formats are described in the corresponding QIC-standard docu-
ments and in the
Tandberg SLR Series (TDC 4000) Reference Manual.