<trclass="memdesc:afb840f56fb39b1074f96715d102e2c0f"><tdclass="mdescLeft"> </td><tdclass="mdescRight">Partition number (unique identifier for this partition). <br/></td></tr>
<trclass="memdesc:af2cdde924cd050523ad0fb453eb5842d"><tdclass="mdescLeft"> </td><tdclass="mdescRight">First block in the partition (inclusive). <br/></td></tr>
<trclass="memdesc:a19aec00f3d7b0850bf49b055dbcc837d"><tdclass="mdescLeft"> </td><tdclass="mdescRight">Last block in the partition (inclusive). <br/></td></tr>
<divclass="textblock"><p>Describes a single physical partition on a tape medium. </p>
<p>Tape partitions are physical divisions of the tape storage area, each with its own block address space. Partitioning allows a single tape to be logically divided for organizational purposes, access control, or compatibility with different systems.</p>
<p><b>Partition Number:</b> The partition number uniquely identifies the partition on the tape. Most tapes have a single partition (partition 0), but advanced formats like LTO, DLT, and AIT support multiple partitions. The numbering scheme is format-specific:</p><ul>
<li>Single-partition tapes: Usually partition 0</li>
<li>Multi-partition tapes: Typically 0-255, though most formats support fewer</li>
</ul>
<p><b>Block Range:</b> Each partition has an independent block address space starting from its FirstBlock. The FirstBlock and LastBlock fields define the inclusive range of blocks in the partition:</p><ul>
<li>FirstBlock: The first block number in this partition (often 0)</li>
<li>LastBlock: The last block number in this partition (inclusive)</li>
</ul>
<p><b>Block Address Spaces:</b> Block addresses are local to each partition. For example:</p><ul>
<p>Block 0 in partition 0 is distinct from block 0 in partition 1. When referencing a block, both the partition number and block number are required for uniqueness.</p>
<p><b>Partition Size:</b> Partition size in blocks = (LastBlock - FirstBlock + 1) Total tape capacity = sum of all partition sizes</p>
<p><b>Physical Organization:</b> On physical tape, partitions are typically laid out sequentially:</p><ul>
<li>Partition 0 occupies the beginning of the tape</li>
<li>Partition 1 follows partition 0</li>
<li>And so on...</li>
</ul>
<p>Some formats allow non-sequential access to partitions via tape directory structures or partition tables stored in a leader area.</p>
<p><b>Use Cases:</b></p><ul>
<li><b>Data segregation</b>: Separate system backups from user data</li>
<li><b>Multi-system use</b>: Different partitions for different operating systems</li>
<li><b>Tiered storage</b>: Fast-access partition for indices, bulk partition for data</li>
<li><b>Compatibility</b>: Legacy system may require specific partition layouts</li>
<li><b>Write protection</b>: Some formats allow per-partition write protection</li>
</ul>
<p><b>Format Examples:</b></p><ul>
<li><b>LTO (Linear Tape-Open)</b>: Supports 2-4 partitions depending on generation</li>
<li><b>DLT (Digital Linear Tape)</b>: Typically 1 partition, some variants support more</li>
<li><b>DAT (Digital Audio Tape)</b>: Usually 1 partition</li>
<li><b>QIC (Quarter-Inch Cartridge)</b>: Typically 1 partition</li>
</ul>
<dlclass="section note"><dt>Note</dt><dd>Partition numbers are format-specific. Some formats use 0-based numbering, others use 1-based. The Aaru format preserves the original numbering.</dd>
<dd>
Not all tape formats support partitioning. Single-partition tapes are common and have one entry with Number=0.</dd>
<dd>
Partitions cannot overlap in the physical block space, though the logical block numbering within each partition may start from 0.</dd>
<dd>
Empty partitions (reserved but unused space) may exist with FirstBlock > LastBlock or with no files allocated to them. </dd></dl>
<pclass="definition">Definition at line <aclass="el"href="tape_8h_source.html#l00319">319</a> of file <aclass="el"href="tape_8h_source.html">tape.h</a>.</p>
<p>Starting block address for this partition's address space. Often 0, but format-dependent. </p>
<pclass="definition">Definition at line <aclass="el"href="tape_8h_source.html#l00323">323</a> of file <aclass="el"href="tape_8h_source.html">tape.h</a>.</p>
<pclass="reference">Referenced by <aclass="el"href="tape_8c_source.html#l00985">aaruf_get_tape_partition()</a>, and <aclass="el"href="tape_8c_source.html#l01199">aaruf_set_tape_partition()</a>.</p>
<p>Ending block address for this partition's address space. Must be ≥ FirstBlock. The partition contains all blocks from FirstBlock through LastBlock inclusive. </p>
<pclass="definition">Definition at line <aclass="el"href="tape_8h_source.html#l00325">325</a> of file <aclass="el"href="tape_8h_source.html">tape.h</a>.</p>
<pclass="reference">Referenced by <aclass="el"href="tape_8c_source.html#l00985">aaruf_get_tape_partition()</a>, and <aclass="el"href="tape_8c_source.html#l01199">aaruf_set_tape_partition()</a>.</p>
<p>Partition number (unique identifier for this partition). </p>
<p>Identifies this partition among all partitions on the tape. Valid range: 0-255, though most tapes use 0-3. </p>
<pclass="definition">Definition at line <aclass="el"href="tape_8h_source.html#l00321">321</a> of file <aclass="el"href="tape_8h_source.html">tape.h</a>.</p>
<pclass="reference">Referenced by <aclass="el"href="tape_8c_source.html#l01199">aaruf_set_tape_partition()</a>, and <aclass="el"href="tape_8c_source.html#l00347">process_tape_partitions_block()</a>.</p>
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