'MB'= MegaBytes: File Segment Size
Description
Controls segment size in multi-segmented files. 'MB' must be set to a value to activate the multi-segmented file feature.
PxPlus uses the value set in the 'MB' parameter as a target size for each segment. If, for example, you wanted all files to be around 1 GB, you would set the 'MB' parameter to 1024 representing 1024 megabytes or 1 GB.
The actual size of each segment will be determined based on the block size of the file. Internally files are partitioned into logical 'units' where each unit represents a portion of the file whose free space is managed by a single block (an inventory block). The Unit size can be computed as follows:
Unit size = ((bksz - 6) * bksz)
The value bksz above represents the block size of the file -- normally between 1 and 8 kilobytes. You can use the BSZ= option when you create the file to override the default block size for a file.
As a unit is filled, the system will check to see if the file exceeds the 'MB' setting. If so, the next unit of the file will be placed in a new segment.
The following table lists the maximum number of segments allowed for a file based on valid block sizes (1 to 31 kilobytes):
Block Size | Unit Size | Segments | Block Size | Unit Size | Segments | Block Size | Unit Size | Segments |
31K | 961MB | 124 | 30K | 901MB | 120 | 29K | 841MB | 116 |
28K | 784MB | 112 | 27K | 730MB | 108 | 26K | 676MB | 104 |
25K | 625MB | 100 | 24K | 577MB | 96 | 23K | 529MB | 92 |
22K | 484MB | 88 | 21K | 442MB | 84 | 20K | 400MB | 80 |
19K | 361MB | 76 | 18K | 325MB | 72 | 17K | 289MB | 68 |
16K | 256MB | 64 | 15K | 226MB | 60 | 14K | 196MB | 56 |
13K | 169MB | 52 | 12K | 144MB | 48 | 11K | 121MB | 44 |
10K | 100MB | 40 | 9K | 81MB | 36 | 8K | 64MB | 32 |
7K | 49MB | 28 | 6K | 36MB | 24 | 5K | 25MB | 20 |
4K | 16MB | 16 | 3K | 9MB | 12 | 2K | 4MB | 8 |
1K | 1MB | 4 |
Default
'MB'=0