FAQ - How are file sizes determined on Connect:Direct Tandem when no Extents are set in the SYSOPTS? (SCI52912)
depends on which platform is receiving.
The sending platform provides current
allocation based on the sending file attributes - number of blocks, extents,
block size, etc.
The receiving platform does its best to interpret the size attributes
provided by the sender, then calculates the space required on the local node.
There's a bit of approximation involved, since differing platforms store data
in different ways, with varying amounts of overhead required for the file. A
Windows data set takes up only the space need to store the data (the EOF
value), plus the slack space in the last disk cluster allocated for the file.
The same data stored on the Tandem, in a structured file, could take up to
twice that same amount of space if the "worst case" condition occurs, in which
the logical records are stored one record per block with 49% slack space. For
instance, a 2050 byte LRECL in a 4096 byte block. There's only room for one
logical record in the block, so nearly half the space is
Connect:Direct Tandem, Release 3.1.00