AIPS HELP file for QCREATE in 31DEC19
As of Tue Dec 18 4:02:34 2018
Type: Adverb (Real)
Use: Controls how files > 1 Mbyte are created. If <= 0, the files
are created on disk by filling the entire requested space with
zeros. This guarantees that the disk space is reserved and
initialized but can take a long time for files of many Gbytes.
If > 0, files are created by writing a buffer or 2 of zeros at
the requested end of file so that the file will appear to be as
big as desired. However, the parts not filled with zeros are
not reserved and might not be available when the task gets
around to writing them. It also trusts all AIPS programs to
not assume that the disk is zero to begin with. The up side of
this method is that it is very fast and, if you have lots of
disk space, the danger of running out is minimal.
This parameter is used on all file creations - effectively it is
an adverb to the pseudo-verb GO.