deallocation of old copies, DyBASE flushes all modified pages on disk
to synchronize content of the memory and disk file. After that DyBASE
changes current object index indicator in database
header to switch roles of the object indices. Now object index, which was
current becomes shadow, and shadow index becomes current. Then DyBASE again
flushes modified page (i.e. page with database header) on disk, transferring
database to new consistent state.
After that DyBASE copies all modified handles from new objec