A file accessing scheme allows logical files to be processed outside of the native
operating system and its logical I/O subsystem. When an application program wants
to process a file outside of the native operating system, a file information block
is built with a special type of file designated as "virtual." A pointer is provided
within the file information block to a handler. The handler is a library that is
external to the native operating system. The library processes the file without
using the native operating system. Upon completion of the processing, the handler
returns the operation results to the file information block and control is transferred
back to the application program.
