Resource Manager Routines
The first group of routines described here deals with modified routines for
opening or creating resource files. These routines are compatible with new file
specification conventions for System 7.0 and the Hierarchical File System
(HFS). System 7.0 introduces a simple, standard format for identifying a file
or directory, the file system specification (FSSpec) record. partial resources. If you are working with a very large resource, you can alter
a part of the resource instead of having to read it into memory, which may be
im possible. You can also change the size of a resource on disk. Note that if you
increase the size of the resource, the new portion of the resource will be
un initialized, and if you decrease the size, you may lose valuable data
in the resource.