A description of the DLLs used in the Cairo Disk Administrator
==============================================================

There are several EXEs and DLLs integral to the operation of
the Disk Administrator.  This note discusses those executables,
their interrelationship, why they are necessary, and why the
functionality is broken up so.

windisk.exe -- the guts, including partitioning, fault tolerance configuration,
and file system operations (format, chkdsk, label).

A note on the NT file and disk utilities: All the NT file and disk
utilities---chkdsk, format, comp, attrib, etc---heavily utilize C++:
most everything of interest is a class---command-line arguments,
buffers, strings, stacks, disk drives, HPFS & FAT file system information,
etc.  Much common code, including classes for the examples just
given, reside in ulib.dll.

fmifs.dll -- a small utitilty converting between NT utility DLL APIs
and callback functions.  This DLL was originally written for use by File
Manager, for floppy disk formatting and volume label changing.  It
isolates its clients from the vagaries of the utilities library classes,
namely the message feedback class.  All feedback from chkdsk, format, etc,
is normally reported by a Display() method being called on a MESSAGE
class, a pointer to which is passed to the file system Format(),
Chkdsk(), etc. API.  The fmifs.dll code converts this message into a
function callback, passing along any relevant information.  To use the
file system utility APIs directly would force clients to compile in the
utilities environment, incorporating lots of undesirable C++ stuff.

ifsutil.dll -- installable file system utilities.  C++ classes
providing low-level file system and disk abstractions for the
NT installable file system interface.

uofs.dll, untfs.dll, uhpfs.dll, ufat.dll -- the file system
utilities (chkdsk, format, label, etc) for each file system.  Note that
the code incorporated into these DLLs is used in several distinct and
diverse environments.  These are the setup environment, as autochk in
the boot environment, and from the chkdsk, format, label, etc., front
ends.  And now, from Disk Administrator.  Note that these are amazingly
different.  For example, in the boot environment there is no virtual
memory!  Message feedback requirements are obviously different in the
character-based and GUI environments.

ulib.dll -- a library for the utilities.  Includes various common-code
helper classes, as described above.



Here are the dependencies (ignoring ntdll.dll, kernel32.dll, etc):

windisk.exe depends on fmifs.dll

fmifs.dll: depends on ulib.dll, ifsutil.dll

ifsutil.dll: depends on ulib.dll

uofs.dll ufat.dll, untfs.dll, uhpfs.dll: depend on ulib.dll, ifsutil.dll

ulib.dll: no dependencies of note



Here's the *approximate* tree (DAG, actually):  things above depend on
things below.  Same level means no dependencies.


                      windisk.exe

                       fmifs.dll

         ufat.dll uhpfs.dll untfs.dll uofs.dll

                      ifsutil.dll

                       ulib.dll



Note that windisk lazy-loads fmifs.dll: only when an operation requiring
file system operations is to be performed does windisk load this dll.