DPUSER.001  by Phil Wheeler [71266,125]
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Disk Power 100 is about the cleverest and most full-featured of
the operating systems supporting the TDD.  Because of the way it
is implemented, it has some advantages over the others; but some
unique compatibility problems also result.

The following are some of my observations after a few days of
DP100 experience.  My biggest negative reactions are: 1) The
loading process is not quick and easy (assumes you won't do it too
often); and 2) You cannot remove it gracefully (needs a
cold-start; see below).  This should not be an issue under normal
usage, since it is intended to be kept in the computer
permanently; but I like to "fiddle", so it is a nuisance to me.

A. How DP-100 is Loaded

These are guesses on my part.  I suspect that only Hugo Ferreyra
knows for sure!

1. Apparently LOADER.BA puts a machine language program in the
   very lowest part of RAM (32768d = 8000h as the starting
   address).  I surmise this based on the fact that SOMETHING
   stays resident while MAXRAM=HIMEM=62960 (it seems) -- and from
   the discussion in the manual (and the DPTIP files) of when CAS:
   and FLOPPY will work and when they will not.

2. FLOPPY.CO will always put it there, whatever else is loaded at
   the time.  Cassette and other OS's (DSKPWR, POWR-DISK, TS-DOS)
   will not put it there unless there are no *Basic* programs on
   the menu.  Note that UR-2 when on the menu acts like a Basic
   program in this regard.

3. This implies that only Basic files (and UR-2) need be removed
   prior to booting with CAS:, TS-DOS or DSKPWR.  It also suggests
   that using FLOPPY after loading DP100 will push the resident
   portion of DP100 out of its (necessary!) low RAM location.

4. If my conclusions re the location of the resident portion of
   DP100 are correct, it is ABSOLUTELY incompatible with the MENU
   utility of the PG Designs RAM expansions, and maybe with SUPERA
   -- as they now stand.  That is because these programs need to
   grab the same fixed location in low RAM.

B. Cautionary Notes

1. Don't ever kill DP100.SY.  You will probably need a cold start
   to set things right.  The only safe method IS a cold start.  It
   turns out that it can be killed, using some of the utilities
   with menu-type Kill functions.  That is unfortunate, because
   it's all too easy to do (fickle fingers, and all of that).

2. If you have the urge to save DP100.SY to a disk, don't bother.
   It messes up the directory and serves no useful purpose, unless
   you get your kicks from formatting disks!

3. Once you have installed DP100, do not use FLOPPY!  See above
   notes.  You may be able to use other stuff such as DSKPWR, but
   if you are committed to Disk Power 100, why bother?

   Actually, this is a bit unfortunate, because DP100 has no
   Backup function.  When using DSKPWR, I usually load FLOPPY for
   formatting and Backup.  I guess you can do a back-up with DP100
   by mass saves and loads, but that is not too convenient.

   There is a bright side.  I think, with DP100, you safely can
   use a version of FLOPPY which has been modified for use with
   the PG Designs MENU.BA utility  (see DL5; TDDTIP.00#).  This
   would allow backups with DP100 installed.  If anyone tries
   this, let us know the result!

4. Do not use the DP100 resident functions to save files from
   within Ultimate ROM II.  I had one bad experience the only time
   I tried it while editing within T-WORD.  This may be unique to
   UR-2, or may be true for Super ROM as well.