PWRTIP.001
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joel dinda
[75725,1134]


For the benefit of the uninitiated, a quick description of Powr-DOS and some
suggestion of why someone might want to acquire it.  Then a few notes you
might find useful.

While POWR-DOS is new to the data library, it had a prior life as a commercial
offering.  Since several of us have acquired experience with the program,
there is a sizable collection of files and programs in DL9.  Except as noted,
all files mentioned in these comments can be found in that DL.

WHAT IS POWR-DOS?
Powr-DOS is an operating system for the Model 100/Tandy 102 and Tandy's
portable disk drive (TDD).  While P-DOS was written for the original TDD, and
has features which only work with that drive, it works quite well with TDD2
(the newer, 200K, version of the drive).

Most of P-DOS's features can be considered extensions of M100 BASIC; in
essence, it permits you to use the drive to expand your computer's memory.
Contrast:  Tandy's FLOPPY is a file transfer program; P-DOS permits BASIC
programs to access disk files much like they access RAM files.  The principal
advantage is that this permits you to manipulate larger files.  This advantage
is subject to some limitations; the most severe is that only one disk file can
be opened at any time.

Powr-DOS permits you to LOAD and SAVE text files directly to and from the TEXT
editor.

The program is self-relocating; it resides in low memory but avoids conflicts
with other LOMEM programs.  I've been using it with PG Designs' 0MENU for well
over a year without difficulty.

WHO SHOULD DOWNLOAD POWR-DOS?
I recommend this program (utility?) highly.  SIG members who own a Model 100
or Tandy 102 and either variety of the Tandy Portable Disk Drive may find it
beneficial.  It offers what might be called the "standard features" of a TDD
DOS, plus a few of its own.  This is an extremely powerful piece of software;
unfortunately, there're not many applications available which take advantage
of the power.  At the price, this product's pretty difficult to fault.

You do *not* need this program if you already own another DOS for the TDD2.

You do *not* need Powr-DOS if you only wish to use your TDD for file
transfers, as DSKMGR is preferable for these operations.

You probably don't need Powr-DOS if you own a TDD1 and any other DOS.  But
read on before deciding.

ASSORTED NOTES
If you want more information, my reviews POWR-D.REV [Powr-Disk] and P-DOS.REV
[Powr-DOS] in DL13 cover a lot of territory.  (Beware: P-DOS.REV is *long*.)

DL9 contains many files relating to this operating system.  See TDDTEK.CAT for
informational files, TDDUTL.CAT for utility programs, and TDDPGM.CAT for
applications.  See further discussion, below, for some suggestions & warnings.

P-DOS was written for use with the original Tandy Portable Disk Drive.  With
TDD1, this is an *extremely* powerful system.  The basis of this claim is the
DSKO$ command, which permits direct sector access from BASIC (thus bypassing
all file structures imposed by M100 & TDD).  One program which takes advantage
of this capability is RECOVR.PWR, one of the files newly available here.

Used with TDD2, Powr-DOS can be thought of as an improved version of
Powr-DISK.

While the direct sector access features don't work with the 200K drive, this
is a full-featured operating system.  Those features [DSKO$ and two associated
MAXRAM+ CALLs] should be avoided, as they will cause your system to hang.

[Note that FLOPPY for the TDD2 offers the same sort of sector access, if you
need it; study TD2TIP.005, RECOV2.TD2, & Tandy's BACKUP.BA if you need clues.]

DSKI$ (a free-space check) *does* work with TDD2.

The most important TDD2 limitation:  40 FILE LIMIT.  While Powr-DOS lets you
access the disk's entire 200K, the second directory (Bank 1) is unavailable to
you without what amounts to heroic efforts.  This means you need to fill the
disk while using only 40 file names (not usually a problem for me) or resign
yourself to less than optimal use of the drive.  (You *could* use FLOPPY to
access Bank 1 if it proved necessary.)  There's a "fix" for this problem in
FLIP.T2, but I'm not convinced the effort is worth the trouble.  You may feel
free to disagree.


Some comments on files:  I haven't checked every program out, so I've likely
missed things....

Most programs written for *any* M100/etc operating system will work with this
one.  Fortunately, all the DOS programmers implemented obvious extensions to
BASIC, so file access is pretty consistent from DOS to DOS.  The programs to
avoid are hardware-specific utility programs (and, if using a TDD2, Powr-DOS
programs which use DSKO$ to shortcut disk reads).

The following programs will *NOT* work on the TDD2, regardless of operating
system:  COPYFL.PDS and RENAME.PDS (both of these are mine) and Acroatix'
RECOVR.PWR and D-TEXT.PWR.  These use DSKO$, and will quickly hang things up.

The following program will *NOT* work with Powr-DOS:  Woods Martin's PDMENU.
This program uses program CALLs which only exist in Acroatix' Powr-DISK.

Converting your favorite programs to use Powr-DOS's capabilities is generally
a matter of appending 0: before the file name.  Care must be taken to avoid
attempting to open two disk files simultaneously (forbidden by the hardware,
except to tricky programmers).  I've often found it useful to put "Searching"
(or whatever) on the display because file manipulations are considerably
slower.


BOTTOM LINE:  Highly Recommended
Any user with M100/T102 & either Tandy Portable Drive should find P-DOS's
extensions to BASIC useful.  For the original TDD, this is an exceptionally
powerful program (utility); so powerful, in fact, that most users will simply
ignore some of the features.  In TDD2, it's a somewhat more powerful version
of Acroatix's Powr-Disk, which is plenty powerful for most users.

Users who *only* want to transfer files will probably prefer something else,
and users with access to another TDD operating system probably don't also need
this one.  Everyone else should pick it up.

joel
15jun88