PSWDM.100 is a BASIC file which creates, when run, a machile language log-
on program (PW.CO).  The resulting code occupies 250 bytes at the top of user 
memory (62710d to 62959d) and provides full protection for your files when 
properly used.  Using machine code instead of BASIC averts the possibility of 
aborting the program by quick stabs at the break key before it's disabled, by 
overflowing string storage with lengthy input, or by re-enabling the break key
with a screen dump, which are problems with most BASIC programs.
    To load the program, download PSWDM.100 to your Model 100, verify the 
checksum (see DWNCHK.WM3 in this DL), load the file into BASIC, and RUN.  The 
program will prompt you for an ID code (3-10 characters), then will load and 
save PW.CO.  Any printable Model 100 characters can be used for your ID, not 
just standard ASCII alphanumerics.
******* !!! WRITE DOWN YOUR ID CODE AND PUT IT UNDER YOUR MATTRESS !!! *******

So far as I'm aware, the only way to access the computer without it while 
PW.CO is running is a COLD START (aka "the big chill").
     It is recommended that you save PSWDM.100 to cassette or disk after the 
machine code is loaded and erase it from RAM.  This will prevent the 
possibility of anyone using it to change your id code while the machine is on 
and unattended.  You can load the program back into RAM and run it whenever 
you wish to change the code.
    To use PW.CO, just run the program FROM THE MENU when you're finished 
using your Model 100 (make sure HIMEM is set at or below 62710).  The program 
will IPL itself and turn off power to the computer.  When the power is turned 
back on, the program resumes and requests the ID code.  If an invalid code is 
entered, the user is so informed and given a second chance.  If an incorrect 
code is entered the second time, or if 60 seconds have elapsed since the 
machine was turned on, the program recycles and turns the power back off to 
prevent unauthorized access to your files.  When the correct ID is entered, 
the program proceeds to the menu.
===> Please be advised that experimenting with bypass strategies (e.g. pushing
the reset switch twice if the program is IPLing after a warm restart) may lead
to mangling of your RAM files and/or a cold start (i.e. loss of all data in 
RAM).  Therefore it is STRONGLY urged that you back up all your files before 
playing code-buster.
    A listing of the 8085 assembly mnemonics for PW.CO (PSWDM.ASM), with 
comments, is also available on DL4.  If you have an assembler, you can use it 
to relocate or modify the program.  If you use Bob Jack's assembler on this 
SIG, you will have to poke the ASCII strings into memory using the monitor or 
BASIC after assembling the mnemonics, or substitute a lot of DBs for each DS 
pseudo-op in the listing.  If you're normally hard-pressed for RAM space, the 
program can be shortened substantially by removing the "frills" (i.e. the 
initial greeting and the 2nd chance at the password).
     If you are not a machine-code programmer and would like a personalized 
version of this program, I can provide one for you which will display the 
following screen:

   This computer is the property of:
              Your Name
         Your Street Address
        Your town & zip code
          Your Phone Number
        [An optional message]

Enter Password > 

(This screen will of course require more RAM than the standard version.)
    Send me the above info via Easyplex and I will send you a downloadable 
test version which will run if you set the system date to 01/01/00 (the date 
of delivery depends on the demand).  If you are satisfied with the results, 
send me a certified check or money order for $20.00 and I'll send you the  
real thing.  Other modifications are negotiable.
     Acknowledgements to Bob Jack, Karl Chase, and Don Corbitt for their 
outstanding contributions to this DL, and to Russ Villanueva for suggesting 
improvements in the original version of PW.CO.
     Please let me know if you find a way to get around this program!
     Keith Bergendorff
     [72306,322]