PROGRAMME  =>  PASSWORD.ASM
	---------------------------

	This programme has been written to run under CP/M 2.2, but
	it may also run under earlier versions.   I'm not sure as
	I only own CP/M 2.2 so I can't test it against the other
	versions.

	It uses Function 6 for input from the keyboard, which is
	not echoed to the screen during the time data is being input.
	This means that no-one can (easily) see what has been entered
	by the operator when the disk is first logged on.

	The purpose of the programme is to make a user enter both
	his/her name, then a code, before the disk will boot up.
	If either the name of the user is not authorised or he/she
	fails to enter the correct code number (Note: 3 tries are
	allowed for each), then the computer keyboard is locked up
	and no further entries are possible without

		A. Turning off the terminal, and then turning it on
		   again to unlock the keyboard; or

		B. Re-booting the computer with RESET.

	In the first instance, the PASSWORD programme will be found
	to be still active, so the user gains nothing unless he/she
	can work out the passwords required.   In the second instance
	the keyboard is still locked-up so no data entries can be
	made.

	Note the reason why this was done is because it is necessary
	to install PASSWORD.COM to be called up on "autoboot" both
	from a cold start and from a warm start.   If this wasn't
	done then a knowlegable CP/M user could just turn off the
	terminal when it locks up....turn it on again and bypass
	PASSWORD by using CONTROL-C.

	The sample programme supplied as  PASSWORD.COM uses the
	entry "NAME" (or "name", either case is admissible [Line
	224]) in answer to the first question and "123" ("number",
	Line 225) in answer to the second.
	You can change either one, in PASSWORD.ASM, to suit your own
	requirements and then re-assemble the programme with ASM.COM.

	I have used ASM because EVERYBODY has this, it comes "free"
	with CP/M 2.2.   Only those who have purchased them
	separately have macro assemblers such as "MAC".   Please
	yourself how many digits (or digits and letters) you use
	for the code number (Line 225), but 3 or 4 should be more
	than enough.   This gives thousands of possible combinations
	so that it would take a lot of time for some-one to crack the
	code randomly.

	One thing I have done, because you don't want to go through
	the hassle of entering both your name and a code number each
	time a warm boot is performed, is to give a "bypass" code.
	In the demonstration case it is CONTROL-Z (Line 10).
	You will want to change it to something a bit more obscure
	to stop the casual user from accidently by-passing the
	entry sequence.

	The last thing to note about the programme is that I have
	used some "tricks" to save it from performing a warm boot
	on (successful) exit.   It is OK to do this because it
	doesn't overwrite the CCP so you won't clobber anything by
	calling up PASSWORD on autoboot.

	To install PASSWORD.COM in your BIOS so it will be called
	up on autoboot, the best method is to use "DUU.COM" to
	make the change.   A very good explanation on this can be
	found in

		User's Guide to CP/M Systems and Software,
		Volume 1, No. 4, June 1983; pages 62 and 63

	To those who don't own a copy the procedure is to put your
	system disk in drive A, and the disk to be PASSWORD-ed into
	drive B.   It should have PASSWORD.COM on it.   Single disk
	system users (ARE there any?) will have to do it all in
	drive A.

	Then enter

	     duu <RETURN>
	     lb		        (load drive B)
	     t2;s1;d            (view Track 2, sector 1.   See the
		                 Attachment [hard copy only, its too
	                         long to type into this note] to see
	                         what this looks like on my system)
	     ca8,PASSWORD<0>;w  (write PASSWORD into the 8 spaces
	                         from 08h to 0fh, and a full stop
	                         at 10h)
	     ch7,8;w            (write "8" into byte 06h)
	     d <RETURN>         (view the changes)
	     x <RETURN>         (return to CP/M)
	     
	     
	At the moment the programme is only for ONE user but it would
	be very easy to alter the first section to allow several users
	to log on, each with his/her own ID number.   All you need is
	a look-up table for the ID number depending on which user's
	name is correct.   Either that, or allow multiple names to log
	on but only have the one ID number.

	If either scheme is done, then it might be better to log on each
	user into a different user area.   It wouldn't take much effort to
	put all the system files in the "USER 0" area, and then have
	User 1, User 2,...User n, each with pointers to the system files
	so they could call up the COM files from their individual areas.

	Anyway, I haven't done this but it could be done if anyone has
	a multiple-user system and wants to keep things separate.

	Use LIST.COM to print out this file if you want a hard copy.
	I've supplied a copy with the disk I am submitting to the User
	Group.

	I hope the programme proves useful.   It is freely available for
	NON-COMMERCIAL use, but I'd appreciate getting paid for my efforts
	if anyone wants to use it in a commercial package.

	Phil Cogar,
	P.O. Box 364,                   39 Kalang Road,
	Narrabeen,                      Elanora Heights,
	N.S.W.   AUSTRALIA  2101
	------------------------
	Telephone: 913-7118