SAFRAM6.DOC
				Feb 22, 1988

Copyright 1988 by Roy Lipscomb, Logic Associates, Chicago
Permission hereby granted only for non-fee copying and distribution.


SAFRAM6.ASM:  []  Restores SAFRAM's compatibility with $$$.SUB files.

	      []  Allows SAFRAM to be de-installed, via "SAFRAM OFF".

	      []  More reliably detects an already-active SAFRAM module.


*******************************************************************************

FUNCTIONS
---------

	[]  Speeds up warmboot and "disk-system reset" functions by not
	    reloading CP/M and by not logging in drive A until needed.

	    (The above feature is standard for CP/M 2.2.  Clones of CP/M can
	    take advanatage of this feature by customizing the variable
	    "offsetcdk" in SAFRAM6.ASM.)

	[]  Acts as a buffer between TSR's that do not easily tolerate other
	    TSR's.

	[]  Creates a "safe ram" harbor below the CCP in which data or programs
	    are protected from being overwritten, even after warmboots.

	[]  Makes it possible to install BDOS and/or BIOS extensions below the
	    CCP instead of above the BIOS.  This saves space by letting such
	    extensions be installed in RAM only as needed.  This also makes it
	    possible to install extensions that are too long to reside in the
	    BIOS on the system tracks of the boot disk.


*******************************************************************************

BACKGROUND
----------

	Various utility modules or "traps" install themselves
	just below the CCP before they begin operation.  This
	allows other programs to load and execute normally,
	without overlaying and disrupting operation of the traps.

	Essential to this technique is altering RAM memory locations
	6 and 7 to point to the start of the trap.  This is necessary
	because 6/7 tells the next program what the upper end of the
	available work space is.

	This technique has been hobbled by the fact that warmboot
	alters the 6/7 contents back to their original coldboot
	value.  This strips away the module's protection.

	SAFRAM operates by protecting the contents of 6/7 from being
	changed back to its original coldboot value.  This protection
	lasts until the reset button is pushed, or until SAFRAM is
	explicitly disabled by the user.


*******************************************************************************

INSTALLATION
------------

	SAFRAM allows two modes of installation.

		1)  Executed without parameters, SAFRAM will secure the
		    current address in location 6/7 (or will secure
		    the CCP if 6/7 points higher than the CCP start).

		    Example:		A>SAFRAM

		2)  Executed with a four-character hex address as its
		    parameter, SAFRAM will secure that address.

		    Example:		A>SAFRAM A000


	Installed, the SAFRAM resident module occupies about 300 bytes of
	RAM.  Each additional execution of SAFRAM will add another 3 bytes
	of overhead.  SAFRAM also makes the CCP (2K in size) stay resident.

	NOTE:   SAFRAM will not install unless the CCP is resident and intact.
		Since DDT normally overlays the CCP, SAFRAM will normally
		refuse to execute under DDT.

		If you wish to load SAFRAM under DDT, first execute some
		utility that protects the CCP.  Besides SAFRAM itself, one
		such public-domain utility is DDTZ.


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DE-INSTALLATION
---------------

	To deinstall SAFRAM,

		1)  Type--		SAFRAM OFF<cr>

					where "<cr>" means "carriage return"

	   or   2)  Press the system-reset button.


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BUFFERING BETWEEN TSRs
----------------------

	Most programs are active only between the time you load them and the
	time you "warmboot" (exit back to the operating-system command line
	without pressing the reset button).

	A terminate-and-stay-resident (TSR) utility is one that relocates to
	the top of the program-memory area, and then attaches itself into the
	operating system.  This allows the utility to remains active even after
	its main portion terminates and you execute other programs.

	Some TSRs crash if any other TSR happens to be active.  This results
	when the late-comer TSR uses a relocating-and-attaching technique
	that is oblivious to the possibility that any other TSR may be present.

	Recoding of the "ill-behaved" TSR is the best solution.  There are
	relocating-and-attaching techniques that can make any TSR "friendly."
	But recoding is often unfeasible.

	In such a case, the following "work around" may allow two otherwise
	incompatible TSRs to co-exist in memory:

		Step 1.  Execute one of the TSRs.
		Step 2.  Execute SAFRAM6.
		Step 3.  Execute the other TSR.
		Step 4.  Execute SAFRAM6.

	The above technique can be employed to cover not only two, but also
	three, four, or any number of TSRs.

	Though this technique is not foolproof, it has been found to create
	"compatibility" in enough situations that it is worth trying at least
	as a last resort.


*******************************************************************************

THEORY OF OPERATION
-------------------

	At initial installation, the SAFRAM trap module relocates itself to
	just below the CCP (or the currently protected module), and protects
	both itself and whatever is above it in RAM.

	In simplest terms, SAFRAM operates by patching two traps
	into the BIOS jump table.

		* The "WARMBOOT" trap sets a flag indicating that a
		  warmboot has been requested; then simulates a normal
		  warmboot; and jumps to the already resident CCP.

		* The "CONSOLE OUT" trap checks the warmboot flag.
		  If the flag is set, this trap resets the flag and
		  (if this option was set at assembly time) notifies
		  the user of the presence of SAFRAM.  This trap
		  finishes by jumping to the normal CONOUT routine.

	Starting with version 5, SAFRAM also traps each "reset system" function
	call and converts it to "reset all disks".  ("System reset" always logs
	in drive A.  "Reset all disks" doesn't, and so saves time.)

	Version 6 also monitors "open file," "close file," "find file," and
	"erase file" for activity on file "$$$.SUB".  "Erase file" causes
	SAFRAM to turn off the CCP "$$$.SUB-active" flag.  The other functions,
	when successful, cause SAFRAM to turn the flag on.

	Note:	This flag-setting/resetting takes place only if SAFRAM can
		assure itself at run time that it has in fact located the
		"$$$.SUB-active" flag within the CCP.



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ASSEMBLING
----------

	This source uses the LINK pseudo-operation featured in
	Ward Christensen's LASM.COM (available on RCPM's) and
	its predecessor LINKASM.COM (available from CPM Users
	Group as 36.11 and 36.12).  This feature is used here to
	link SAFRAM6.ASM to itself, and thus introduce two
	(partial) copies to the assembler.  The two copies are used
	by the resultant SAFRAM6.COM to produce a relocatable module.

	If neither of the above assemblers is available, this
	source can be assembled in a more roundabout fashion.

	First, delete these three statements from the end of
	SAFRAM6.ASM:

		if	not copy1
		link	safram6
		endif

	Next, execute the following commands:

		PIP  SAFRAMX.ASM=SAFRAM6.ASM,SAFRAM6.ASM
		;The next step can use ASM.COM or any standard assembler.
		ASM  SAFRAMX
		LOAD SAFRAMX
		ERA  SAFRAMX.HEX
		REA  SAFRAMX.PRN

	The resulting SAFRAMX.COM in equivalent in every respect to
	SAFRAM6.COM.


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CUSTOMIZING
-----------

	Customizing of SAFRAM6.ASM is accomplished via these variables:

	VARIABLE    DEFAULT	COMMENT
	--------    -------     -------

	BOOT	      0		0 for standard CP/M.

	NOTIFY	     yes	"yes" to receive verification of the currently
				secured address during each warmboot.

	PAGEBND	     no		Lower SAFRAM6 module to page boundary+6?
				If no, SAFRAM6 fits snug against TPA ceiling.

	OFSETCD	    342H	Offset to current-drive storage byte in bdos.

				[]  If your system IS CP/M 2.2,
						   --
				    *	Do NOT change the value of this
					variable.  It allows SAFRAM6 to speed
					up warmboots.

				[]  If your system IS NOT CP/M 2.2,
						   ------
				    *  If you customize this value for your
				       BDOS, SAFRAM6 will speed up warmboots.

				    *  If you do not customize this value,
				       SAFRAM6 will not speed up warmboots.


*******************************************************************************

APPLICATION NOTES
-----------------

[]  Some high-memory modules do not protect themselves by changing
	locations 6/7.  To secure such a module, use the explicit-address
	option of SAFRAM6.  (See INSTALLATION above.)

[]  Self-relocating utility modules that will be protected by SAFRAM6
	should insure that they do not overlay the CCP.

[]  To inspect the CCP using DDT (which normally overlays the CCP),
	execute SAFRAM6 before invoking DDT.  Thereafter, the CCP will
	remain intact when DDT is loaded.

[]  To install and then protect DDT, use this command sequence:

		SAFRAM6			<--to secure the CCP.
		DDT SAFRAM6.COM
		-G			<--to secure DDT.

	DDT will now remain resident until the system is reset.

	This allows you to instantly return to DDT anytime the system is
	waiting for console-input, even in the midst of another program.
	(Instant return to DDT requires the installation of the public-
	domain BACK2DDT or a similar utility.  BACK2DDT is available from
	many RCP/M's and from Logic Associates.)


*******************************************************************************

MESSAGES
--------

The following message is displayed at each logon:


	 DDDDDD  DDDD   DDDDD DDDDD    DDDD   DD    DD
	DDD     DD  DD  DD    DD  DD  DD  DD  DDD  DDD
	 DDDDD  DD  DD  DDDD  DDDDD   DD  DD  DDDDDDDD
	   DDDD DDDDDD  DD    DD DD   DDDDDD  DD DD DD
	DDDDDD  DD  DD  DD    DD  DD  DD  DD  DD    DD

	SAFRAM 6.0                             2/25/88
	(C) Copyright 1988, Logic Associates, Chicago

	   * Acts as buffer between ill-behaved TSRs.
	   * Speeds up warmboot and "reset all disks".
	   * Creates safe RAM partition below the CCP.

	[] "SAFRAM xxxx" --protects hex address xxxx.

	[] "SAFRAM"      --protects CCP and all TSRs.

	[] "SAFRAM OFF"  --removes SAFRAM.

	[]  Multiple re-executions are permitted.
	----------------------------------------------


After the above logon message, one of the		COMMENTS
messages below will be displayed:			--------


***               Installed.               ***	 <--SAFRAM newly installed.


***              Reassigned.               ***	 <--Previously installed SAFRAM
						    now protects new address.

***             De-installed.              ***	 <--SAFRAM newly removed.


*** Abort:  Valid range is xxxxH to xxxxH. ***	 <--User-requested installation
						    addr not within free RAM.

***       Abort:  SAFRAM not present.      ***	 <--Cannot remove SAFRAM; it's
						    not installed.

***      Abort:  Unable to locate CCP.     ***	 <--Cannot find location to
						    move SAFRAM into.

***  Abort:  Cannot de-install at present. ***	 <--SAFRAM's patch points are
						    overlayed by some other
						    utilities patches at the
						    moment.

*** Abort:  Conflicting versions of SAFRAM.***   <--Can't reassign or remove
						    SAFRAM unless re-executing
						    installed version.



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OTHER SOFTWARE
--------------

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			Logic Associates
			1433 W. Thome
			Chicago, IL 60660
			(312) 274-0531

	Thank you, and we hope you enjoy SAFRAM!

******************************************************************************
									(end)