diff --git a/Source/CBIOS/cbios.asm b/Source/CBIOS/cbios.asm
index 97771883..0b06d19c 100644
--- a/Source/CBIOS/cbios.asm
+++ b/Source/CBIOS/cbios.asm
@@ -2929,6 +2929,12 @@ DRV_INIT3:
 	RET
 ;
 DRV_INIT3A:
+	; CHECK FOR HARD DISK REMOVABLE CARTRIDGE DRIVES
+	CP	DIODEV_PPA		; PPA (ZIP DRIVE) IS REMOVABLE
+	JR	Z,DRV_INIT3B		; IF SO, SKIP MEDIA CHECK
+	CP	DIODEV_IMM		; IMM (ZIP DRIVE) IS REMOVABLE
+	JR	Z,DRV_INIT3B		; IF SO, SKIP MEDIA CHECK
+
 	; CHECK FOR ACTIVE AND RETURN IF NOT
 	PUSH	DE			; SAVE DE (HARD DISK VOLUME COUNTER)
 	PUSH	HL			; SAVE DRIVE LIST PTR
@@ -2944,6 +2950,7 @@ DRV_INIT3A:
 
 	RET	NZ			; IF NO MEDIA, JUST RETURN
 
+DRV_INIT3B:
 	; IF ACTIVE...
 	LD	(HL),C			; SAVE UNIT NUM IN LIST
 	INC	HL			; BUMP PTR
diff --git a/Source/CPM3/boot.z80 b/Source/CPM3/boot.z80
index ce3fef1b..05dcb4f6 100644
--- a/Source/CPM3/boot.z80
+++ b/Source/CPM3/boot.z80
@@ -181,6 +181,12 @@ dinit3:
 	ret
 ;
 dinit3a:
+	; check for hard disk removable cartridge drives
+	cp	0A0h			; ppa (zip drive) is removable
+	jr	z,dinit3b		; if so, skip media check
+	cp	0B0h			; imm (zip drive) is removable
+	jr	z,dinit3b		; if so, skip media check
+
 	; check for active and return if not
 	push	de			; save de (hard disk volume counter)
 	push	hl			; save drive list ptr
@@ -195,7 +201,8 @@ dinit3a:
 	pop	de			; restore de
 	
 	ret	nz			; if no media, just return
-	
+
+dinit3b:
 	; if active...
 	ld	(hl),c			; save unit num in list
 	inc	hl			; bump ptr
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index be5110c8..4af09d42 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -6786,7 +6786,6 @@ PS_PRTDC:
 	RES	7,D			; CLEAR LBA BIT
 	LD	B,11			; 11 BIT SHIFT TO CONVERT BLOCKS --> MB
 	CALL	SRL32			; RIGHT SHIFT
-	;CALL	PRTDEC			; PRINT LOW WORD IN DECIMAL (HIGH WORD DISCARDED)
 	CALL	PRTDEC32		; PRINT DWORD IN DECIMAL
 	PRTS("MB$")			; PRINT SUFFIX
 	CALL	PC_COMMA
@@ -6801,7 +6800,6 @@ PS_PRTDC1:
 	RES	7,D			; CLEAR LBA BIT
 	LD	B,1			; 11 BIT SHIFT TO CONVERT BLOCKS --> MB
 	CALL	SRL32			; RIGHT SHIFT
-	;CALL	PRTDEC			; PRINT LOW WORD IN DECIMAL (HIGH WORD DISCARDED)
 	CALL	PRTDEC32		; PRINT DWORD IN DECIMAL
 	PRTS("KB$")			; PRINT SUFFIX
 	CALL	PC_COMMA
diff --git a/Source/HBIOS/imm.asm b/Source/HBIOS/imm.asm
index 7c1b63ec..df3e8301 100644
--- a/Source/HBIOS/imm.asm
+++ b/Source/HBIOS/imm.asm
@@ -13,6 +13,7 @@
 ; MUCH OF THE CODE IS DERIVED FROM FUZIX (ALAN COX).
 ;
 ; 5/23/2023 WBW - INITIAL RELEASE
+; 5/26/3023 WBW - CLEAN UP, LED ACTIVITY
 ;
 ;=============================================================================
 ;
@@ -43,25 +44,16 @@
 ;
 ; TODO:
 ;
-; - TIMEOUT IS INFINITE!!!
-;
-; - ASSIGN DRIVE LETTERS EVEN WHEN NO MEDIA AT BOOT
+; - CLEAN UP WAIT LOOP STUFF
 ;
 ; - OPTIMIZE READ/WRITE LOOPS
 ;
-; - COMMENT MORE OF THE CODE
-;
-; - THERE ARE CURRENTLY NO BUFFER OVERRUN CHECKS.  WE ASSUME SCSI
-;   DEVICES WILL SEND/REQUEST THE EXPECTED NUMBER OF BYTES.
-;
-; - MAKE THE MG014 STATUS LED DO SOMETHING USEFUL?
-;
 ; NOTES:
 ;
-; - THIS DRIVER IS FOR THE ZIP DRIVE EMM INTERFACE.  IT WILL SIMPLY
+; - THIS DRIVER IS FOR THE ZIP DRIVE IMM INTERFACE.  IT WILL SIMPLY
 ;   FAIL TO EVEN RECOGNIZE A ZIP DRIVE WITH THE OLDER PPA INTERFACE.
 ;   THERE DOES NOT SEEM TO BE A WAY TO VISUALLY DETERMINE IF A ZIP
-;   DRIVE IS EMM OR PPA.  SIGH.
+;   DRIVE IS IMM OR PPA.  SIGH.
 ;
 ; - THERE ARE SOME HARD CODED TIMEOUT LOOPS IN THE CODE.  THEY ARE
 ;   WORKING OK ON A 7 MHZ Z80.  THEY ARE LIKELY TO NEED TWEAKING ON
@@ -76,6 +68,9 @@
 ;   THE STANDARD IBM PARALLEL PORT WHICH NECESSITATES A BUNCH OF EXTRA
 ;   BIT FIDDLING ON EVERY READ.
 ;
+; - SOME OF THE DATA TRANSFERS HAVE NO BUFFER OVERRUN CHECKS.  IT IS
+;   ASSUMED SCSI DEVICES WILL SEND/REQUEST THE EXPECTED NUMBER OF BYTES.
+;
 ; IMM PORT OFFSETS
 ;
 IMM_IODATA	.EQU	0		; PORT A, DATA, OUT
@@ -87,17 +82,6 @@ IMM_IOSETUP	.EQU	3		; PPI SETUP
 ;
 IMM_SELF	.EQU	7
 IMM_TGT		.EQU	6
-;
-; SCSI COMMAND CODES
-;
-SCSI_CMD_READ	.EQU	$08
-SCSI_CMD_INQ	.EQU	$12
-SCSI_CMD_TEST	.EQU	$00
-SCSI_CMD_START	.EQU	$1B
-SCSI_CMD_SENSE	.EQU	$03
-SCSI_CMD_WRITE	.EQU	$0A
-SCSI_CMD_RDCAP	.EQU	$25
-
 ;
 ; IMM DEVICE STATUS
 ;
@@ -223,12 +207,18 @@ IMM_DETECT:
 	LD	C,A			; MOVE TO C FOR I/O
 	LD	A,$82			; CONFIG A OUT, B IN, C OUT
 	OUT	(C),A			; DO IT
-	CALL	DELAY
+	CALL	DELAY			; BRIEF DELAY FOR GOOD MEASURE
 ;
+	; WE USE THIS SEQUENCE TO DETECT AN ACTUAL IMM DEVICE ON THE
+	; PARALLEL PORT.  THE VALUES RECORDED IN THE FINAL CALL TO
+	; IMM_DISCONNECT ARE USED TO CONFIRM DEVICE PRESENCE.
+	; NO ACTUAL SCSI COMMANDS ARE USED.
 	CALL	IMM_DISCONNECT
 	CALL	IMM_CONNECT
 	CALL	IMM_DISCONNECT
 ;
+	; THE IMM_SN VALUES ARE RECORDED IN THE CPP ROUTINE USED BY
+	; IMM_CONNECT/DISCONNECT.
 	; EXPECTING S1=$B8, S2=$18, S3=$38
 	LD	A,(IMM_S1)
 	CP	$B8
@@ -273,18 +263,18 @@ IMM_DEFMED:
 ;
 ;
 IMM_READ:
-	CALL	HB_DSKREAD
-	LD	A,SCSI_CMD_READ
-	LD	(IMM_CMD_RW),A
-	JP	IMM_IO
+	CALL	HB_DSKREAD		; HOOK DISK READ CONTROLLER
+	LD	A,SCSI_CMD_READ		; SETUP SCSI READ
+	LD	(IMM_CMD_RW),A		; AND SAVE IT IN SCSI CMD
+	JP	IMM_IO			; DO THE I/O
 ;
 ;
 ;
 IMM_WRITE:
-	CALL	HB_DSKREAD
-	LD	A,SCSI_CMD_WRITE
-	LD	(IMM_CMD_RW),A
-	JP	IMM_IO
+	CALL	HB_DSKREAD		; HOOK DISK WRITE CONTROLLER
+	LD	A,SCSI_CMD_WRITE	; SETUP SCSI WRITE
+	LD	(IMM_CMD_RW),A		; AND SAVE IT IN SCSI CMD
+	JP	IMM_IO			; DO THE I/O
 ;
 ;
 ;
@@ -292,7 +282,7 @@ IMM_IO:
 	LD	(IMM_DSKBUF),HL		; SAVE DISK BUFFER ADDRESS
 	CALL	IMM_CHKERR		; CHECK FOR ERR STATUS AND RESET IF SO
 	JR	NZ,IMM_IO3		; BAIL OUT ON ERROR
-;	
+;
 	; SETUP LBA
 	; 3 BYTES, LITTLE ENDIAN -> BIG ENDIAN
 	LD	HL,IMM_CMD_RW+1		; START OF LBA FIELD IN CDB (MSB)
@@ -307,11 +297,11 @@ IMM_IO:
 	INC	HL
 ;
 	; DO SCSI IO
-	LD	DE,(IMM_DSKBUF)
-	LD	BC,512
-	LD	HL,IMM_CMD_RW
-	CALL	IMM_RUNCMD
-	CALL	Z,IMM_CHKCMD
+	LD	DE,(IMM_DSKBUF)		; DISK BUFFER TO DE
+	LD	BC,512			; ONE SECTOR, 512 BYTES
+	LD	HL,IMM_CMD_RW		; POINT TO READ/WRITE CMD TEMPLATE
+	CALL	IMM_RUNCMD		; RUN THE SCSI ENGINE
+	CALL	Z,IMM_CHKCMD		; IF EXIT OK, CHECK SCSI RESULTS
 	JR	NZ,IMM_IO2		; IF ERROR, SKIP INCREMENT
 	; INCREMENT LBA
 	LD	A,IMM_LBA		; LBA OFFSET
@@ -343,7 +333,7 @@ IMM_STATUS:
 ;
 ;
 IMM_RESET:
-	JP	IMM_INITDEV
+	JP	IMM_INITDEV		; JUST (RE)INIT DEVICE
 ;
 ;
 ;
@@ -363,7 +353,7 @@ IMM_MEDIA:
 	OR	A			; SET FLAGS
 	JR	Z,IMM_MEDIA1		; JUST REPORT CURRENT STATUS AND MEDIA
 ;
-	CALL	IMM_RESET		; RESET IMM INTERFACE
+	CALL	IMM_RESET		; RESET INCLUDES MEDIA CHECK
 ;
 IMM_MEDIA1:
 	LD	A,(IY+IMM_STAT)		; GET STATUS
@@ -418,64 +408,81 @@ IMM_GEOM:
 ; FUNCTION SUPPORT ROUTINES
 ;=============================================================================
 ;
+; OUTPUT BYTE IN A TO THE DATA PORT
+;
 IMM_WRITEDATA:
-	LD	C,(IY+IMM_IOBASE)
-	OUT	(C),A
-	CALL	DELAY
-	RET
+	LD	C,(IY+IMM_IOBASE)	; DATA PORT IS AT IOBASE
+	OUT	(C),A			; WRITE THE BYTE
+	;CALL	DELAY			; IS THIS NEEDED???
+	RET				; DONE
 ;
 ;
 ;
 IMM_WRITECTRL:
-	XOR	$0B
-	LD	C,(IY+IMM_IOBASE)
-	INC	C
+	; IBM PC INVERTS ALL BUT C2 ON THE BUS, MG014 DOES NOT.
+	; BELOW TRANSLATES FROM IBM -> MG014.	IT ALSO INVERTS THE
+	; MG014 LED SIMPLY TO MAKE IT EASY TO KEEP LED ON DURING
+	; ALL ACTIVITY.
+	XOR	$0B | $80		; HIGH BIT IS MG014 LED
+	LD	C,(IY+IMM_IOBASE)	; GET BASE IO ADDRESS
+	INC	C			; BUMP TO CONTROL PORT
 	INC	C
-	OUT	(C),A
-	CALL	DELAY
-	RET
+	OUT	(C),A			; WRITE TO CONTROL PORT
+	;CALL	DELAY			; IS THIS NEEDED?
+	RET				; DONE
 ;
+; READ THE PARALLEL PORT INPUT LINES (STATUS) AND MAP SIGNALS FROM
+; MG014 TO IBM STANDARD.  NOTE POLARITY CHANGE REQUIRED FOR BUSY.
 ;
+; 	MG014		IBM PC
+;	--------	--------
+;	0: /ACK		6: /ACK
+;	1: BUSY		7: /BUSY
+;	2: POUT		5: POUT
+;	3: SEL		4: SEL
+;	4: /ERR		3: /ERR
 ;
 IMM_READSTATUS:
-	LD	C,(IY+IMM_IOBASE)
-	INC	C
-	IN	A,(C)
+	LD	C,(IY+IMM_IOBASE)	; IOBASE TO C
+	INC	C			; BUMP TO STATUS PORT
+	IN	A,(C)			; READ IT
 	LD	C,0			; INIT RESULT
-;	
-	BIT	0,A			; ACK = $01
+;
+	; SHUFFLE BITS
+	BIT	0,A			; 0: /ACK
 	JR	Z,IMM_READSTATUS1
-	SET	6,C			; $40
+	SET	6,C			; 6: /ACK
 ;
 IMM_READSTATUS1:
-;	
-	BIT	1,A			; BUSY = $02
-	JR	NZ,IMM_READSTATUS2
-	SET	7,C			; $80
+;
+	BIT	1,A			; 1: BUSY
+	JR	NZ,IMM_READSTATUS2	; POLARITY CHANGE!
+	SET	7,C			; 7: /BUSY
 ;
 IMM_READSTATUS2:
-;	
-	BIT	2,A			; PAPER = $04
+;
+	BIT	2,A			; 2: POUT
 	JR	Z,IMM_READSTATUS3
-	SET	5,C			; $20
+	SET	5,C			; 5: POUT
 ;
 IMM_READSTATUS3:
-;	
-	BIT	3,A			; SELECT = $08
+;
+	BIT	3,A			; 3: SEL
 	JR	Z,IMM_READSTATUS4
-	SET	4,C			; $10
+	SET	4,C			; 4: SEL
 ;
 IMM_READSTATUS4:
-;	
-	BIT	4,A			; FAULT = $10
+;
+	BIT	4,A			; 4: /ERR
 	JR	Z,IMM_READSTATUS5
-	SET	3,C			; $08
+	SET	3,C			; 3: /ERR
 ;
 IMM_READSTATUS5:
-	LD	A,C
+	LD	A,C			; RESULT TO A
 	RET
 ;
-;
+; SIGNAL SEQUENCE TO CONNECT/DISCONNECT
+; VALUE IN A IS WRITTEN TO DATA PORT DURING SEQUENCE
 ;
 IMM_CPP:
 	PUSH	AF
@@ -516,7 +523,7 @@ IMM_CPP:
 	; CONNECT: S1=$B8 S2=$18 S3=$30
 	; DISCONNECT: S1=$B8 S2=$18 S3=$38
 ;
-#IF (IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nCPP: S1=$")
 	LD	A,(IMM_S1)
 	CALL	PRTHEXBYTE
@@ -535,7 +542,7 @@ IMM_S1	.DB	0
 IMM_S2	.DB	0
 IMM_S3	.DB	0
 ;
-;
+; SEQUENCE TO CONNECT TO DEVICE ON PARALLEL PORT BUS.
 ;
 IMM_CONNECT:
 	LD	A,$E0
@@ -546,14 +553,20 @@ IMM_CONNECT:
 	CALL	IMM_CPP
 	RET
 ;
-;
+; SEQUENCE TO DISCONNECT FROM DEVICE ON PARALLEL PORT BUS.
+; THE FINAL IMM_WRITECTRL IS ONLY TO TURN OFF THE MG014 STATUS LED.
 ;
 IMM_DISCONNECT:
 	LD	A,$30
 	CALL	IMM_CPP
-	RET
 ;
+	; TURNS OFF MG014 LED
+	LD	A,$8C
+	CALL	IMM_WRITECTRL
+;
+	RET
 ;
+; INITIATE A SCSI BUS RESET.
 ;
 IMM_RESETPULSE:
 	LD	A,$04
@@ -574,10 +587,10 @@ IMM_RESETPULSE:
 	CALL	IMM_WRITECTRL
 	RET
 ;
-;
+; SCSI SELECT PROCESS
 ;
 IMM_SELECT:
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nSELECT: $")
 #ENDIF
 	LD	A,$0C
@@ -598,13 +611,14 @@ IMM_SELECT1:
 IMM_SELECT2:
 	LD	A,$04
 	CALL	IMM_WRITECTRL
+	; PLACE HOST AND TARGET BIT ON DATA BUS
 	LD	A,$80 | (1 << IMM_TGT)
 	CALL	IMM_WRITEDATA
-	CALL	DELAY
+	CALL	DELAY			; CONFIRM DELAY TIME?
 	LD	A,$0C
 	CALL	IMM_WRITECTRL
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	IMM_READSTATUS
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
@@ -613,7 +627,7 @@ IMM_SELECT2:
 	LD	A,$0D
 	CALL	IMM_WRITECTRL
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	IMM_READSTATUS
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
@@ -623,12 +637,12 @@ IMM_SELECT2:
 ;
 IMM_SELECT3:
 	CALL	IMM_READSTATUS
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 	AND	$08
-	JR	NZ,IMM_SELECT4		; IF CLEAR, MOVE ON
+	JR	NZ,IMM_SELECT4		; IF SET, MOVE ON
 	DEC	HL
 	LD	A,H
 	OR	L
@@ -642,99 +656,123 @@ IMM_SELECT4:
 	XOR	A
 	RET
 ;
+; SEND SCSI CMD BYTE STRING.  AT ENTRY, HL POINTS TO START OF
+; COMMAND BYTES.  THE LENGTH OF THE COMMAND STRING MUST PRECEED
+; THE COMMAND BYTES (HL - 1).
 ;
+; NOTE THAT DATA IS SENT AS BYTE PAIRS!  EACH LOOP SENDS 2 BYTES.
+; DATA OUTPOUT IS BURSTED (NO CHECK FOR BUSY).  SEEMS TO WORK FINE.
 ;
 IMM_SENDCMD:
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nSENDCMD:$")
 #ENDIF
 ;
-	LD	HL,0
+	DEC	HL		; BACKUP TO LENGTH BYTE
+	LD	B,(HL)		; PUT IN B FOR LOOP COUNTER
+;
+#IF (IMMTRACE >= 3)
+	LD	A,B
+	CALL	PC_SPACE
+	CALL	PRTHEXBYTE
+	PRTS(" BYTES$")
+#ENDIF
+;
+	INC	HL		; BACK TO FIRST CMD BYTE
 IMM_SENDCMD1:
-	PUSH	HL
-	CALL	IMM_WAITDONE
-	POP	HL
-	CP	$A8
-	JR	NZ,IMM_SENDCMD2
 	LD	A,$04
 	CALL	IMM_WRITECTRL
-	LD	A,(DE)
+	LD	A,(HL)		; LOAD CMD BYTE
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
-	CALL	IMM_WRITEDATA
-	INC	DE
-	INC	HL
+	CALL	IMM_WRITEDATA	; PUT IT ON THE BUS
+	INC	HL		; BUMP TO NEXT BYTE
+	DEC	B		; DEC LOOP COUNTER
 	LD	A,$05
 	CALL	IMM_WRITECTRL
-	LD	A,(DE)
+	LD	A,(HL)		; LOAD CMD BYTE
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
-	CALL	IMM_WRITEDATA
-	INC	DE
-	INC	HL
+	CALL	IMM_WRITEDATA	; PUT IT ON THE BUS
+	INC	HL		; BUMP TO NEXT BYTE
 	LD	A,$00
 	CALL	IMM_WRITECTRL
-	JR	IMM_SENDCMD1
+	DJNZ	IMM_SENDCMD1	; LOOP TILL DONE
 ;
 IMM_SENDCMD2:
 	LD	A,$04
 	CALL	IMM_WRITECTRL
-;
-#IF IMMTRACE >= 2)
-	CALL	PC_SPACE
-	CALL	PRTHEXWORDHL
-	PRTS(" BYTES$")
-#ENDIF
 ;
 	RET
 ;
+; WAIT FOR SCSI BUS TO BECOME READY WITH A TIMEOUT.
 ;
-;
-IMM_WAITBUSY:
-	LD	HL,500			; NORMAL TIMEOUT COUNTER
-;
-IMM_WAITBUSY_HL:			; VARIABLE TIMEOUT ENTRY
-	LD	A,$0C
-	CALL	IMM_WRITECTRL
-;
-IMM_WAITBUSY2:
+IMM_WAITLOOP:
 	CALL	IMM_READSTATUS
 	BIT	7,A
-	RET	NZ			; IF SET, MOVE ON
+	RET	NZ			; DONE, STATUS IN A
 	DEC	HL
 	LD	A,H
 	OR	L
-	; TODO: IMPLEMENT TIMEOUT!!!
-	;JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
-	JR	IMM_WAITBUSY2
+	RET	Z			; TIMEOUT
+	JR	IMM_WAITLOOP
 ;
+IMM_WAIT:
+	LD	HL,500			; GOOD VALUE???
+	LD	A,$0C
+	CALL	IMM_WRITECTRL
+	CALL	IMM_WAITLOOP
+	JP	Z,IMM_CMD_TIMEOUT	; HANDLE TIMEOUT
+	PUSH	AF
+	LD	A,$04
+	CALL	IMM_WRITECTRL
+	POP	AF
+	AND	$B8
+	RET				; RETURN W/ RESULT IN A
 ;
+; MAX OBSERVED IMM_WAITLOOP ITERATIONS IS $0116B3
 ;
-IMM_WAITDONE:
-	LD	HL,500			; NORMAL TIMEOUT COUNTER
+IMM_LONGWAIT:
+	LD	B,3			; VALUE???
+	LD	A,$0C
+	CALL	IMM_WRITECTRL
+IMM_LONGWAIT1:
+	LD	HL,0
+	CALL	IMM_WAITLOOP
+	JR	NZ,IMM_LONGWAIT2	; HANDLE SUCCESS
+	DJNZ	IMM_LONGWAIT1		; LOOP TILL COUNTER EXHAUSTED
+	JP	IMM_CMD_TIMEOUT		; HANDLE TIMEOUT
 ;
-IMM_WAITDONE_HL:			; VARIABLE TIMEOUT ENTRY
-	CALL	IMM_WAITBUSY_HL
-	AND	$B8
+IMM_LONGWAIT2:
 	PUSH	AF
 	LD	A,$04
 	CALL	IMM_WRITECTRL
-	POP	AF
-	RET
 ;
+#IF 0
+	CALL	PC_GT
+	LD	A,B
+	CALL	PRTHEXBYTE
+	CALL	PC_COLON
+	CALL	PRTHEXWORDHL
+#ENDIF
 ;
+	POP	AF
+	AND	$B8
+	RET				; RETURN W/ RESULT IN A
+;
+; PEROFRM SCSI BUS NEGOTIATION.  REQURIED PRIOR TO DATA READS.
 ;
 IMM_NEGOTIATE:
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nNEGO: $")
 #ENDIF
 	LD	A,$04
@@ -758,29 +796,28 @@ IMM_NEGOTIATE:
 ;
 	POP	AF
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
 	AND	$20
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PC_GT
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
-	CP	$20
+	CP	$20			; $20 MEANS DATA READY
 	JP	NZ,IMM_CMD_IOERR
 	RET
 ;
-;
+; GET A BYTE OF DATA FROM THE SCSI DEVICE.  THIS IS A NIBBLE READ.
+; BYTE RETURNED IN A.
 ;
 IMM_GETBYTE:
-	CALL	IMM_WAITBUSY
-	LD	A,$04
-	CALL	IMM_WRITECTRL
+	CALL	IMM_WAIT
 	LD	A,$06
 	CALL	IMM_WRITECTRL
 	CALL	IMM_READSTATUS
@@ -802,53 +839,62 @@ IMM_GETBYTE:
 	POP	AF
 	RET
 ;
+; GET A CHUNK OF DATA FROM SCSI BUS.  THIS IS SPECIFICALLY FOR
+; READ PHASE.  IF A LENGTH IS SPECIFIED (NON-ZERO HL), THEN THE
+; DATA IS BURST READ.  IF NO LENGTH SPECIFIED, DATA IS READ AS
+; LONG AS SCSI DEVICE WANTS TO CONTINUE SENDING (NO OVERRUN
+; CHECK IN THIS CASE).
+;
+; THIS IS A NIBBLE READ.
+;
 ; DE=BUFFER
 ; HL=LENGTH (0 FOR VARIABLE)
 ;
 IMM_GETDATA:
+	; BRANCH TO CORRECT ROUTINE
 	LD	A,H
-	OR	L
-	JR	NZ,IMM_GETDATALEN
+	OR	L			; IF ZERO
+	JR	NZ,IMM_GETDATALEN	; DO BURST READ
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nGETDATA:$")
 #ENDIF
 ;
 IMM_GETDATA1:
-	PUSH	HL
-	CALL	IMM_WAITDONE
-	POP	HL
-	CP	$98
-	JR	NZ,IMM_GETDATA2
+	PUSH	HL			; SAVE BYTE COUNTER
+	CALL	IMM_WAIT		; WAIT FOR BUS READY
+	POP	HL			; RESTORE BYTE COUNTER
+	CP	$98			; CHECK FOR READ PHASE
+	JR	NZ,IMM_GETDATA2		; IF NOT, ASSUME WE ARE DONE
 	LD	A,$04
 	CALL	IMM_WRITECTRL
 	LD	A,$06
 	CALL	IMM_WRITECTRL
-	CALL	IMM_READSTATUS
-	AND	$F0
-	RRCA
+	CALL	IMM_READSTATUS		; GET FIRST NIBBLE
+	AND	$F0			; ISOLATE BITS
+	RRCA				; AND SHIFT TO LOW NIBBLE
 	RRCA
 	RRCA
 	RRCA
-	PUSH 	AF
+	PUSH 	AF			; SAVE WORKING VALUE
 	LD	A,$05
 	CALL	IMM_WRITECTRL
-	CALL	IMM_READSTATUS
-	AND	$F0
-	POP	BC
-	OR	B
-	LD	(DE),A
-	INC	DE
-	INC	HL
+	CALL	IMM_READSTATUS		; GET SECOND NIBBLE
+	AND	$F0			; ISOLATE BITS
+	POP	BC			; RECOVER LOW NIBBLE
+	OR	B			; COMBINE
+	LD	(DE),A			; AND SAVE THE FULL BYTE VALUE
+	INC	DE			; NEXT BUFFER POS
+	INC	HL			; INCREMENT BYTES COUNTER
 	LD	A,$04
 	CALL	IMM_WRITECTRL
 	LD	A,$0C
 	CALL	IMM_WRITECTRL
-	JR	IMM_GETDATA1
+	JR	IMM_GETDATA1		; LOOP TILL DONE
 ;
 IMM_GETDATA2:
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXWORDHL
 	PRTS(" BYTES$")
@@ -858,7 +904,7 @@ IMM_GETDATA2:
 ;
 IMM_GETDATALEN:
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nGETDLEN:$")
 	CALL	PC_SPACE
 	CALL	PRTHEXWORDHL
@@ -870,31 +916,39 @@ IMM_GETDATALEN:
 IMM_GETDATALEN1:
 	LD	A,$06
 	CALL	IMM_WRITECTRL
-	CALL	IMM_READSTATUS
-	AND	$F0
-	RRCA
+	CALL	IMM_READSTATUS		; GET FIRST NIBBLE
+	AND	$F0			; ISOLATE BITS
+	RRCA				; MOVE TO LOW NIBBLE
 	RRCA
 	RRCA
 	RRCA
-	PUSH 	AF
+	PUSH 	AF			; SAVE WORKING VALUE
 	LD	A,$05
 	CALL	IMM_WRITECTRL
-	CALL	IMM_READSTATUS
-	AND	$F0
-	POP	BC
-	OR	B
-	LD	(DE),A
-	INC	DE
-	DEC	HL
+	CALL	IMM_READSTATUS		; GET SECOND NIBBLE
+	AND	$F0			; ISOLATE BITS
+	POP	BC			; RECOVER FIRST NIBBLE
+	OR	B			; COMBINE
+	LD	(DE),A			; SAVE FINAL BYTE VALUE
+	INC	DE			; NEXT BUFFER POS
+	DEC	HL			; DEC LOOP COUNTER
 	LD	A,$04
 	CALL	IMM_WRITECTRL
-	LD	A,H
+	LD	A,H			; CHECK LOOP COUNTER
 	OR	L
-	JR	NZ,IMM_GETDATALEN1
+	JR	NZ,IMM_GETDATALEN1	; LOOP IF NOT DONE
 	LD	A,$0C
 	CALL	IMM_WRITECTRL
 	RET
 ;
+; PUT A CHUNK OF DATA TO THE SCSI BUS.  THIS IS SPECIFICALLY FOR
+; WRITE PHASE.  IF A LENGTH IS SPECIFIED (NON-ZERO HL), THEN THE
+; DATA IS BURST WRITTEN.  IF NO LENGTH SPECIFIED, DATA IS WRITTEN AS
+; LONG AS SCSI DEVICE WANTS TO CONTINUE RECEIVING (NO OVERRUN
+; CHECK IN THIS CASE).
+;
+; READS ARE DONE AS BYTE PAIRS.  EACH LOOP READS 2 BYTES.
+;
 ; DE=BUFFER
 ; HL=LENGTH (0 FOR VARIABLE)
 ;
@@ -903,37 +957,37 @@ IMM_PUTDATA:
 	OR	L
 	JR	NZ,IMM_PUTDATALEN
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nPUTDATA:$")
 #ENDIF
 ;
 IMM_PUTDATA1:
-	PUSH	HL
-	CALL	IMM_WAITDONE
-	POP	HL
-	CP	$88
-	JR	NZ,IMM_PUTDATA2
+	PUSH	HL			; SAVE BYTE COUNTER
+	CALL	IMM_WAIT		; WAIT FOR BUS READY
+	POP	HL			; RESTORE BYTE COUNTER
+	CP	$88			; CHECK FOR WRITE PHASE
+	JR	NZ,IMM_PUTDATA2		; IF NOT, ASSUME WE ARE DONE
 	LD	A,$04
 	CALL	IMM_WRITECTRL
-	LD	A,(DE)
-	CALL	IMM_WRITEDATA
-	INC	DE
-	INC	HL
+	LD	A,(DE)			; GET NEXT BYTE TO WRITE (FIRST OF PAIR)
+	CALL	IMM_WRITEDATA		; PUT ON BUS
+	INC	DE			; BUMP TO NEXT BUF POS
+	INC	HL			; INCREMENT COUNTER
 	LD	A,$05
 	CALL	IMM_WRITECTRL
-	LD	A,(DE)
-	CALL	IMM_WRITEDATA
-	INC	DE
-	INC	HL
+	LD	A,(DE)			; GET NEXT BYTE TO WRITE (SECOND OF PAIR)
+	CALL	IMM_WRITEDATA		; PUT ON BUS
+	INC	DE			; BUMP TO NEXT BUF POS
+	INC	HL			; INCREMENT COUNTER
 	LD	A,$00
 	CALL	IMM_WRITECTRL
-	JR	IMM_PUTDATA1
+	JR	IMM_PUTDATA1		; LOOP TILL DONE
 ;
 IMM_PUTDATA2:
 	LD	A,$04
 	CALL	IMM_WRITECTRL
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXWORDHL
 	PRTS(" BYTES$")
@@ -943,7 +997,7 @@ IMM_PUTDATA2:
 ;
 IMM_PUTDATALEN:
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nPUTDLEN:$")
 	CALL	PC_SPACE
 	CALL	PRTHEXWORDHL
@@ -953,55 +1007,55 @@ IMM_PUTDATALEN:
 	LD	A,$04
 	CALL	IMM_WRITECTRL
 IMM_PUTDATALEN1:
-	LD	A,(DE)
-	CALL	IMM_WRITEDATA
-	INC	DE
-	DEC	HL
+	LD	A,(DE)			; GET NEXT BYTE (FIRST OF PAIR)
+	CALL	IMM_WRITEDATA		; PUT ON BUS
+	INC	DE			; INCREMENT BUF POS
+	DEC	HL			; DEC LOOP COUNTER
 	LD	A,$05
 	CALL	IMM_WRITECTRL
-	LD	A,(DE)
-	CALL	IMM_WRITEDATA
-	INC	DE
-	DEC	HL
+	LD	A,(DE)			; GET NEXT BYTE (SECOND OF PAIR)
+	CALL	IMM_WRITEDATA		; PUT ON BUS
+	INC	DE			; INCREMENT BUF POS
+	DEC	HL			; DEC LOOP COUNTER
 	LD	A,$00
 	CALL	IMM_WRITECTRL
-	LD	A,H
+	LD	A,H			; CHECK LOOP COUNTER
 	OR	L
-	JR	NZ,IMM_PUTDATALEN1
+	JR	NZ,IMM_PUTDATALEN1	; LOOP TILL DONE
 	LD	A,$04
 	CALL	IMM_WRITECTRL
 	RET
 ;
-;
+; READ SCSI COMMAND STATUS
 ;
 IMM_GETSTATUS:
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nSTATUS:$")
 #ENDIF
 ;
-	CALL	IMM_GETBYTE
-	LD	(IMM_CMDSTAT),A
+	CALL	IMM_GETBYTE		; GET ONE BYTE
+	LD	(IMM_CMDSTAT),A		; SAVE AS FIRST STATUS BYTE
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
-	CALL	IMM_WAITDONE
-	CP	$B8
-	RET	NZ
-	CALL	IMM_GETBYTE
-	LD	(IMM_CMDSTAT+1),A
+	CALL	IMM_WAIT		; CHECK FOR OPTIONAL SECOND BYTE
+	CP	$B8			; STILL IN STATUS PHASE?
+	RET	NZ			; IF NOT, DONE
+	CALL	IMM_GETBYTE		; ELSE, GET THE SECOND BYTE
+	LD	(IMM_CMDSTAT+1),A	; AND SAVE IT
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	CALL	PC_SPACE
 	CALL	PRTHEXBYTE
 #ENDIF
 ;
 	RET
 ;
-;
+; TERMINATE A BULD READ OPERATION
 ;
 IMM_ENDREAD:
 	LD	A,$04
@@ -1014,26 +1068,37 @@ IMM_ENDREAD:
 	CALL	IMM_WRITECTRL
 	RET
 ;
+; THIS IS THE MAIN SCSI ENGINE.  BASICALLY, IT SELECTS THE DEVICE
+; ON THE BUS, SENDS THE COMMAND, THEN PROCESSES THE RESULT.
+;
 ; HL: COMMAND BUFFER
 ; DE: TRANSFER BUFFER
 ; BC: TRANSFER LENGTH (0=VARIABLE)
 ;
 IMM_RUNCMD:
+	; THERE ARE MANY PLACES NESTED WITHIN THE ROUTINES THAT
+	; ARE CALLED HERE.  HERE WE SAVE THE STACK SO THAT WE CAN
+	; EASILY AND QUICKLY ABORT OUT OF ANY NESTED ROUTINE.
+	; SEE IMM_CMD_ERR BELOW.
 	LD	(IMM_CMDSTK),SP		; FOR ERROR ABORTS
 	LD	(IMM_DSKBUF),DE		; SAVE BUF PTR
 	LD	(IMM_XFRLEN),BC		; SAVE XFER LEN
 	PUSH	HL
-	CALL	IMM_CONNECT
-	CALL	IMM_SELECT
-	CALL	IMM_WAITBUSY
-	POP	DE
-	CALL	IMM_SENDCMD
+	CALL	IMM_CONNECT		; PARALLEL PORT BUS CONNECT
+	CALL	IMM_SELECT		; SELECT TARGET DEVICE
+	CALL	IMM_WAIT		; WAIT TILL READY
+	POP	HL
+	CALL	IMM_SENDCMD		; SEND THE COMMAND
 ;
 IMM_RUNCMD_PHASE:
-	LD	HL,50000		; LONG TIMEOUT HERE
-	CALL	IMM_WAITDONE_HL
-;
-#IF IMMTRACE >= 2)
+	; WAIT FOR THE BUS TO BE READY.  WE USE AN EXTRA LONG WAIT
+	; TIMEOUT HERE BECAUSE THIS IS WHERE WE WILL WAIT FOR LONG
+	; OPERATIONS TO COMPLETE.  IT CAN TAKE SOME TIME IF THE
+	; DEVICE HAS GONE TO SLEEP BECAUSE IT WILL NEED TO WAKE UP
+	; AND SPIN UP BEFORE PROCESSING AN I/O COMMAND.
+	CALL	IMM_LONGWAIT		; WAIT TILL READY
+;
+#IF (IMMTRACE >= 3)
 	PRTS("\r\nPHASE: $")
 	CALL	PRTHEXBYTE
 #ENDIF
@@ -1047,52 +1112,58 @@ IMM_RUNCMD_PHASE:
 	JR	IMM_CMD_IOERR
 ;
 IMM_RUNCMD_WRITE:
-	LD	DE,(IMM_DSKBUF)
+	LD	DE,(IMM_DSKBUF)		; XFER BUFFER
 	LD	HL,(IMM_XFRLEN)		; XFER LENGTH
 	CALL	IMM_PUTDATA		; SEND DATA NOW
-	JR	IMM_RUNCMD_PHASE
+	JR	IMM_RUNCMD_PHASE	; BACK TO DISPATCH
 ;
 IMM_RUNCMD_READ:
-	CALL	IMM_NEGOTIATE
-	CALL	IMM_WAITDONE
+	CALL	IMM_NEGOTIATE		; NEGOTIATE FOR READ
+	CALL	IMM_WAIT		; WAIT TILL READY
 	; CHECK FOR STATUS $98???
-	LD	DE,(IMM_DSKBUF)
+	LD	DE,(IMM_DSKBUF)		; XFER BUFFER
 	LD	HL,(IMM_XFRLEN)		; XFER LENGTH
 	CALL	IMM_GETDATA		; GET THE DATA NOW
-	CALL	IMM_ENDREAD
-	JR	IMM_RUNCMD_PHASE
+	CALL	IMM_ENDREAD		; TERMINATE THE READ
+	JR	IMM_RUNCMD_PHASE	; BACK TO DISPATCH
 ;
 IMM_RUNCMD_END:
-	CALL	IMM_NEGOTIATE
-	CALL	IMM_WAITDONE
+	CALL	IMM_NEGOTIATE		; NEGOTIATE FOR READ (STATUS)
+	CALL	IMM_WAIT		; WAIT TILL READY
 	; CHECK FOR STATUS $B8???
-	CALL	IMM_GETSTATUS
-	CALL	IMM_ENDREAD
-	CALL	IMM_DISCONNECT
+	CALL	IMM_GETSTATUS		; READ STATUS BYTES
+	CALL	IMM_ENDREAD		; TERMINATE THE READ
+	CALL	IMM_DISCONNECT		; PARALLEL PORT BUS DISCONNECT
 	XOR	A			; SIGNAL SUCCESS
 	RET
 ;
 IMM_CMD_IOERR:
-	LD	A,IMM_STIOERR
-	JR	IMM_CMD_ERR
+	LD	A,IMM_STIOERR		; ERROR VALUE TO A
+	JR	IMM_CMD_ERR		; CONTINUE
 ;
 IMM_CMD_TIMEOUT:
-	LD	A,IMM_STTO
-	JR	IMM_CMD_ERR
+	LD	A,IMM_STTO		; ERROR VALUE TO A
+	JR	IMM_CMD_ERR		; CONTINUE
 ;
 IMM_CMD_ERR:
 	LD	SP,(IMM_CMDSTK)		; UNWIND STACK
 	PUSH	AF			; SAVE STATUS
 	;CALL	IMM_RESETPULSE		; CLEAN UP THE MESS???
-	LD	DE,62
+	LD	DE,62			; DELAY AFTER RESET PULSE
 	CALL	VDELAY
-	CALL	IMM_DISCONNECT
-	LD	DE,62
+	CALL	IMM_DISCONNECT		; PARALLEL PORT BUS DISCONNECT
+	LD	DE,62			; DELAY AFTER DISCONNECT
 	CALL	VDELAY
 	POP	AF			; RECOVER STATUS
-	JP	IMM_ERR			; ERROR EXIT
-;
+	JP	IMM_ERR			; NOW DO STANDARD ERR PROCESSING
 ;
+; ERRORS SHOULD GENERALLY NOT CAUSE SCSI PROCESSING TO FAIL.  IF A
+; DEVICE ERROR (I.E., READ ERROR) OCCURS, THEN THE SCSI PROTOCOL WILL
+; PROVIDE ERROR INFORMATION.  THE STATUS RESULT OF THE SCSI COMMAND
+; WILL INDICATE IF AN ERROR OCCURRED.  ADDITIONALLY, IF THE ERROR IS
+; A CHECK CONDITION ERROR, THEN IT IS MANDATORY TO ISSUE A SENSE
+; REQUEST SCSI COMMAND TO CLEAR THE ERROR AND RETRIEVE DETAILED ERROR
+; INFO.
 ;
 IMM_CHKCMD:
 	; SCSI COMMAND COMPLETED, CHECK SCSI CMD STATUS
@@ -1114,7 +1185,7 @@ IMM_CHKCMD1:
 	JP	NZ,IMM_IOERR		; BAIL IF ERROR IN CMD
 ;
 	; REQ SENSE CMD COMPLETED
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	LD	A,16
 	LD	DE,HB_WRKBUF
 	CALL	Z,PRTHEXBUF
@@ -1126,6 +1197,7 @@ IMM_CHKCMD1:
 	JP	NZ,IMM_IOERR		; IF FAILED, GENERAL I/O ERROR
 ;
 	; RETURN RESULT BASED ON REQ SENSE DATA
+	; TODO: WE NEED TO CHECK THE SENSE KEY FIRST!!!
 	LD	A,(HB_WRKBUF+12)	; GET ADDITIONAL SENSE CODE
 	CP	$3A			; NO MEDIA?
 	JP	Z,IMM_NOMEDIA		; IF SO, RETURN NO MEDIA ERR
@@ -1149,65 +1221,73 @@ IMM_INITDEV:
 	LD	C,A			; MOVE TO C FOR I/O
 	LD	A,$82			; CONFIG A OUT, B IN, C OUT
 	OUT	(C),A			; DO IT
-	CALL	DELAY
+	CALL	DELAY			; SHORT DELAY FOR BUS SETTLE
 ;
-	CALL	IMM_DISCONNECT
-	CALL	IMM_CONNECT
-	CALL	IMM_RESETPULSE
-	LD	DE,62
+	CALL	IMM_DISCONNECT		; DISCONNECT FIRST JUST IN CASE
+	CALL	IMM_CONNECT		; NOW CONNECT TO BUS
+	CALL	IMM_RESETPULSE		; ISSUE A SCSI BUS RESET
+	LD	DE,62			; WAIT A BIT
 	CALL	VDELAY
-	CALL	IMM_DISCONNECT
-	LD	DE,62
+	CALL	IMM_DISCONNECT		; AND DISCONNECT FROM BUS
+	LD	DE,62			; WAIT A BIT MORE
 	CALL	VDELAY
 ;
-	LD	B,4
+	; INITIALLY, THE DEVICE MAY REQUIRE MULTIPLE REQUEST SENSE
+	; COMMANDS BEFORE IT WILL ACCEPT I/O COMMANDS.  THIS IS DUE
+	; TO THINGS LIKE BUS RESET NOTIFICATION, MEDIA CHANGE, ETC.
+	; HERE, WE RUN A FEW REQUEST SENSE COMMANDS.  AS SOON AS ONE
+	; INDICATES NO ERRORS, WE CAN CONTINUE.
+	LD	B,4			; TRY UP TO 4 TIMES
 IMM_INITDEV1:
-	PUSH	BC
+	PUSH	BC			; SAVE LOOP COUNTER
 ;
 	; REQUEST SENSE COMMAND
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMD
+	LD	DE,HB_WRKBUF		; BUFFER FOR SENSE DATA
+	LD	BC,0			; READ WHATEVER IS SENT
+	LD	HL,IMM_CMD_SENSE	; POINT TO CMD BUFFER
+	CALL	IMM_RUNCMD		; RUN THE SCSI ENGINE
 	JR	NZ,IMM_INITDEV2		; CMD PROC ERROR
 ;
 	; CHECK CMD STATUS
 	LD	A,(IMM_CMDSTAT)		; GET STATUS BYTE
 	OR	A			; SET FLAGS
-	JR	NZ,IMM_INITDEV2		; BAD CMD STATUS
+	JR	NZ,IMM_INITDEV2		; IF ERROR, LOOP
 ;
-#IF IMMTRACE >= 2)
+#IF (IMMTRACE >= 3)
 	LD	A,16
 	LD	DE,HB_WRKBUF
 	CALL	PRTHEXBUF
 #ENDIF
 ;
 	; CHECK SENSE KEY
-	LD	A,(HB_WRKBUF + 2)
-	OR	A
+	LD	A,(HB_WRKBUF + 2)	; GET SENSE KEY
+	OR	A			; SET FLAGS
 ;
 IMM_INITDEV2:
-	POP	BC
+	POP	BC			; RESTORE LOOP COUNTER
 	JR	Z,IMM_INITDEV3		; IF NO ERROR, MOVE ON
 	DJNZ	IMM_INITDEV1		; TRY UNTIL COUNTER EXHAUSTED
-	JP	IMM_IOERR		; HANDLE ERROR
+	JP	IMM_IOERR		; BAIL OUT WITH ERROR
 ;
 IMM_INITDEV3:
 	; READ & RECORD DEVICE CAPACITY
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_RDCAP
-	CALL	IMM_RUNCMD
-	CALL	Z,IMM_CHKCMD
-	RET	NZ			; MEDIA PROBLEM
-;
-#IF IMMTRACE >= 2)
+	LD	DE,HB_WRKBUF		; BUFFER TO CAPACITY RESPONSE
+	LD	BC,0			; READ WHATEVER IS SENT
+	LD	HL,IMM_CMD_RDCAP	; POINT TO READ CAPACITY CMD
+	CALL	IMM_RUNCMD		; RUN THE SCSI ENGINE
+	CALL	Z,IMM_CHKCMD		; CHECK AND RECORD AND ERRORS
+	RET	NZ			; BAIL ON ON ERROR
+;
+#IF (IMMTRACE >= 3)
 	LD	A,8
 	LD	DE,HB_WRKBUF
 	CALL	PRTHEXBUF
 #ENDIF
 ;
-	; INCREMENT, BIG->LITTLE ENDIAN, SAVE
+	; CAPACITY IS RETURNED IN A 4 BYTE, BIG ENDIAN FIELD AND
+	; INDICATES THE LAST LBA VALUE.  WE NEED TO CONVERT THIS TO
+	; LITTLE ENDIAN AND INCREMENT THE VALUE TO MAKE IT A CAPACITY
+	; COUNT INSTEAD OF A LAST LBA VALUE.
 	LD	A,IMM_MEDCAP		; OFFSET IN CFG FOR CAPACITY
 	CALL	LDHLIYA			; POINTER TO HL
 	PUSH	HL			; SAVE IT
@@ -1430,10 +1510,13 @@ IMM_TYPE_MAP:
 IMM_STR_NONE	.DB	"<NOT PRESENT>$"
 IMM_STR_MG014	.DB	"MG014$"
 ;
-; SCSI COMMAND TEMPLATES
+; SCSI COMMAND TEMPLATES (LENGTH PREFIXED)
 ;
+		.DB	6
 IMM_CMD_RW	.DB	$00, $00, $00, $00, $01, $00	; READ/WRITE SECTOR
+		.DB	6
 IMM_CMD_SENSE	.DB	$03, $00, $00, $00, $FF, $00	; REQUEST SENSE DATA
+		.DB	10
 IMM_CMD_RDCAP	.DB	$25, $00, $00, $00, $00, $00, $00, $00, $00, $00 ; READ CAPACITY
 ;
 ; IMM DEVICE CONFIGURATION TABLE
diff --git a/Source/HBIOS/lpt.asm b/Source/HBIOS/lpt.asm
index 7075a7e1..1ee0aab6 100644
--- a/Source/HBIOS/lpt.asm
+++ b/Source/HBIOS/lpt.asm
@@ -372,7 +372,7 @@ LPT_PRTCFG:
 	CALL	PRTHEXBYTE		; PRINT BASE PORT
 
 	; PRINT THE LPT TYPE
-	CALL	PC_SPACE		; FORMATTING
+	PRTS(": MODE=$")		; FORMATTING
 	LD	A,(IY+1)		; GET LPT TYPE BYTE
 	RLCA				; MAKE IT A WORD OFFSET
 	LD	HL,LPT_TYPE_MAP		; POINT HL TO TYPE MAP TABLE
diff --git a/Source/HBIOS/ppa.asm b/Source/HBIOS/ppa.asm
index 529b81b3..e74077de 100644
--- a/Source/HBIOS/ppa.asm
+++ b/Source/HBIOS/ppa.asm
@@ -12,7 +12,8 @@
 ; CREATED BY WAYNE WARTHEN FOR ROMWBW HBIOS.
 ; MUCH OF THE CODE IS DERIVED FROM FUZIX (ALAN COX).
 ;
-; 5/19/2023 WBW - INITIAL RELEASE
+; 5/23/2023 WBW - INITIAL RELEASE
+; 5/26/3023 WBW - CLEAN UP, LED ACTIVITY
 ;
 ;=============================================================================
 ;
@@ -43,20 +44,32 @@
 ;
 ; TODO:
 ;
+; - CLEAN UP WAIT LOOP STUFF
+;
+; - OPTIMIZE READ/WRITE LOOPS
+;
 ; NOTES:
 ;
-;;;;
-;;;; COMMAND BYTES
-;;;;
-;;;PPA_CPPA_NOP		.EQU	$00
-;;;PPA_CPPA_DEVRES		.EQU	$08
-;;;PPA_CPPA_RECAL		.EQU	$10
-;;;PPA_CPPA_READ		.EQU	$20
-;;;PPA_CPPA_WRITE		.EQU	$30
-;;;PPA_CPPA_DEVDIAG	.EQU	$90
-;;;PPA_CPPA_IDPKTDEV	.EQU	$A1
-;;;PPA_CPPA_IDDEV		.EQU	$EC
-;;;PPA_CPPA_SETFEAT	.EQU	$EF
+; - THIS DRIVER IS FOR THE ZIP DRIVE PPA INTERFACE.  IT WILL SIMPLY
+;   FAIL TO EVEN RECOGNIZE A ZIP DRIVE WITH THE OLDER PPA INTERFACE.
+;   THERE DOES NOT SEEM TO BE A WAY TO VISUALLY DETERMINE IF A ZIP
+;   DRIVE IS PPA OR PPA.  SIGH.
+;
+; - THERE ARE SOME HARD CODED TIMEOUT LOOPS IN THE CODE.  THEY ARE
+;   WORKING OK ON A 7 MHZ Z80.  THEY ARE LIKELY TO NEED TWEAKING ON
+;   FASTER CPUS.
+;
+; - THIS DRIVER OPERATES PURELY IN NIBBLE MODE.  I SUSPECT IT IS
+;   POSSIBLE TO USE FULL BYTE MODE (PS2 STYLE), BUT I HAVE NOT
+;   ATTEMPTED IT.
+;
+; - RELATIVE TO ABOVE, THIS BEAST IS SLOW.  IN ADDITION TO THE
+;   NIBBLE MODE READS, THE MG014 ASSIGNS SIGNALS DIFFERENTLY THAN
+;   THE STANDARD IBM PARALLEL PORT WHICH NECESSITATES A BUNCH OF EXTRA
+;   BIT FIDDLING ON EVERY READ.
+;
+; - SOME OF THE DATA TRANSFERS HAVE NO BUFFER OVERRUN CHECKS.  IT IS
+;   ASSUMED SCSI DEVICES WILL SEND/REQUEST THE EXPECTED NUMBER OF BYTES.
 ;
 ; PPA PORT OFFSETS
 ;
@@ -65,6 +78,11 @@ PPA_IOSTAT	.EQU	1		; PORT B, STATUS, IN
 PPA_IOCTRL	.EQU	2		; PORT C, CTRL, OUT
 PPA_IOSETUP	.EQU	3		; PPI SETUP
 ;
+; SCSI UNIT IDS
+;
+PPA_SELF	.EQU	7
+PPA_TGT		.EQU	6
+;
 ; PPA DEVICE STATUS
 ;
 PPA_STOK	.EQU	0
@@ -103,17 +121,8 @@ PPA_INIT1:
 	RET				; AND RETURN
 ;
 PPA_INIT2:
-	; CHECK FOR HARDWARE PRESENCE
-	CALL	PPA_DETECT		; PROBE FOR INTERFACE
-	JP	NZ,PPA_INIT6		; SKIP CFG ENTRY
-;
-	; UPDATE DRIVER RELATIVE UNIT NUMBER IN CONFIG TABLE
-	LD	A,(PPA_DEVNUM)		; GET NEXT UNIT NUM TO ASSIGN
-	LD	(IY+PPA_DEV),A		; UPDATE IT
-	INC	A			; BUMP TO NEXT UNIT NUM TO ASSIGN
-	LD	(PPA_DEVNUM),A		; SAVE IT
-;
-	CALL	PPA_PRTPREFIX		; PRINT DEVICE PREFIX
+	CALL	NEWLINE			; FORMATTING
+	PRTS("PPA:$")			; DRIVER LABEL
 ;
 	PRTS(" IO=0x$")			; LABEL FOR IO ADDRESS
 	LD	A,(IY+PPA_IOBASE)	; GET IO BASE ADDRES
@@ -130,15 +139,32 @@ PPA_INIT2:
 	LD	DE,PPA_STR_MODE_UNK	; MODE LABEL
 PPA_INIT3:
 	CALL	WRITESTR		; DISPLAY MODE
+;
+	; CHECK FOR HARDWARE PRESENCE
+	CALL	PPA_DETECT		; PROBE FOR INTERFACE
+	JR	Z,PPA_INIT4		; IF FOUND, CONTINUE
+	CALL	PC_SPACE		; FORMATTING
+	LD	DE,PPA_STR_NOHW		; NO PPA MESSAGE
+	CALL	WRITESTR		; DISPLAY IT
+	JR	PPA_INIT6		; SKIP CFG ENTRY
 ;
 PPA_INIT4:
-	CALL	PPA_RESET		; RESET THE INTERFACE
+	; UPDATE DRIVER RELATIVE UNIT NUMBER IN CONFIG TABLE
+	LD	A,(PPA_DEVNUM)		; GET NEXT UNIT NUM TO ASSIGN
+	LD	(IY+PPA_DEV),A		; UPDATE IT
+	INC	A			; BUMP TO NEXT UNIT NUM TO ASSIGN
+	LD	(PPA_DEVNUM),A		; SAVE IT
 ;
 	; ADD UNIT TO GLOBAL DISK UNIT TABLE
 	LD	BC,PPA_FNTBL		; BC := FUNC TABLE ADR
 	PUSH	IY			; CFG ENTRY POINTER
 	POP	DE			; COPY TO DE
 	CALL	DIO_ADDENT		; ADD ENTRY TO GLOBAL DISK DEV TABLE
+;
+	CALL	PPA_RESET		; RESET/INIT THE INTERFACE
+;
+	; START PRINTING DEVICE INFO
+	CALL	PPA_PRTPREFIX		; PRINT DEVICE PREFIX
 ;
 	; CHECK FOR BAD STATUS
 	LD	A,(IY+PPA_STAT)		; GET STATUS
@@ -175,9 +201,59 @@ PPA_INIT6:
 ; ON RETURN, ZF SET INDICATES HARDWARE FOUND
 ;
 PPA_DETECT:
+	; INITIALIZE 8255
+	LD	A,(IY+PPA_IOBASE)	; BASE PORT
+	ADD	A,PPA_IOSETUP		; BUMP TO SETUP PORT
+	LD	C,A			; MOVE TO C FOR I/O
+	LD	A,$82			; CONFIG A OUT, B IN, C OUT
+	OUT	(C),A			; DO IT
+	CALL	DELAY			; BRIEF DELAY FOR GOOD MEASURE
+;
+	LD	A,$AA
+	CALL	PPA_WRITEDATA
+	CALL	PPA_DISCONNECT
+	CALL	PPA_CONNECT
+	LD	A,$06
+	CALL	PPA_WRITECTRL
+	CALL	PPA_READSTATUS
+;
+	CALL	PC_SPACE
+	CALL	PRTHEXBYTE
+;
+	AND	$F0
+	CP	$F0
+	JR	NZ,PPA_DETECT_FAIL
+	LD	A,$04
+	CALL	PPA_WRITECTRL
+	CALL	PPA_READSTATUS
+;
+	CALL	PC_SPACE
+	CALL	PRTHEXBYTE
+;
+	AND	$F0
+	CP	$80
+	JR	NZ,PPA_DETECT_FAIL
+	LD	A,$AA
+	CALL	PPA_WRITEDATA
+	LD	A,$0C
+	CALL	PPA_WRITECTRL
+	CALL	PPA_CONNECT
+	LD	A,$40
+	CALL	PPA_WRITEDATA
+	LD	A,$08
+	CALL	PPA_WRITECTRL
+	LD	A,$0C
+	CALL	PPA_WRITECTRL
+	CALL	PPA_DISCONNECT
+;
 	XOR	A			; SIGNAL SUCCESS
 	RET				; AND RETURN
 ;
+PPA_DETECT_FAIL:
+	OR	$FF			; SIGNAL FAILURE
+	RET	NZ
+
+;
 ;=============================================================================
 ; DRIVER FUNCTION TABLE
 ;=============================================================================
@@ -208,12 +284,64 @@ PPA_DEFMED:
 ;
 ;
 PPA_READ:
-	JP	PPA_STNOTSUP		; NOT SUPPORTED
+	CALL	HB_DSKREAD		; HOOK DISK READ CONTROLLER
+	LD	A,SCSI_CMD_READ		; SETUP SCSI READ
+	LD	(PPA_CMD_RW),A		; AND SAVE IT IN SCSI CMD
+	JP	PPA_IO			; DO THE I/O
 ;
 ;
 ;
 PPA_WRITE:
-	JP	PPA_STNOTSUP		; NOT SUPPORTED
+	CALL	HB_DSKREAD		; HOOK DISK WRITE CONTROLLER
+	LD	A,SCSI_CMD_WRITE	; SETUP SCSI WRITE
+	LD	(PPA_CMD_RW),A		; AND SAVE IT IN SCSI CMD
+	JP	PPA_IO			; DO THE I/O
+;
+;
+;
+PPA_IO:
+	LD	(PPA_DSKBUF),HL		; SAVE DISK BUFFER ADDRESS
+	CALL	PPA_CHKERR		; CHECK FOR ERR STATUS AND RESET IF SO
+	JR	NZ,PPA_IO3		; BAIL OUT ON ERROR
+;
+	; SETUP LBA
+	; 3 BYTES, LITTLE ENDIAN -> BIG ENDIAN
+	LD	HL,PPA_CMD_RW+1		; START OF LBA FIELD IN CDB (MSB)
+	LD	A,(IY+PPA_LBA+2)	; THIRD BYTE OF LBA FIELD IN CFG (MSB)
+	LD	(HL),A
+	INC	HL
+	LD	A,(IY+PPA_LBA+1)
+	LD	(HL),A
+	INC	HL
+	LD	A,(IY+PPA_LBA+0)
+	LD	(HL),A
+	INC	HL
+;
+	; DO SCSI IO
+	LD	DE,(PPA_DSKBUF)		; DISK BUFFER TO DE
+	LD	BC,512			; ONE SECTOR, 512 BYTES
+	LD	HL,PPA_CMD_RW		; POINT TO READ/WRITE CMD TEMPLATE
+	CALL	PPA_RUNCMD		; RUN THE SCSI ENGINE
+	CALL	Z,PPA_CHKCMD		; IF EXIT OK, CHECK SCSI RESULTS
+	JR	NZ,PPA_IO2		; IF ERROR, SKIP INCREMENT
+	; INCREMENT LBA
+	LD	A,PPA_LBA		; LBA OFFSET
+	CALL	LDHLIYA			; HL := IY + A, REG A TRASHED
+	CALL	INC32HL			; INCREMENT THE VALUE
+	; INCREMENT DMA
+	LD	HL,IDE_DSKBUF+1		; POINT TO MSB OF BUFFER ADR
+	INC	(HL)			; BUMP DMA BY
+	INC	(HL)			; ... 512 BYTES
+	XOR	A			; SIGNAL SUCCESS
+;
+PPA_IO2:
+PPA_IO3:
+	LD	HL,(PPA_DSKBUF)		; CURRENT DMA TO HL
+	OR	A			; SET FLAGS BASED ON RETURN CODE
+	RET	Z			; RETURN IF SUCCESS
+	LD	A,ERR_IO		; SIGNAL IO ERROR
+	OR	A			; SET FLAGS
+	RET				; AND DONE
 ;
 ;
 ;
@@ -225,6 +353,11 @@ PPA_STATUS:
 ;
 ;
 ;
+PPA_RESET:
+	JP	PPA_INITDEV		; JUST (RE)INIT DEVICE
+;
+;
+;
 PPA_DEVICE:
 	LD	D,DIODEV_PPA		; D := DEVICE TYPE
 	LD	E,(IY+PPA_DEV)		; E := PHYSICAL DEVICE NUMBER
@@ -236,13 +369,12 @@ PPA_DEVICE:
 ;
 ; PPA_GETMED
 ;
-PPA_MEDIA:	
+PPA_MEDIA:
 	LD	A,E			; GET FLAGS
 	OR	A			; SET FLAGS
 	JR	Z,PPA_MEDIA1		; JUST REPORT CURRENT STATUS AND MEDIA
 ;
-	;CALL	PPA_RESET		; RESET PPA INTERFACE
-	CALL	PPA_INITUNIT		; RE-INITIALIZE UNIT
+	CALL	PPA_RESET		; RESET INCLUDES MEDIA CHECK
 ;
 PPA_MEDIA1:
 	LD	A,(IY+PPA_STAT)		; GET STATUS
@@ -297,11 +429,6 @@ PPA_GEOM:
 ; FUNCTION SUPPORT ROUTINES
 ;=============================================================================
 ;
-PPA_SELF	.EQU	7
-PPA_TGT		.EQU	6
-;
-IMM_TGT		.EQU	6
-;
 ;
 ;
 PPA_DELAY:
@@ -315,79 +442,90 @@ PPA_DELAY:
 ;
 ;
 ;
+PPA_WAITDONE:
+	LD	HL,0			; TIMEOUT COUNTER
+PPA_WAITDONE1:
+	CALL	PPA_READSTATUS
+	AND	$F0
+	BIT	7,A
+	RET	NZ
+	DEC	HL
+	LD	A,H
+	OR	L
+	JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
+	JR	PPA_WAITDONE1
+;
+; OUTPUT BYTE IN A TO THE DATA PORT
+;
 PPA_WRITEDATA:
-	;PRTS(" D-$")
-	;CALL	PRTHEXBYTE
-
-	LD	C,(IY+PPA_IOBASE)
-	OUT	(C),A
-	CALL	PPA_DELAY
-	RET
+	LD	C,(IY+PPA_IOBASE)	; DATA PORT IS AT IOBASE
+	OUT	(C),A			; WRITE THE BYTE
+	;CALL	DELAY			; IS THIS NEEDED???
+	RET				; DONE
 ;
 ;
 ;
 PPA_WRITECTRL:
-	;PRTS(" C-$")
-	;CALL	PRTHEXBYTE
-
-	XOR	$0B
-
-	;PRTS(">$")
-	;CALL	PRTHEXBYTE
-
-	LD	C,(IY+PPA_IOBASE)
+	; IBM PC INVERTS ALL BUT C2 ON THE BUS, MG014 DOES NOT.
+	; BELOW TRANSLATES FROM IBM -> MG014.	IT ALSO INVERTS THE
+	; MG014 LED SIMPLY TO MAKE IT EASY TO KEEP LED ON DURING
+	; ALL ACTIVITY.
+	XOR	$0B | $80		; HIGH BIT IS MG014 LED
+	LD	C,(IY+PPA_IOBASE)	; GET BASE IO ADDRESS
+	INC	C			; BUMP TO CONTROL PORT
 	INC	C
-	INC	C
-	OUT	(C),A
-	CALL	PPA_DELAY
-	RET
+	OUT	(C),A			; WRITE TO CONTROL PORT
+	;CALL	DELAY			; IS THIS NEEDED?
+	RET				; DONE
 ;
+; READ THE PARALLEL PORT INPUT LINES (STATUS) AND MAP SIGNALS FROM
+; MG014 TO IBM STANDARD.  NOTE POLARITY CHANGE REQUIRED FOR BUSY.
 ;
+; 	MG014		IBM PC
+;	--------	--------
+;	0: /ACK		6: /ACK
+;	1: BUSY		7: /BUSY
+;	2: POUT		5: POUT
+;	3: SEL		4: SEL
+;	4: /ERR		3: /ERR
 ;
 PPA_READSTATUS:
-	LD	C,(IY+PPA_IOBASE)
-	INC	C
-	IN	A,(C)
-	
-	;PRTS(" I-$")
-	;CALL	PRTHEXBYTE
-	
+	LD	C,(IY+PPA_IOBASE)	; IOBASE TO C
+	INC	C			; BUMP TO STATUS PORT
+	IN	A,(C)			; READ IT
 	LD	C,0			; INIT RESULT
-;	
-	BIT	0,A			; ACK = $01
+;
+	; SHUFFLE BITS
+	BIT	0,A			; 0: /ACK
 	JR	Z,PPA_READSTATUS1
-	SET	6,C			; $40
+	SET	6,C			; 6: /ACK
 ;
 PPA_READSTATUS1:
-;	
-	BIT	1,A			; BUSY = $02
-	JR	NZ,PPA_READSTATUS2
-	SET	7,C			; $80
+;
+	BIT	1,A			; 1: BUSY
+	JR	NZ,PPA_READSTATUS2	; POLARITY CHANGE!
+	SET	7,C			; 7: /BUSY
 ;
 PPA_READSTATUS2:
-;	
-	BIT	2,A			; PAPER = $04
+;
+	BIT	2,A			; 2: POUT
 	JR	Z,PPA_READSTATUS3
-	SET	5,C			; $20
+	SET	5,C			; 5: POUT
 ;
 PPA_READSTATUS3:
-;	
-	BIT	3,A			; SELECT = $08
+;
+	BIT	3,A			; 3: SEL
 	JR	Z,PPA_READSTATUS4
-	SET	4,C			; $10
+	SET	4,C			; 4: SEL
 ;
 PPA_READSTATUS4:
-;	
-	BIT	4,A			; FAULT = $10
+;
+	BIT	4,A			; 4: /ERR
 	JR	Z,PPA_READSTATUS5
-	SET	3,C			; $08
+	SET	3,C			; 3: /ERR
 ;
 PPA_READSTATUS5:
-	LD	A,C
-	
-	;PRTS(">$")
-	;CALL	PRTHEXBYTE
-	
+	LD	A,C			; RESULT TO A
 	RET
 ;
 ;
@@ -423,7 +561,6 @@ PPA_CPULSE:
 ;
 ;
 PPA_CONNECT:
-	CALL	NEWLINE
 	LD	A,$00
 	CALL	PPA_CPULSE
 	LD	A,$3C
@@ -436,108 +573,7 @@ PPA_CONNECT:
 ;
 ;
 ;
-IMM_CPP:
-	;CALL	NEWLINE
-	PUSH	AF
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$AA
-	CALL	PPA_WRITEDATA
-	LD	A,$55
-	CALL	PPA_WRITEDATA
-	LD	A,$00
-	CALL	PPA_WRITEDATA
-	LD	A,$FF
-	CALL	PPA_WRITEDATA
-	CALL	PPA_READSTATUS
-	AND	$B8
-	LD	(IMM_S1),A
-	LD	A,$87
-	CALL	PPA_WRITEDATA
-	CALL	PPA_READSTATUS
-	AND	$B8
-	LD	(IMM_S2),A
-	LD	A,$78
-	CALL	PPA_WRITEDATA
-	CALL	PPA_READSTATUS
-	AND	$38
-	LD	(IMM_S3),A
-	POP	AF
-	CALL	PPA_WRITEDATA
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$0D
-	CALL	PPA_WRITECTRL
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$FF
-	CALL	PPA_WRITEDATA
-
-	; CONNECT: S1=$B8 S2=$18 S3=$30
-	; DISCONNECT: S1=$B8 S2=$18 S3=$38
-
-	PRTS("\r\nCPP: S1=$")
-	LD	A,(IMM_S1)
-	CALL	PRTHEXBYTE
-	PRTS(" S2=$")
-	LD	A,(IMM_S2)
-	CALL	PRTHEXBYTE
-	PRTS(" S3=$")
-	LD	A,(IMM_S3)
-	CALL	PRTHEXBYTE
-
-	XOR	A		; ASSUME SUCCESS FOR NOW
-	RET
-;
-IMM_S1	.DB	0
-IMM_S2	.DB	0
-IMM_S3	.DB	0
-;
-;
-;
-IMM_CONNECT:
-	LD	A,$E0
-	CALL	IMM_CPP
-	LD	A,$30
-	CALL	IMM_CPP
-	LD	A,$E0
-	CALL	IMM_CPP
-	RET
-;
-;
-;
-IMM_DISCONNECT:
-	LD	A,$30
-	CALL	IMM_CPP
-	RET
-;
-;
-;
-IMM_RESETPULSE:
-	;CALL	NEWLINE
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$40
-	CALL	PPA_WRITEDATA
-	CALL	DELAY
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$0D
-	CALL	PPA_WRITECTRL
-	CALL	DELAY
-	CALL	DELAY
-	CALL	DELAY
-	CALL	DELAY
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	RET
-;
-;
-;
 PPA_DISCONNECT:
-	;CALL	NEWLINE
 	LD	A,$00
 	CALL	PPA_DPULSE
 	LD	A,$3C
@@ -548,6 +584,7 @@ PPA_DISCONNECT:
 	CALL	PPA_DPULSE
 	RET
 ;
+; SCSI SELECT PROCESS
 ;
 ;
 PPA_SELECT:
@@ -574,700 +611,95 @@ PPA_SELECT1:
 	RET	Z			; TIMEOUT
 	JR	PPA_SELECT1
 ;
+; SEND SCSI CMD BYTE STRING.  AT ENTRY, HL POINTS TO START OF
+; COMMAND BYTES.  THE LENGTH OF THE COMMAND STRING MUST PRECEED
+; THE COMMAND BYTES (HL - 1).
 ;
+; NOTE THAT DATA IS SENT AS BYTE PAIRS!  EACH LOOP SENDS 2 BYTES.
+; DATA OUTPOUT IS BURSTED (NO CHECK FOR BUSY).  SEEMS TO WORK FINE.
 ;
-IMM_SELECT:
-	PRTS("\r\nSELECT: $")
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
+PPA_SENDCMD:
+	JP	PPA_ERR			; NOW DO STANDARD ERR PROCESSING
 ;
-	LD	HL,500			; TIMEOUT COUNTER
+; THIS IS THE MAIN SCSI ENGINE.  BASICALLY, IT SELECTS THE DEVICE
+; ON THE BUS, SENDS THE COMMAND, THEN PROCESSES THE RESULT.
 ;
-IMM_SELECT1:
-	CALL	PPA_READSTATUS
-	AND	$08
-	JR	Z,IMM_SELECT2		; IF CLEAR, MOVE ON
-	DEC	HL
-	LD	A,H
-	OR	L
-	JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
-	JR	IMM_SELECT1
+; HL: COMMAND BUFFER
+; DE: TRANSFER BUFFER
+; BC: TRANSFER LENGTH (0=VARIABLE)
 ;
-IMM_SELECT2:
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$80 | (1 << IMM_TGT)
-	CALL	PPA_WRITEDATA
-	CALL	DELAY
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-
-	CALL	PPA_READSTATUS
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-
-	LD	A,$0D
-	CALL	PPA_WRITECTRL
-
-	CALL	PPA_READSTATUS
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
+PPA_RUNCMD:
+	JP	PPA_ERR			; NOW DO STANDARD ERR PROCESSING
 ;
-	LD	HL,500			; TIMEOUT COUNTER
+; ERRORS SHOULD GENERALLY NOT CAUSE SCSI PROCESSING TO FAIL.  IF A
+; DEVICE ERROR (I.E., READ ERROR) OCCURS, THEN THE SCSI PROTOCOL WILL
+; PROVIDE ERROR INFORMATION.  THE STATUS RESULT OF THE SCSI COMMAND
+; WILL INDICATE IF AN ERROR OCCURRED.  ADDITIONALLY, IF THE ERROR IS
+; A CHECK CONDITION ERROR, THEN IT IS MANDATORY TO ISSUE A SENSE
+; REQUEST SCSI COMMAND TO CLEAR THE ERROR AND RETRIEVE DETAILED ERROR
+; INFO.
 ;
-IMM_SELECT3:
-	CALL	PPA_READSTATUS
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	AND	$08
-	JR	NZ,IMM_SELECT4		; IF CLEAR, MOVE ON
-	DEC	HL
-	LD	A,H
-	OR	L
-	JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
-	JR	IMM_SELECT3
+PPA_CHKCMD:
+	; SCSI COMMAND COMPLETED, CHECK SCSI CMD STATUS
+	LD	A,(PPA_CMDSTAT)		; GET STATUS BYTE
+	OR	A			; SET FLAGS
+	RET	Z			; IF ZERO, ALL GOOD, DONE
+;
+	; DO WE HAVE A CHECK CONDITION?
+	CP	2			; CHECK CONDITION RESULT?
+	JR	Z,PPA_CHKCMD1		; IF SO, REQUEST SENSE
+	JP	PPA_IOERR		; ELSE, GENERAL I/O ERROR
+;
+PPA_CHKCMD1:
+	; USE REQUEST SENSE CMD TO GET ERROR DETAILS
+	LD	DE,HB_WRKBUF		; PUT DATA IN WORK BUF
+	LD	BC,0			; VARIABLE LENGTH REQUEST
+	LD	HL,PPA_CMD_SENSE	; REQUEST SENSE CMD
+	CALL	PPA_RUNCMD		; DO IT
+	JP	NZ,PPA_IOERR		; BAIL IF ERROR IN CMD
+;
+	; REQ SENSE CMD COMPLETED
+#IF (PPATRACE >= 3)
+	LD	A,16
+	LD	DE,HB_WRKBUF
+	CALL	Z,PRTHEXBUF
+#ENDIF
 ;
-IMM_SELECT4:
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
+	; CHECK SCSI CMD STATUS
+	LD	A,(PPA_CMDSTAT)		; GET STATUS BYTE
+	OR	A			; SET FLAGS
+	JP	NZ,PPA_IOERR		; IF FAILED, GENERAL I/O ERROR
 ;
-	XOR	A
-	RET
+	; RETURN RESULT BASED ON REQ SENSE DATA
+	; TODO: WE NEED TO CHECK THE SENSE KEY FIRST!!!
+	LD	A,(HB_WRKBUF+12)	; GET ADDITIONAL SENSE CODE
+	CP	$3A			; NO MEDIA?
+	JP	Z,PPA_NOMEDIA		; IF SO, RETURN NO MEDIA ERR
+	JP	PPA_IOERR		; ELSE GENERAL I/O ERR
 ;
+; CHECK CURRENT DEVICE FOR ERROR STATUS AND ATTEMPT TO RECOVER
+; VIA RESET IF DEVICE IS IN ERROR.
 ;
+PPA_CHKERR:
+	LD	A,(IY+PPA_STAT)		; GET STATUS
+	OR	A			; SET FLAGS
+	CALL	NZ,PPA_RESET		; IF ERROR STATUS, RESET BUS
+	RET
 ;
-IMM_SENDCMD:
-	; TODO: USE PUTDATA ROUTINE???
-	; TODO: CHECK BUSY???
-	PRTS("\r\nSENDCMD:$")
-	LD	A,$04
-	CALL	PPA_WRITECTRL
+; (RE)INITIALIZE DEVICE
 ;
-	LD	HL,IMM_CMD
-	LD	B,6
+PPA_INITDEV:
+	; INITIALIZE 8255
+	LD	A,(IY+PPA_IOBASE)	; BASE PORT
+	ADD	A,PPA_IOSETUP		; BUMP TO SETUP PORT
+	LD	C,A			; MOVE TO C FOR I/O
+	LD	A,$82			; CONFIG A OUT, B IN, C OUT
+	OUT	(C),A			; DO IT
+	CALL	DELAY			; SHORT DELAY FOR BUS SETTLE
 ;
-IMM_SENDCMD1:
-	LD	A,(HL)
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	CALL	PPA_WRITEDATA
-	INC	HL
-	DEC	B
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	LD	A,(HL)
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	CALL	PPA_WRITEDATA
-	INC	HL
-	LD	A,$00
-	CALL	PPA_WRITECTRL
-	DJNZ	IMM_SENDCMD1
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-;
-	CALL	PPA_READSTATUS
-	CALL	PC_SPACE
-	CALL	PC_GT
-	CALL	PRTHEXBYTE
-	RET
-;
-;
-;
-IMM_WAITBUSY:
-	LD	HL,500			; NORMAL TIMEOUT COUNTER
-;
-IMM_WAITBUSY_HL:			; VARIABLE TIMEOUT ENTRY
-	;PRTS("\r\nWAITB: $")
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-;
-IMM_WAITBUSY2:
-	CALL	PPA_READSTATUS
-	BIT	7,A
-	RET	NZ			; IF SET, MOVE ON
-	DEC	HL
-	LD	A,H
-	OR	L
-	JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
-	JR	IMM_WAITBUSY2
-;
-;
-;
-IMM_WAITDONE:
-	LD	HL,500			; NORMAL TIMEOUT COUNTER
-;
-IMM_WAITDONE_HL:			; VARIABLE TIMEOUT ENTRY
-	CALL	IMM_WAITBUSY_HL
-	AND	$B8
-	PUSH	AF
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	POP	AF
-	RET
-;
-;
-;
-IMM_NEGOTIATE:
-	; TODO: REVIEW TIMING DELAYS!!!
-	PRTS("\r\nNEGO: $")
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	CALL	DELAY
-	LD	A,$00
-	CALL	PPA_WRITEDATA
-	CALL	DELAY
-	CALL	DELAY
-	CALL	DELAY
-	CALL	DELAY
-	LD	A,$06
-	CALL	PPA_WRITECTRL
-	CALL	DELAY
-	CALL	PPA_READSTATUS
-	PUSH	AF			; SAVE RESULT
-	CALL	DELAY
-	LD	A,$07
-	CALL	PPA_WRITECTRL
-	CALL	DELAY
-	LD	A,$06
-	CALL	PPA_WRITECTRL
-;
-	POP	AF
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	AND	$20
-	CALL	PC_SPACE
-	CALL	PC_GT
-	CALL	PRTHEXBYTE
-	CP	$20
-	JP	NZ,IMM_CMD_IOERR
-	RET
-;
-;
-;
-PPA_WAITDONE:
-	LD	HL,0			; TIMEOUT COUNTER
-PPA_WAITDONE1:
-	CALL	PPA_READSTATUS
-	AND	$F0
-	BIT	7,A
-	RET	NZ
-	DEC	HL
-	LD	A,H
-	OR	L
-	JP	Z,IMM_CMD_TIMEOUT	; TIMEOUT
-	JR	PPA_WAITDONE1
-;
-;
-;
-IMM_GETBYTE:
-	CALL	IMM_WAITBUSY
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$06
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	RRCA
-	RRCA
-	RRCA
-	RRCA
-	PUSH 	AF
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	POP	HL
-	OR	H
-	PUSH	AF
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	POP	AF
-	RET
-;
-; DE=BUFFER
-; HL=LENGTH (0 FOR VARIABLE)
-;
-IMM_GETDATA:
-	LD	A,H
-	OR	L
-	JR	NZ,IMM_GETDATALEN
-	PRTS("\r\nGETDATA:$")
-IMM_GETDATA1:
-	PUSH	HL
-	CALL	IMM_WAITDONE
-	POP	HL
-	CP	$98
-	JR	NZ,IMM_GETDATA2
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$06
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	RRCA
-	RRCA
-	RRCA
-	RRCA
-	PUSH 	AF
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	POP	BC
-	OR	B
-	LD	(DE),A
-	INC	DE
-	INC	HL
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	JR	IMM_GETDATA1
-;
-IMM_GETDATA2:
-	CALL	PC_SPACE
-	CALL	PRTHEXWORDHL
-	PRTS(" BYTES$")
-	RET
-;
-IMM_GETDATALEN:
-	PRTS("\r\nGETDLEN:$")
-	CALL	PC_SPACE
-	CALL	PRTHEXWORDHL
-	PRTS(" BYTES$")
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-IMM_GETDATALEN1:
-	LD	A,$06
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	RRCA
-	RRCA
-	RRCA
-	RRCA
-	PUSH 	AF
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	POP	BC
-	OR	B
-	LD	(DE),A
-	INC	DE
-	DEC	HL
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,H
-	OR	L
-	JR	NZ,IMM_GETDATALEN1
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	RET
-;
-; DE=BUFFER
-; HL=LENGTH (0 FOR VARIABLE)
-;
-IMM_PUTDATA:
-	LD	A,H
-	OR	L
-	JR	NZ,IMM_PUTDATALEN
-	PRTS("\r\nPUTDATA:$")
-IMM_PUTDATA1:
-	PUSH	HL
-	CALL	IMM_WAITDONE
-	POP	HL
-	CP	$88
-	JR	NZ,IMM_PUTDATA2
-
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,(DE)
-	CALL	PPA_WRITEDATA
-	INC	DE
-	INC	HL
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	LD	A,(DE)
-	CALL	PPA_WRITEDATA
-	INC	DE
-	INC	HL
-	LD	A,$00
-	CALL	PPA_WRITECTRL
-	JR	IMM_PUTDATA1
-;
-IMM_PUTDATA2:
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	CALL	PC_SPACE
-	CALL	PRTHEXWORDHL
-	PRTS(" BYTES$")
-	RET
-;
-IMM_PUTDATALEN:
-	PRTS("\r\nPUTDLEN:$")
-	CALL	PC_SPACE
-	CALL	PRTHEXWORDHL
-	PRTS(" BYTES$")
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-IMM_PUTDATALEN1:
-	LD	A,(DE)
-	CALL	PPA_WRITEDATA
-	INC	DE
-	DEC	HL
-	LD	A,$05
-	CALL	PPA_WRITECTRL
-	LD	A,(DE)
-	CALL	PPA_WRITEDATA
-	INC	DE
-	DEC	HL
-	LD	A,$00
-	CALL	PPA_WRITECTRL
-	LD	A,H
-	OR	L
-	JR	NZ,IMM_PUTDATALEN1
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	RET
-;
-;
-;
-IMM_GETSTATUS:
-	PRTS("\r\nSTATUS:$")
-	CALL	IMM_GETBYTE
-	LD	(IMM_STATUS),A
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	CALL	IMM_WAITDONE
-	CP	$B8
-	RET	NZ
-	CALL	IMM_GETBYTE
-	LD	(IMM_STATUS+1),A
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-	RET
-;
-;
-;
-IMM_ENDREAD:
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	LD	A,$0E
-	CALL	PPA_WRITECTRL
-	LD	A,$04
-	CALL	PPA_WRITECTRL
-	RET
-;
-;
-;
-IMM_RUNCMDX:
-	; COPY CMD BYTES FROM (HL)
-	PUSH	BC
-	PUSH	DE
-	LD	BC,6
-	LD	DE,IMM_CMD
-	LDIR
-	POP	DE
-	POP	BC
-;
-IMM_RUNCMD:
-	LD	(IMM_CMDSTK),SP		; FOR ERROR ABORTS
-	LD	(IMM_DSKBUF),DE		; SAVE BUF PTR
-	LD	(IMM_XFRLEN),BC		; SAVE XFER LEN
-	CALL	IMM_CONNECT
-	CALL	IMM_SELECT
-	CALL	IMM_WAITBUSY
-	CALL	IMM_SENDCMD
-;
-IMM_RUNCMD_LOOP:
-	LD	HL,50000		; LONG TIMEOUT HERE
-	CALL	IMM_WAITDONE_HL
-;
-	PRTS("\r\nCMD$")
-	PRTS("LOOP: $")
-	CALL	PRTHEXBYTE
-;
-	CP	$88
-	JR	Z,IMM_RUNCMD_WRITE
-	CP	$98
-	JR	Z,IMM_RUNCMD_READ
-	CP	$B8
-	JR	Z,IMM_RUNCMD_END
-	JR	IMM_CMD_IOERR
-;
-IMM_RUNCMD_WRITE:
-	LD	DE,(IMM_DSKBUF)
-	LD	HL,(IMM_XFRLEN)		; XFER LENGTH
-	CALL	IMM_PUTDATA		; SEND DATA NOW
-	JR	IMM_RUNCMD_LOOP
-;
-IMM_RUNCMD_READ:
-	CALL	IMM_NEGOTIATE
-	CALL	IMM_WAITDONE
-	; CHECK FOR STATUS $98???
-	LD	DE,(IMM_DSKBUF)
-	LD	HL,(IMM_XFRLEN)		; XFER LENGTH
-	CALL	IMM_GETDATA		; GET THE DATA NOW
-	CALL	IMM_ENDREAD
-	JR	IMM_RUNCMD_LOOP
-;
-IMM_RUNCMD_END:
-	CALL	IMM_NEGOTIATE
-	CALL	IMM_WAITDONE
-	; CHECK FOR STATUS $B8???
-	CALL	IMM_GETSTATUS
-	CALL	IMM_ENDREAD
-	CALL	IMM_DISCONNECT
-	XOR	A			; SIGNAL SUCCESS
-	RET
-;
-IMM_CMD_IOERR:
-	LD	A,PPA_STIOERR
-	JR	IMM_CMD_ERR
-;
-IMM_CMD_TIMEOUT:
-	LD	A,PPA_STTO
-	JR	IMM_CMD_ERR
-;
-IMM_CMD_ERR:
-	LD	SP,(IMM_CMDSTK)		; UNWIND STACK
-	PUSH	AF			; SAVE STATUS
-	CALL	IMM_RESETPULSE		; CLEAN UP THE MESS
-	CALL	IMM_DISCONNECT		; MAKE SURE WE ARE OFF THE BUS
-	POP	AF			; RECOVER STATUS
-	JP	PPA_ERR			; ERROR EXIT
-;
-;=============================================================================
-; HARDWARE INTERFACE ROUTINES
-;=============================================================================
-;
-; RESET ALL DEVICES ON BUS
-;
-PPA_RESET:
-	JP	PPA_INITUNIT
-;
-;
-;
-PPA_INITUNIT:
-	;JP	PPA_INITDEV
-	JP	IMM_INITDEV
-;
-; (RE)INITIALIZE DEVICE
-;
-PPA_INITDEV:
-	; INITIALIZE 8255
-	LD	A,(IY+PPA_IOBASE)	; BASE PORT
-	ADD	A,PPA_IOSETUP		; BUMP TO SETUP PORT
-	LD	C,A			; MOVE TO C FOR I/O
-	LD	A,$82			; CONFIG A OUT, B IN, C OUT
-	OUT	(C),A			; DO IT
-	CALL	DELAY
-	
-	CALL	NEWLINE
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	CALL	DELAY
-;
-	; INITIALIZE PPA INTERFACE
-	CALL	PPA_READSTATUS
-	
-	CALL	NEWLINE
-	LD	A,$AA
-	CALL	PPA_WRITEDATA
-
-	CALL	PPA_DISCONNECT
-
-	CALL	PPA_CONNECT
-
-	CALL	NEWLINE
-	;LD	A,$06
-	LD	A,$0E
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	;... CHECK VALUE=$F0
-
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-
-	CALL	NEWLINE
-	;LD	A,$04
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-	CALL	PPA_READSTATUS
-	AND	$F0
-	;... CHECK VALUE=$80
-
-	CALL	PC_SPACE
-	CALL	PRTHEXBYTE
-
-	CALL	PPA_DISCONNECT
-
-	CALL	NEWLINE
-	LD	A,$AA
-	CALL	PPA_WRITEDATA
-	LD	A,$0C			; ???
-	CALL	NEWLINE
-	CALL	PPA_WRITECTRL
-
-	CALL	PPA_CONNECT
-
-	CALL	NEWLINE
-	LD	A,$40
-	CALL	PPA_WRITEDATA
-	LD	A,$08
-	CALL	PPA_WRITECTRL
-	LD	A,$0C
-	CALL	PPA_WRITECTRL
-
-	CALL	PPA_DISCONNECT
-;
-	JP	PPA_NOMEDIA
-;
-	; RECORD STATUS OK
-	XOR	A			; A := 0 (STATUS = OK)
-	LD	(IY+PPA_STAT),A		; SAVE IT
-;
-	RET				; RETURN, A=0, Z SET
-;
-;
-;
-IMM_INITDEV:
-	; INITIALIZE 8255
-	LD	A,(IY+PPA_IOBASE)	; BASE PORT
-	ADD	A,PPA_IOSETUP		; BUMP TO SETUP PORT
-	LD	C,A			; MOVE TO C FOR I/O
-	LD	A,$82			; CONFIG A OUT, B IN, C OUT
-	OUT	(C),A			; DO IT
-	CALL	DELAY
-;
-	CALL	IMM_CONNECT
-	CALL	IMM_RESETPULSE
-	LD	DE,62
-	CALL	VDELAY
-	CALL	IMM_DISCONNECT
-	LD	DE,62
-	CALL	VDELAY
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,512
-	LD	HL,IMM_CMD_READ
-	CALL	IMM_RUNCMDX
-	LD	DE,HB_WRKBUF
-	CALL	Z,DUMP_BUFFER
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,512
-	LD	HL,IMM_CMD_READ
-	CALL	IMM_RUNCMDX
-	LD	DE,HB_WRKBUF
-	CALL	Z,DUMP_BUFFER
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_INQ
-	CALL	IMM_RUNCMDX
-	LD	DE,HB_WRKBUF
-	CALL	Z,DUMP_BUFFER
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	;LD	BC,512
-	LD	BC,0
-	LD	HL,IMM_CMD_WRITE
-	CALL	IMM_RUNCMDX
-	LD	DE,HB_WRKBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	Z,PRTHEXBUF
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,512
-	LD	HL,IMM_CMD_READ2
-	CALL	IMM_RUNCMDX
-	LD	DE,HB_WRKBUF
-	CALL	DUMP_BUFFER
-;
-	LD	DE,HB_WRKBUF
-	LD	BC,0
-	LD	HL,IMM_CMD_SENSE
-	CALL	IMM_RUNCMDX
-	LD	A,16
-	LD	DE,HB_WRKBUF
-	CALL	PRTHEXBUF
-;
-	JP	PPA_NOMEDIA
-;
-IMM_CMD		.DB	$00, $00, $00, $00, $00, $00	; TEMPLATE
-IMM_CMD_READ	.DB	$08, $00, $00, $00, $01, $00	; READ SECTOR $0000
-IMM_CMD_INQ	.DB	$12, $00, $00, $00, $FF, $00	; INQUIRY
-IMM_CMD_TEST	.DB	$00, $00, $00, $00, $00, $00	; TEST UNIT READY
-IMM_CMD_START	.DB	$1B, $00, $00, $00, $01, $00	; START UNIT
-IMM_CMD_SENSE	.DB	$03, $00, $00, $00, $FF, $00	; REQUEST SENSE DATA
-IMM_CMD_WRITE	.DB	$0A, $00, $F0, $00, $01, $00	; READ SECTOR $F000
-IMM_CMD_READ2	.DB	$08, $00, $F0, $00, $01, $00	; READ SECTOR $F000
-
-;
-; CHECK CURRENT DEVICE FOR ERROR STATUS AND ATTEMPT TO RECOVER
-; VIA RESET IF DEVICE IS IN ERROR.
-;
-PPA_CHKERR:
-	LD	A,(IY+PPA_STAT)		; GET STATUS
-	OR	A			; SET FLAGS
-	CALL	NZ,PPA_RESET		; IF ERROR STATUS, RESET BUS
-	RET
-;
-;=============================================================================
-; ERROR HANDLING AND DIAGNOSTICS
-;=============================================================================
+;=============================================================================
+; ERROR HANDLING AND DIAGNOSTICS
+;=============================================================================
 ;
 ; ERROR HANDLERS
 ;
@@ -1395,7 +827,6 @@ PPA_STR_STTO		.TEXT	"TIMEOUT$"
 PPA_STR_STNOTSUP	.TEXT	"NOT SUPPORTED$"
 PPA_STR_STUNK		.TEXT	"UNKNOWN ERROR$"
 ;
-;;;PPA_STR_NO		.TEXT	"NO$"
 PPA_STR_NOHW		.TEXT	"NOT PRESENT$"
 ;
 PPA_STR_MODE_NONE	.TEXT	"NONE$"
@@ -1406,13 +837,11 @@ PPA_STR_MODE_UNK	.TEXT	"???$"
 ; DATA STORAGE
 ;=============================================================================
 ;
-;;;PPA_DSKBUF	.DW	0		; ACTIVE DISK BUFFER
-;
 PPA_DEVNUM	.DB	0		; TEMP DEVICE NUM USED DURING INIT
-IMM_CMDSTK	.DW	0		; STACK PTR FOR CMD ABORTING
-IMM_DSKBUF	.DW	0		; WORKING DISK BUFFER POINTER
-IMM_XFRLEN	.DW	0		; WORKING TRANSFER LENGTH
-IMM_STATUS	.DB	0, 0		; CMD RESULT STATUS
+PPA_CMDSTK	.DW	0		; STACK PTR FOR CMD ABORTING
+PPA_DSKBUF	.DW	0		; WORKING DISK BUFFER POINTER
+PPA_XFRLEN	.DW	0		; WORKING TRANSFER LENGTH
+PPA_CMDSTAT	.DB	0, 0		; CMD RESULT STATUS
 ;
 PPA_TYPE_MAP:
 		.DW	PPA_STR_NONE
@@ -1421,6 +850,15 @@ PPA_TYPE_MAP:
 PPA_STR_NONE	.DB	"<NOT PRESENT>$"
 PPA_STR_MG014	.DB	"MG014$"
 ;
+; SCSI COMMAND TEMPLATES (LENGTH PREFIXED)
+;
+		.DB	6
+PPA_CMD_RW	.DB	$00, $00, $00, $00, $01, $00	; READ/WRITE SECTOR
+		.DB	6
+PPA_CMD_SENSE	.DB	$03, $00, $00, $00, $FF, $00	; REQUEST SENSE DATA
+		.DB	10
+PPA_CMD_RDCAP	.DB	$25, $00, $00, $00, $00, $00, $00, $00, $00, $00 ; READ CAPACITY
+;
 ; PPA DEVICE CONFIGURATION TABLE
 ;
 PPA_CFG:
diff --git a/Source/HBIOS/ppp.asm b/Source/HBIOS/ppp.asm
index c8cc27d6..ac61f866 100644
--- a/Source/HBIOS/ppp.asm
+++ b/Source/HBIOS/ppp.asm
@@ -904,7 +904,7 @@ PPPSD_GETCSD:
 	CALL	PPP_SNDCMD		; SEND COMMAND
 	RET	NZ			; ABORT ON ERROR
 
-	LD	B,16			; GET 4 BYTES
+	LD	B,16			; GET 16 BYTES
 	LD	HL,PPPSD_CSDBUF
 PPPSD_GETCSD1:
 	CALL	PPP_GETBYTE
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index f057e926..be353573 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -447,6 +447,16 @@ SPD_UNSUP	.EQU	0		; PLATFORM CAN CHANGE SPEEDS BUT IS UNSUPPORTED
 SPD_HIGH	.EQU	1		; PLATFORM CAN CHANGE SPEED, STARTS HIGH
 SPD_LOW		.EQU	2		; PLATFORM CAN CHANGE SPEED, STARTS LOW
 ;
+; SCSI COMMAND CODES (SHOULD BE IT IT'S OWN FILE)
+;
+SCSI_CMD_READ	.EQU	$08
+SCSI_CMD_INQ	.EQU	$12
+SCSI_CMD_TEST	.EQU	$00
+SCSI_CMD_START	.EQU	$1B
+SCSI_CMD_SENSE	.EQU	$03
+SCSI_CMD_WRITE	.EQU	$0A
+SCSI_CMD_RDCAP	.EQU	$25
+;
 #INCLUDE "build.inc"		; INCLUDE USER CONFIG, ADD VARIANT, TIMESTAMP, & ROMSIZE
 ;
 ; INCLUDE Z180 REGISTER DEFINITIONS
diff --git a/Source/ver.inc b/Source/ver.inc
index 1a5a4399..83cbe21f 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	3
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.3.0-dev.15"
+#DEFINE BIOSVER	"3.3.0-dev.16"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index d9e32aa6..3f43e883 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	3
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.3.0-dev.15"
+	db	"3.3.0-dev.16"
 	endm