diff --git a/Source/HBIOS/espsd.asm b/Source/HBIOS/espsd.asm
index 63d3e00c..5e00cfe7 100644
--- a/Source/HBIOS/espsd.asm
+++ b/Source/HBIOS/espsd.asm
@@ -112,14 +112,14 @@ ESPSD_STNOTRDY		.EQU	-4
 ;
 ; PER DEVICE DATA OFFSETS IN CFG BLOCK
 ;
-ESPSD_DEV		.EQU	0		; OFFSET OF DEVICE NUMBER (BYTE)
-ESPSD_ROLE		.EQU	1		; 0=PRIMARY, 1=SECONDARY
-ESPSD_IOBASE		.EQU	2		; IO BASE ADDRESS (BYTE)
-ESPSD_STAT		.EQU	3		; LAST STATUS (BYTE)
-ESPSD_MEDCAP		.EQU	4		; MEDIA CAPACITY (DWORD)
-ESPSD_LBA		.EQU	8		; OFFSET OF LBA (DWORD)
-;
-ESPSD_CFGSIZ		.EQU	12		; SIZE OF CFG TBL ENTRIES
+ESPSD_DEV		.EQU	0	; OFFSET OF DEVICE NUMBER (BYTE)
+ESPSD_ROLE		.EQU	1	; 0=PRIMARY, 1=SECONDARY
+ESPSD_IOBASE		.EQU	2	; IO BASE ADDRESS (BYTE)
+ESPSD_STAT		.EQU	3	; LAST STATUS (BYTE)
+ESPSD_MEDCAP		.EQU	4	; MEDIA CAPACITY (DWORD)
+ESPSD_LBA		.EQU	8	; OFFSET OF LBA (DWORD)
+;                                       
+ESPSD_CFGSIZ		.EQU	12	; SIZE OF CFG TBL ENTRIES
 ;
 ESPSD_CFGTBL:
 ;
@@ -205,7 +205,7 @@ ESPSD_INIT:
 ;
 	XOR	A			; ZERO ACCUM
 	LD	(ESPSD_DEVNUM),A	; INIT DEV UNIT NUM FOR DYNAMIC ASSIGNMENT
-	LD	IY,ESPSD_CFGTBL	; POINT TO START OF CONFIG TABLE
+	LD	IY,ESPSD_CFGTBL		; POINT TO START OF CONFIG TABLE
 ;
 ESPSD_INIT1:
 	LD	A,(IY)			; LOAD FIRST BYTE TO CHECK FOR END
@@ -216,14 +216,14 @@ ESPSD_INIT1:
 ;
 ESPSD_INIT2:
 	CALL	NEWLINE			; FORMATTING
-	PRTS("ESPSD:$")		; TAG
+	PRTS("ESPSD:$")			; TAG
 ;
 	PRTS(" IO=0x$")			; LABEL FOR IO ADDRESS
 	LD	A,(IY+ESPSD_IOBASE)	; GET IO BASE ADDRES
 	CALL	PRTHEXBYTE		; DISPLAY IT
 ;
 	BIT	0,(IY+ESPSD_ROLE)	; GET ROLE BIT
-	JR	NZ,ESPSD_INIT2A	; JUMP IF SECONDARY
+	JR	NZ,ESPSD_INIT2A		; JUMP IF SECONDARY
 	PRTS(" PRIMARY$")		; SHOW PRIMATY
 	JR	ESPSD_INIT2B		; JUMP AHEAD
 ESPSD_INIT2A:
@@ -238,7 +238,7 @@ ESPSD_INIT3:
 	CALL	ESPSD_INIT5		; REGISTER & INIT DEVICE
 ;
 ESPSD_INIT4:
-	LD	DE,ESPSD_CFGSIZ	; SIZE OF CFG TABLE ENTRY
+	LD	DE,ESPSD_CFGSIZ		; SIZE OF CFG TABLE ENTRY
 	ADD	IY,DE			; BUMP POINTER
 	JP	ESPSD_INIT1		; AND LOOP
 ;
@@ -261,7 +261,7 @@ ESPSD_INIT5:
 #ENDIF
 	RET	NZ
 ;
-	CALL	ESPSD_PRTPREFIX	; TAG FOR ACTIVE DEVICE
+	CALL	ESPSD_PRTPREFIX		; TAG FOR ACTIVE DEVICE
 ;
 	; PRINT STORAGE CAPACITY (BLOCK COUNT)
 	PRTS(" BLOCKS=0x$")		; PRINT FIELD LABEL
@@ -304,7 +304,7 @@ ESPSD_FNTBL:
 ESPSD_VERIFY:
 ESPSD_FORMAT:
 ESPSD_DEFMED:
-	SYSCHKERR(ERR_NOTIMPL)			; NOT IMPLEMENTED
+	SYSCHKERR(ERR_NOTIMPL)		; NOT IMPLEMENTED
 	RET
 ;
 ;
@@ -418,7 +418,7 @@ ESPSD_GEOM:
 	;;;CALL	COUT
 	; FOR LBA, WE SIMULATE CHS ACCESS USING 16 HEADS AND 16 SECTORS
 	; RETURN HS:CC -> DE:HL, SET HIGH BIT OF D TO INDICATE LBA CAPABLE
-	CALL	ESPSD_CAP			; GET TOTAL BLOCKS IN DE:HL, BLOCK SIZE TO BC
+	CALL	ESPSD_CAP		; GET TOTAL BLOCKS IN DE:HL, BLOCK SIZE TO BC
 	LD	L,H			; DIVIDE BY 256 FOR # TRACKS
 	LD	H,E			; ... HIGH BYTE DISCARDED, RESULT IN HL
 	LD	D,16 | $80		; HEADS / CYL = 16, SET LBA CAPABILITY BIT
@@ -637,7 +637,7 @@ ESPSD_BLKWRITE1:
 	LD	A,E			; RESULT TO ACCUM
 	OR	A			; SET FLAGS
 	RET	Z			; GOOD RETURN
-	LD	A,ESPSD_STIOERR	; CALL THIS AN IO ERROR
+	LD	A,ESPSD_STIOERR		; CALL THIS AN IO ERROR
 	OR	A			; SET FLAGS
 	RET				; DONE
 ;
@@ -649,7 +649,7 @@ ESPSD_BLKWRITE1:
 ;
 ESPSD_CMD:
 	PUSH	DE
-	LD	E,$33
+	LD	E,$33			; COMMAND PREFIX BYTE
 	CALL	ESPSD_PUTBYTE
 	POP	DE
 	RET	NZ
@@ -659,7 +659,7 @@ ESPSD_CMD:
 ;
 ESPSD_CMD_SLOW:
 	PUSH	DE
-	LD	E,$33
+	LD	E,$33			; COMMAND PREFIX BYTE
 	CALL	ESPSD_PUTBYTE_SLOW
 	POP	DE
 	RET	NZ
@@ -699,7 +699,9 @@ ESPSD_PUTBYTE2:
 ;
 ESPSD_PUTBYTE_SLOW:
 	PUSH	HL
-	LD	HL,50 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	;;;LD	HL,50 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	LD	HL,100 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	;;;LD	HL,1000 * CPUMHZ	; CPU SPEED SCALED TIMEOUT
 	;;;LD	HL,0			; *DEBUG*
 ESPSD_PUTBYTE_SLOW1:
 	PUSH	HL
@@ -751,7 +753,9 @@ ESPSD_GETBYTE2:
 ;
 ESPSD_GETBYTE_SLOW:
 	PUSH	HL
-	LD	HL,50 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	;;;LD	HL,50 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	LD	HL,100 * CPUMHZ		; CPU SPEED SCALED TIMEOUT
+	;;;LD	HL,1000 * CPUMHZ	; CPU SPEED SCALED TIMEOUT
 	;;;LD	HL,0			; *DEBUG*
 ESPSD_GETBYTE_SLOW1:
 	PUSH	HL
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index eae5fba4..d13312ca 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -4427,10 +4427,9 @@ HB_DSKREAD:
 	LD	A,C			; GET DISK UNIT NUMBER
 	LD	B,A			; PUT IN B FOR LOOP COUNTER
 	INC	B			; LOOP ONE EXTRA TIME TO HANDLE UNIT=0
-	XOR	A			; START WITH ACCUM ZERO
-	SCF				; ... AND CF SET
+	LD	A,%10000000		; START WITH HIGH BIT SET
 HB_DSKREAD0:
-	RLA				; ROTATE BIT
+	RLCA				; ROTATE BIT
 	DJNZ	HB_DSKREAD0		; ... UNTIL IN PROPER LOCATION
 	LD	(HB_DSKBIT),A		; SAVE IT FOR DIAGNOSTICS
 #ENDIF
diff --git a/Source/HBIOS/lpt.asm b/Source/HBIOS/lpt.asm
index f8703d7e..795a28ac 100644
--- a/Source/HBIOS/lpt.asm
+++ b/Source/HBIOS/lpt.asm
@@ -13,21 +13,21 @@
 ;  IBM PC STANDARD PARALLEL PORT (SPP):
 ;  - NHYODYNE PRINT MODULE
 ;
-;  PORT 0 (OUTPUT):
+;  DATA (BASE PORT + 0, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     | PD7   | PD6   | PD5   | PD4   | PD3   | PD2   | PD1   | PD0   |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  PORT 1 (INPUT):
+;  STATUS (BASE PORT + 1, INPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     | /BUSY | /ACK  | POUT  | SEL   | /ERR  | 0     | 0     | 0     |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  PORT 2 (OUTPUT):
+;  CONTROL (BASE PORT + 2, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
@@ -39,21 +39,21 @@
 ;  MG014 STYLE INTERFACE:
 ;  - RCBUS MG014 MODULE
 ;
-;  PORT 0 (OUTPUT):
+;  DATA (BASE PORT + 0, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     | PD7   | PD6   | PD5   | PD4   | PD3   | PD2   | PD1   | PD0   |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  PORT 1 (INPUT):
+;  STATUS (BASE PORT + 1, INPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     |       |       |       | /ERR  | SEL   | POUT  | BUSY  | /ACK  |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  PORT 2 (OUTPUT):
+;  CONTROL (BASE PORT + 2, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
@@ -65,21 +65,21 @@
 ;  S100 STYLE INTERFACE:
 ;  - S100 FPGA Z80
 ;
-;  BASE I/O PORT (OUTPUT):
+;  DATA (BASE PORT + 0, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     | PD7   | PD6   | PD5   | PD4   | PD3   | PD2   | PD1   | PD0   |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  STATUS PORT (INPUT, BASE I/O - 1):
+;  STATUS (BASE PORT + 0, INPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;     |       |       |       |       |       |       | BUSY  | /ACK  |
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
 ;
-;  CONTROL PORT (OUTPUT, BASE I/O - 1):
+;  CONTROL (BASE PORT - 1, OUTPUT):
 ;
 ;	D7	D6	D5	D4	D3	D2	D1	D0
 ;     +-------+-------+-------+-------+-------+-------+-------+-------+
@@ -168,13 +168,18 @@ LPT_IN:
 ; BYTE OUTPUT
 ;
 LPT_OUT:
+	; WAIT WHILE PRINTER IS BUSY
 	CALL	LPT_OST			; READY TO SEND?
 	JR	Z,LPT_OUT		; LOOP IF NOT
+;
+	; SET DATA PORT BITS
 	LD	C,(IY+3)		; PORT 0 (DATA)
 	EZ80_IO
 	OUT	(C),E			; OUTPUT DATA TO PORT
+;
+	; SET STROBE
 #IF (LPTMODE == LPTMODE_SPP)
-	LD	A,%00001101		; SELECT & STROBE, LEDS OFF
+	LD	A,%00001101		; SELECT & STROBE, LED OFF
 #ENDIF
 #IF (LPTMODE == LPTMODE_MG014)
 	LD	A,%00000100		; SELECT & STROBE, LED OFF
@@ -192,6 +197,8 @@ LPT_OUT:
 	EZ80_IO
 	OUT	(C),A			; OUTPUT DATA TO PORT
 	CALL	DELAY
+;
+	; CLEAR STROBE
 #IF (LPTMODE == LPTMODE_SPP)
 	LD	A,%00001100		; SELECT, LEDS OFF
 #ENDIF
@@ -199,11 +206,12 @@ LPT_OUT:
 	LD	A,%00000101		; SELECT, LED OFF
 #ENDIF
 #IF (LPTMODE == LPTMODE_S100)
-	LD	A,%11111111		; STROBE
+	LD	A,%11111111		; CLEAR STROBE
 #ENDIF
 	EZ80_IO
 	OUT	(C),A			; OUTPUT DATA TO PORT
 	CALL	DELAY
+;
 	XOR	A			; SIGNAL SUCCESS
 	RET
 ;
@@ -215,21 +223,19 @@ LPT_IST:
 	RET				; DONE
 ;
 ; OUTPUT STATUS
+; 0 = BUSY, 1 = READY
 ;
 LPT_OST:
 	LD	C,(IY+3)		; BASE PORT
 #IF ((LPTMODE == LPTMODE_SPP) | (LPTMODE == LPTMODE_MG014))
 	INC	C			; SELECT STATUS PORT
-#ENDIF
-#IF (LPTMODE == LPTMODE_S100)
-	DEC	C			; SELECT STATUS PORT
 #ENDIF
 	EZ80_IO
 	IN	A,(C)			; GET STATUS INFO
 #IF (LPTMODE == LPTMODE_SPP)
 	AND	%10000000		; ISOLATE /BUSY
 #ENDIF
-#IF (LPTMODE == LPTMODE_MG014)
+#IF ((LPTMODE == LPTMODE_MG014) | (LPTMODE == LPTMODE_S100))
 	AND	%00000010		; ISOLATE BUSY
 	XOR	%00000010		; INVERT TO READY
 #ENDIF
@@ -295,6 +301,7 @@ LPT_INITDEV0:
 	LD	A,$FF			; INIT VALUE
 	EZ80_IO
 	OUT	(C),A			; DO IT
+	XOR	A			; SIGNAL SUCCESS
 	RET				; RETURN
 #ENDIF
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index b5ab0bb1..54a84855 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	6
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.6.0-dev.19"
+#DEFINE BIOSVER	"3.6.0-dev.20"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index 1b841c39..98689530 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	6
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.6.0-dev.19"
+	db	"3.6.0-dev.20"
 	endm