diff --git a/Doc/RomWBW Applications.pdf b/Doc/RomWBW Applications.pdf
index ed28704b..4f21039c 100644
Binary files a/Doc/RomWBW Applications.pdf and b/Doc/RomWBW Applications.pdf differ
diff --git a/Doc/RomWBW Architecture.pdf b/Doc/RomWBW Architecture.pdf
index fa9ec503..2fee8c60 100644
Binary files a/Doc/RomWBW Architecture.pdf and b/Doc/RomWBW Architecture.pdf differ
diff --git a/Doc/RomWBW Disk Catalog.pdf b/Doc/RomWBW Disk Catalog.pdf
index 1d9cf04e..39843e0c 100644
Binary files a/Doc/RomWBW Disk Catalog.pdf and b/Doc/RomWBW Disk Catalog.pdf differ
diff --git a/Doc/RomWBW Getting Started.pdf b/Doc/RomWBW Getting Started.pdf
index 8f0d1348..0ebfa20f 100644
Binary files a/Doc/RomWBW Getting Started.pdf and b/Doc/RomWBW Getting Started.pdf differ
diff --git a/ReadMe.md b/ReadMe.md
index 9cd672ab..a37f7228 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -3,7 +3,7 @@
 ## Z80/Z180 System Software
 
 Version 3.1 Pre-release  
-Wednesday 13 May 2020
+Saturday 16 May 2020
 
 Wayne Warthen <wwarthen@gmail.com>
 
@@ -775,6 +775,10 @@ tracks. `CPMLDR.SYS` chain loads `CPM3.SYS`.
     used to read the current date/time for file stamping, etc. You can
     use the `RTC` app to set the RTC clock.
 
+  - The `COPYSYS` command described in the DRI CP/M 3 documentatin is
+    not provided with RomWBW. The RomWBW `SYSCOPY` command is used
+    instead.
+
 ## Simeon Cran’s ZPM3
 
 ZPM3 is an interesting combination of the features of both CP/M 3 and
diff --git a/ReadMe.txt b/ReadMe.txt
index 4ce8acd7..81a3de1e 100644
--- a/ReadMe.txt
+++ b/ReadMe.txt
@@ -3,7 +3,7 @@ RomWBW
 Z80/Z180 System Software
 
 Version 3.1 Pre-release
-Wednesday 13 May 2020
+Saturday 16 May 2020
 
 Wayne Warthen wwarthen@gmail.com
 
@@ -804,6 +804,9 @@ Notes
     to read the current date/time for file stamping, etc. You can use
     the RTC app to set the RTC clock.
 
+-   The COPYSYS command described in the DRI CP/M 3 documentatin is not
+    provided with RomWBW. The RomWBW SYSCOPY command is used instead.
+
 Simeon Cran’s ZPM3
 
 ZPM3 is an interesting combination of the features of both CP/M 3 and
diff --git a/Source/Apps/SysCopy.asm b/Source/Apps/SysCopy.asm
index 144f9536..10b85bd2 100644
--- a/Source/Apps/SysCopy.asm
+++ b/Source/Apps/SysCopy.asm
@@ -17,6 +17,7 @@
 ; Change Log:
 ;   2016-04-24 [WBW] Updated to preserve MBR partition table
 ;   2020-02-17 [WBW] Updated for CP/M 3
+;   2020-05-16 [WBW] Fixed SPT for CP/M 3
 ;_______________________________________________________________________________
 ;
 ; ToDo:
@@ -441,6 +442,16 @@ setdsk:
 	ld	c,(hl)
 	inc	hl
 	ld	b,(hl)		; BC := sectors per track
+	; handle CP/M 3 physical sector size
+	ld	a,(v3os)	; CP/M 3 or greater?
+	or	a		; set flags
+	jr	z,setdsk1	; if not, continue
+	; adjust SPT for CP/M 3 physical sector size
+	srl	b		; divide SPT by 4
+	rr	c
+	srl	b
+	rr	c
+setdsk1:
 	ld	(actspt),bc	; save it
 	; ensure there are system tracks (verify that offset field in DPB is not zero)
 	ld	de,12		; offset field is 12 bytes into DPB
@@ -952,7 +963,7 @@ bpb_hl	.dw	0		; reg HL
 ;
 ; Messages
 ;
-msgban1	.db	"SYSCOPY v2.0 for RomWBW CP/M, 17-Feb-2020$"
+msgban1	.db	"SYSCOPY v2.1 for RomWBW CP/M, 15-May-2020$"
 msgv2	.db	" (CP/M 2 Mode)$"
 msgv3	.db	" (CP/M 3 Mode)$"
 msgban2	.db	"Copyright 2020, Wayne Warthen, GNU GPL v3$"
diff --git a/Source/CPM3/diskio.z80 b/Source/CPM3/diskio.z80
index 45df4372..90c0eb1c 100644
--- a/Source/CPM3/diskio.z80
+++ b/Source/CPM3/diskio.z80
@@ -431,7 +431,7 @@ media:
 	ld	a,e			; resultant media id to accum
 	ld	(medid),a		; save media id
 	or	a			; set flags, 0 is no media
-	jp	z,err_diskio		; handle no media error
+	jp	z,err_nodisk		; handle no media error
 	
 	; Initialize slice start LBA & sectors per slice
 	ld	hl,0			; assume slice starts
@@ -769,27 +769,21 @@ cin$echo1:
 
 err_nodisk:
 	ld	hl,str_err_nodisk
-	jr	err
+	jr	err_perm
 err_noslice:
 	ld	hl,str_err_noslice
-	jr	err
+	jr	err_perm
+err_perm:
+	call	prt_err
+	jr	err_ret
 err_diskio:
-	ld	hl,str_err_diskio
-	jr	err
-err_sig:
-	ld	hl,str_err_sig
-	jr	err
-err_api:
-	ld	hl,str_err_api
-	jr	err
-err:
+	cp	-10			; HBIOS read only error
+	jr	z,err_rdonly		; if so, handle special
 	ld	a,(@ermde)		; get error mode
 	cp	0FFh			; FFh means suppress
 	jr	z,err_ret		; if so, go to err return
-	push	hl
-	call	?pderr
-	pop	hl
-	call	?pmsg
+	ld	hl,str_err_diskio
+	call	prt_err
 	ld	hl,str_err_retry
 	call	?pmsg
 	call	cin$echo
@@ -797,16 +791,29 @@ err:
 	jr	nz,err_ret		; return error to caller
 	ld	hl,(retry$adr)		; get retry address
 	jp	(hl)			; and go there
+err_rdonly:
+	ld	hl,str_err_rdonly
+	call	prt_err
+	ld	a,2			; signal readonly media
+	ret
+prt_err:
+	ld	a,(@ermde)		; get error mode
+	cp	0FFh			; FFh means suppress
+	ret	z			; if so, go to err return
+	push	hl
+	call	?pderr
+	pop	hl
+	jp	?pmsg
 err_ret:
-	ld	a,1			; signal I/O error
+	ld	a,0FFh			; signal error
 	ret				; and done
 
-str_err_retry	db	", Retry (Y/N) ? ",0
+str_err_retry	db	", Retry (Y/N)?",0
 str_err_nodisk	db	", No disk",0
 str_err_noslice	db	", No slice",0
 str_err_diskio	db	", Disk I/O",0
-str_err_sig	db	", No system",0
-str_err_api	db	", API failure",0
+str_err_rdonly	db	", Read Only",0
+str_err_prefix	db	13,10,"BIOS Error: ",0
 
 retry$adr	dw	?wboot		; error retry address
 curdph		dw	0		; working dph value
diff --git a/Source/Doc/GettingStarted.md b/Source/Doc/GettingStarted.md
index a8be357a..f63ef2e3 100644
--- a/Source/Doc/GettingStarted.md
+++ b/Source/Doc/GettingStarted.md
@@ -823,6 +823,9 @@ system tracks.  `CPMLDR.SYS` chain loads `CPM3.SYS`.
 used to read the current date/time for file stamping, etc.  You can
 use the `RTC` app to set the RTC clock.
 
+- The `COPYSYS` command described in the DRI CP/M 3 documentatin is
+not provided with RomWBW.  The RomWBW `SYSCOPY` command is used instead.
+
 ## Simeon Cran's ZPM3
 
 ZPM3 is an interesting combination of the features of both CP/M 3 and
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 3094c843..21b8ee82 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -2186,7 +2186,9 @@ RTC_DISPATCH:
 	RET
 ;
 RTC_DISPERR:
-	OR	$FF
+	;CALL	PANIC
+	LD	A,ERR_NOHW
+	OR	A
 	RET
 ;
 ; SET RTC DISPATCH ADDRESS, USED BY RTC DRIVERS DURING INIT
@@ -2339,7 +2341,9 @@ SYS_RESET:
 	JR	Z,SYS_RESWARM
 	CP	BF_SYSRES_COLD
 	JR	Z,SYS_RESCOLD
-	OR	$FF			; SIGNAL ERROR
+	;CALL	PANIC
+	LD	A,ERR_NOFUNC
+	OR	A			; SIGNAL ERROR
 	RET
 ;
 ; SOFT RESET HBIOS, RELEASE HEAP MEMORY NOT USED BY HBIOS
@@ -2450,8 +2454,9 @@ SYS_ALLOC:
 ; ALL OTHER REGISTERS PRESERVED
 ;
 SYS_FREE:
-	CALL	PANIC			; NOT YET IMPLEMENTED
-	OR	$FF
+	;CALL	PANIC			; NOT YET IMPLEMENTED
+	LD	A,ERR_NOTIMPL		; NOT YET INMPLEMENTED
+	OR	A			; SET FLAGS
 	RET
 ;
 ; GET SYSTEM INFORMATION
@@ -2481,7 +2486,9 @@ SYS_GET:
 	JR	Z,SYS_GETMEMINFO
 	CP	BF_SYSGET_BNKINFO
 	JR	Z,SYS_GETBNKINFO
-	OR	$FF			; SIGNAL ERROR
+	;CALL	PANIC
+	LD	A,ERR_NOFUNC		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET
 ;
 ; GET TIMER
@@ -2619,7 +2626,9 @@ SYS_SET:
 	JR	Z,SYS_SETSECS
 	CP	BF_SYSSET_BOOTINFO
 	JR	Z,SYS_SETBOOTINFO
-	OR	$FF			; SIGNAL ERROR
+	;CALL	PANIC
+	LD	A,ERR_NOFUNC		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET
 ;
 ; SET BOOT INFORMATION
@@ -2714,7 +2723,9 @@ SYS_INT:
 	JR	Z,SYS_INTGET
 	CP	BF_SYSINT_SET
 	JR	Z,SYS_INTSET
-	OR	$FF			; SIGNAL ERROR
+	;CALL	PANIC
+	LD	A,ERR_NOFUNC		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET
 ;
 ; GET INTERRUPT SYSTEM INFORMATION
@@ -2740,8 +2751,9 @@ SYS_INTINFO:
 ;
 SYS_INTVECADR:
 #IF (INTMODE == 0)
-	CALL	PANIC			; INVALID FOR INT MODE 0
-	OR	$FF
+	;CALL	PANIC			; INVALID FOR INT MODE 0
+	LD	A,ERR_BADCFG		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET
 #ENDIF
 #IF (INTMODE == 1)
@@ -2755,8 +2767,9 @@ SYS_INTVECADR:
 	LD	A,E			; INCOMING INDEX POSITION TO A
 	CP	C			; COMPARE TO VECTOR COUNT
 	JR	C,SYS_INTGET1		; CONTINUE IF POSITION IN RANGE
-	CALL	PANIC			; ELSE ERROR
-	OR	$FF
+	;CALL	PANIC			; ELSE ERROR
+	LD	A,ERR_RANGE		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET
 SYS_INTGET1:
 	OR	A			; CLEAR CARRY
@@ -2935,13 +2948,13 @@ HB_DISPCALL:
 	; CHECK INCOMING UNIT INDEX IN C FOR VAILIDITY
 	LD	A,C			; A := INCOMING DISK UNIT INDEX
 	CP	(IY-1)			; COMPARE TO COUNT
-	JR	NC,HB_DISPERR		; HANDLE INVALID UNIT INDEX
+	JR	NC,HB_FUNCERR		; HANDLE INVALID UNIT INDEX
 
 	; CHECK FUNCTION INDEX FOR VALIDITY
 	LD	A,B			; A := INCOMING FUNCTION NUMBER
 	AND	$0F			; LOW NIBBLE ONLY FOR FUNC INDEX
 	CP	(IY-3)			; CHECK FN NUM AGAINST MAX
-	JR	NC,HB_DISPERR		; HANDLE FN NUM OUT OF RANGE ERROR
+	JR	NC,HB_UNITERR		; HANDLE FN NUM OUT OF RANGE ERROR
 
 	; BUMP IY TO ACTUAL XXX_TBL ENTRY FOR INCOMING UNIT INDEX
 	PUSH	BC			; SAVE BC
@@ -2972,10 +2985,17 @@ HB_DISPCALL:
 
 	RET				; JUMP TO DRIVER FUNC ADR ON TOS
 ;
-HB_DISPERR:
-	CALL	PANIC			; PANIC
-	OR	$FF			; SIGNAL ERROR
-	RET				; AND RETURN VIA DISPEXIT
+HB_FUNCERR:
+	;CALL	PANIC
+	LD	A,ERR_NOFUNC		; SIGNAL ERROR
+	OR	A			; SET FLAGS
+	RET
+;
+HB_UNITERR:
+	;CALL	PANIC
+	LD	A,ERR_NOUNIT		; SIGNAL ERROR
+	OR	A			; SET FLAGS
+	RET
 ;
 ; ADD AN ENTRY TO THE UNIT TABLE AT ADDRESS IN HL
 ;   BC: DRIVER FUNCTION TABLE
@@ -3061,8 +3081,10 @@ HB_ALLOC:
 HB_ALLOC1:
 	; ERROR RETURN
 	POP	DE			; RESTORE INCOMING DE
-	OR	$FF			; SIGNAL ERROR
-	RET				; AND RETURN
+	;CALL	PANIC
+	LD	A,ERR_NOMEM		; SIGNAL ERROR
+	OR	A			; SET FLAGS
+	RET
 ;
 HB_TMPSZ	.DW	0
 HB_TMPREF	.DW	0
diff --git a/Source/HBIOS/hbios.inc b/Source/HBIOS/hbios.inc
index 1452fe27..d1d8e5f4 100644
--- a/Source/HBIOS/hbios.inc
+++ b/Source/HBIOS/hbios.inc
@@ -116,6 +116,23 @@ BF_SYSINT_SET		.EQU	$20	; SET INT VECTOR ADDRESS
 ;
 CIO_CONSOLE		.EQU	$80	; CIO UNIT NUM FOR CUR CON
 ;
+; HBIOS GLOBAL ERROR RETURN VALUES
+;
+ERR_NONE		.EQU	0	; SUCCESS
+;
+ERR_UNDEF		.EQU	-1	; UNDEFINED ERROR
+ERR_NOTIMPL		.EQU	-2	; FUNC NOT IMPLEMENTED
+ERR_NOFUNC		.EQU	-3	; INVALID FUNCTION
+ERR_NOUNIT		.EQU	-4	; INVALID UNIT NUMBER
+ERR_NOMEM		.EQU	-5	; OUT OF MEMORY
+ERR_RANGE		.EQU	-6	; PARAMETER OUT OF RANGE
+ERR_NOMEDIA		.EQU	-7	; MEDIA NOT PRESENT
+ERR_NOHW		.EQU	-8	; HARDWARE NOT PRESENT
+ERR_IO			.EQU	-9	; I/O ERROR
+ERR_READONLY		.EQU	-10	; WRITE REQ TO READ-ONLY MEDIA	
+ERR_TIMEOUT		.EQU	-11	; DEVICE TIMEOUT
+ERR_BADCFG		.EQU	-12	; INVALID CONFIGURATION
+;
 ; MEDIA ID VALUES
 ;
 MID_NONE	.EQU	0
diff --git a/Source/HBIOS/md.asm b/Source/HBIOS/md.asm
index 2b9c9c0a..9d290c0a 100644
--- a/Source/HBIOS/md.asm
+++ b/Source/HBIOS/md.asm
@@ -190,7 +190,8 @@ MD_WRITE:
 	OR	A			; SET FLAGS TO TEST FOR ROM (UNIT 0)
 	JR	NZ,MD_RW		; NOT ROM, SO OK TO WRITE, CONTINUE
 	LD	E,0			; UNIT IS READ ONLY, ZERO SECTORS WRITTEN
-	OR	$FF			; SIGNAL ERROR
+	LD	A,ERR_READONLY		; SIGNAL ERROR
+	OR	A			; SET FLAGS
 	RET				; AND DONE
 ;
 ;
diff --git a/Source/Images/Common/COMP.COM b/Source/Images/Common/COMP.COM
deleted file mode 100644
index d91f079f..00000000
Binary files a/Source/Images/Common/COMP.COM and /dev/null differ
diff --git a/Source/Images/Common/COMPARE.COM b/Source/Images/Common/COMPARE.COM
new file mode 100644
index 00000000..29fa41e6
Binary files /dev/null and b/Source/Images/Common/COMPARE.COM differ