diff --git a/Messages.z80 b/Messages.z80
index cb6c838..5c2b74a 100644
--- a/Messages.z80
+++ b/Messages.z80
@@ -39,6 +39,12 @@ Version_Msg:	DB	"DSS Drive Formatter v"
 .Size		EQU	$-Version_Msg
  ASSERT	Version_Msg.Size < 80+4, "ERROR: Version_Msg to long!"
  ;-----------------------------------------------------------------------
+ 
+ 
+ ;-----------------------------------------------------------------------
+Error_Msg:	DZ	"\r\n\r\nError!!!\r\n\r\n"
+ ;-----------------------------------------------------------------------
+
 
  ;-----------------------------------------------------------------------
  ;!FIXIT Color settings 
@@ -49,6 +55,9 @@ col_cmd		EQU	16
 PARAMS_MSG:	BYTE	"\r\nDrive "
 .disk		BYTE	"A: "
 		BYTE	"will be formatted using the current settings:\r\n\r\n"
+		BYTE	"Partition size:\t",	col_cmd,col_magenta,	"%S bytes",	col_cmd,col_white, "\r\n"
+		BYTE	"Available size:\t",	col_cmd,col_magenta,	"%S bytes",	col_cmd,col_white, "\r\n"
+		BYTE	"Unused space:\t",	col_cmd,col_magenta,	"%lu bytes",	col_cmd,col_white, "\r\n"
 		BYTE	"Clusters:\t",		col_cmd,col_magenta,	"%lu",		col_cmd,col_white, "\r\n"
 		BYTE	"Cluster size:\t",	col_cmd,col_magenta,	"%u bytes",	col_cmd,col_white, "\r\n"
 		BYTE	"File system:\t",	col_cmd,col_magenta,	"%S",		col_cmd,col_white, "\r\n"
@@ -57,12 +66,17 @@ PARAMS_MSG:	BYTE	"\r\nDrive "
 		BYTE	'Press "Y" for format or any other key to exit', "\r\n"
 		BYTE	0
 .ptr:		WORD	PARAMS_MSG
+		WORD	.fullSize
+		WORD	.dataSize
+.unused:	DWORD	0
 .Clusters:	DWORD	0
 .Clu_size:	WORD	0
-.FAT:		WORD	.FATtxt
+		WORD	.FATtxt
 .Serial:	DWORD	0
-.Label:		WORD	.LabelTxt
+		WORD	.LabelTxt
 ;
 .FATtxt:	DZ	'FAT  '
 .LabelTxt:	DZ	'NO LABEL   '
+.fullSize:	BYTE	'               ',0
+.dataSize:	BYTE	'               ',0
 ;-----------------------------------------------------------------------
diff --git a/data.z80 b/data.z80
index 000854d..152f5d0 100644
--- a/data.z80
+++ b/data.z80
@@ -8,6 +8,17 @@ FAT16		EQU	2	; 
 FAT12		EQU	3	; заодно и множитель
 FAT32		EQU	4	; заодно и множитель
 ;
+;
+MaxClustersNumber:
+.FAT12		EQU	4084
+.FAT16		EQU	65524
+;
+MaxDataSectorsNumber:
+.FAT12_L	EQU	#0000
+.FAT12_H	EQU	#07FA
+.FAT16_L	EQU	#0000
+.FAT16_H	EQU	#7FFA
+;
 FilesInRootDIR:
 .FDD_DD		EQU	112
 .FDD_HD		EQU	224
@@ -31,9 +42,9 @@ FAT_ReservedSectors:
 FAT_TYPES:	FAT_TYPES_LINE	#0800,		32768,		CONSTANTS.FAT32	; > 32768
 		FAT_TYPES_LINE	#0400,		16384,		CONSTANTS.FAT32	; 16384..32768 Mb
 		FAT_TYPES_LINE	#0200,		8192,		CONSTANTS.FAT32	;  8192..16384 Mb
-		FAT_TYPES_LINE	#0100,		4096,		CONSTANTS.FAT32	;  4096..8192 Mb
-		FAT_TYPES_LINE	#0080,		32768,		CONSTANTS.FAT16	;  2048..4096 Mb
-		FAT_TYPES_LINE	#0040,		16384,		CONSTANTS.FAT16	;  1023..2048 Mb
+		FAT_TYPES_LINE	#0080,		4096,		CONSTANTS.FAT32	;  2048..8192 Mb
+		FAT_TYPES_LINE	#0060,		32768,		CONSTANTS.FAT16	;  1536..2047 Mb
+		FAT_TYPES_LINE	#0040,		16384,		CONSTANTS.FAT16	;  1023..1535 Mb
 		FAT_TYPES_LINE	#0020,		8192,		CONSTANTS.FAT16	;   511..1023 Mb
 		FAT_TYPES_LINE	#0010,		4096,		CONSTANTS.FAT16	;   256..511 Mb
 		FAT_TYPES_LINE	#0008,		2048,		CONSTANTS.FAT16	;   128..256 Mb 
@@ -110,14 +121,14 @@ VARIABLES			EQU	$
 ;.Fat32_ReservedSectors		WORD	32
 .ReservedSectors		WORD	0				; [ ]
 .RootDirSectors			D24	0				; [ ]
-.NotUsedSpace			BYTE	0				; in sectors
+.NotUsedSpace			WORD	0		; in sectors	; [ ] неправильно считаются?
 .total_clusters_L:		WORD	0				; [x]
 .total_clusters_H:		WORD	0				; [x]
 .FAT32_RootDirClusters		WORD	1				; [ ]
 .FAT.LABEL			BYTE	'NO_LABEL   '			; [ ]
 .DriveExtendedParameters	BYTE	0				; [ ]
-.DataSectors_L			WORD	0				; [ ]
-.DataSectors_H			WORD	0				; [ ]
+.DataSectors_L			WORD	0				; [ ] неправильно считаются?
+.DataSectors_H			WORD	0				; [ ] неправильно считаются?
 .RootDirFirstSector_L		WORD	0				; [x] вычисляется в FORMAT_DRIVE
 .RootDirFirstSector_H		WORD	0				; [x] вычисляется в FORMAT_DRIVE
 .SectorsPerFAT_L		WORD	0				; [x]
diff --git a/ddf_build.txt b/ddf_build.txt
index f0b5c72..4b6f9c3 100644
--- a/ddf_build.txt
+++ b/ddf_build.txt
@@ -1 +1 @@
-57
\ No newline at end of file
+64
\ No newline at end of file
diff --git a/format.asm b/format.asm
index a10bc3c..e4dd7c8 100644
--- a/format.asm
+++ b/format.asm
@@ -322,12 +322,23 @@ STOP_ERROR:
 		LD	B,DSS_Error.sys.INVALID_FUNCTION
 		;!TODO
 
-EXIT:		PUSH	BC
+EXIT:		LD	C,Dss.Exit
+		PUSH	BC
 		LD	HL,Exit_Path
 		LD	C,Dss.ChDir
 		RST	ToDSS
 		;
-		LD	C,Dss.Exit
+		POP	BC
+		LD	A,B
+		AND	A
+		JP	Z,ToDSS
+		;
+		PUSH	BC
+		LD	HL,Error_Msg
+		LD	C,Dss.PChars
+		RST	ToDSS		
+		;
+		POP	BC
 		RST	ToDSS
 ;-----------------------------------------------------------------------
 
@@ -393,7 +404,7 @@ CALC_TOTAL_CLUSTERS:
 .skip_dec_DE:	; DE:HL = total_sectors - reserved_sectors
 .push_regs:	PUSH	DE
 		PUSH	HL
-		;num_fats * fat_sz32;	fat_sz32 в кластерах
+		;num_fats * fat_size;	fat_size в кластерах
 .fat_size_l+1:	LD	BC,0
 .fat_size_h+1:	LD	DE,0
 		LD	A,(FAT_PARAMETERS.Number_of_FATs)
@@ -403,7 +414,7 @@ CALC_TOTAL_CLUSTERS:
 		LD	C,L
 		PUSH	IX
 		POP	DE
-		;num_fats * fat_sz32 = BCDE
+		;num_fats * fat_size = BCDE
 		;
 		LD	HL,(VARIABLES.RootDirSectors)
 		ADD	HL,DE
@@ -413,7 +424,7 @@ CALC_TOTAL_CLUSTERS:
 		ADC	HL,BC
 		LD	B,H
 		LD	C,L
-		;num_fats * fat_sz32 + root_dir_sectors = BC:DE
+		;num_fats * fat_size + root_dir_sectors = BC:DE
 		;
 		POP	HL
 		SBC	HL,DE
@@ -421,15 +432,26 @@ CALC_TOTAL_CLUSTERS:
 		POP	HL
 		SBC	HL,BC
 		JP	C,STOP_ERROR
-	; data_sectors = HL:DE
+		; data_sectors = HL:DE	0x7FFA0000
+		;
+		;CALL	CHECK_MAX_DATA_SECTORS
+		JP	C,STOP_ERROR					; сменить FAT type?
+		;
 		LD	(VARIABLES.DataSectors_L),DE
 		LD	(VARIABLES.DataSectors_H),HL
+		;
 	; total_clusters
 		LD	A,(FAT_PARAMETERS.SectorsPerCluster)
 		CALL	HLDE_Div_A
-		LD	(VARIABLES.NotUsedSpace),A
-		; total_clusters = HL:DE
+		; total_clusters = HL:DE, A - unused space in sectors
 		;
+		LD	B,0
+		LD	C,A
+		LD	IX,(VARIABLES.NotUsedSpace)
+		ADD	IX,BC
+		JP	C,STOP_ERROR					; сменить FAT type?
+		;
+		LD	(VARIABLES.NotUsedSpace),IX
 		LD	(VARIABLES.total_clusters_L),DE
 		LD	(VARIABLES.total_clusters_H),HL
 	; fat_size
@@ -487,6 +509,79 @@ CALC_TOTAL_CLUSTERS:
 ;-----------------------------------------------------------------------
 
 
+;-----------------------------------------------------------------------
+ IFUSED CHECK_MAX_DATA_SECTORS
+; IN:	data_sectors = HL:DE
+; OUT:	CF=0 corrected data_sectors = HL:DE
+;	CF=1 слишком большая разница
+CHECK_MAX_DATA_SECTORS:
+		LD	BC,0
+		LD	(VARIABLES.NotUsedSpace),BC
+		LD	A,(VARIABLES.FAT_TYPE)
+		SUB	CONSTANTS.FAT12
+		RET	NC						; good sectors
+		;
+		PUSH	HL
+		PUSH	DE
+		;
+		LD	BC,CONSTANTS.MaxDataSectorsNumber.FAT12_H
+		JR	Z,.sectors_fat12
+		; sectors_fat16
+		LD	BC,CONSTANTS.MaxDataSectorsNumber.FAT16_H
+.sectors_fat12:	PUSH	BC
+		LD	BC,(FAT_PARAMETERS.BytesPerSector)
+		CALL	MUL32_POWER2
+		; A:HL:DE
+		;
+		POP	BC
+		AND	A
+		JR	NZ,.too_mutch
+		;
+		AND	A
+		SBC	HL,BC
+		JR	C,.good_sectors
+		;
+		JR	NZ,.get_clu
+		LD	A,D
+		OR	E
+		JR	Z,.good_sectors
+		;
+.get_clu:	PUSH	DE
+		POP	IX
+		PUSH	BC
+		LD	BC,(FAT_PARAMETERS.BytesPerSector)
+		CALL	HLIX_div_BC
+		POP	BC
+		; HLIX remainder DE
+		; по идее, DE = 0 тут
+		;
+		LD	A,H
+		OR	L
+		JR	NZ,.too_mutch
+		;
+		LD	(VARIABLES.NotUsedSpace),IX
+		LD	IX,0
+		LD	H,B
+		LD	L,C
+		LD	BC,(FAT_PARAMETERS.BytesPerSector)
+		CALL	HLIX_div_BC
+		PUSH	IX
+		POP	DE
+		POP	BC
+		POP	BC
+		AND	A
+		RET
+		;
+.good_sectors:	SCF
+.too_mutch:	POP	DE
+		POP	HL
+		CCF
+		RET
+		;
+ ENDIF
+;-----------------------------------------------------------------------
+
+
 ;-----------------------------------------------------------------------
 SET_RESERVED_AND_ROOTDIR:
 		LD	A,(VARIABLES.FAT_TYPE)
@@ -1043,31 +1138,56 @@ JP_HL:		EX	DE,HL
 ;-----------------------------------------------------------------------
 ;!FIXIT
 SHOW_FORMAT_PARAMETERS:
+	;.disk
 		LD	A,(VARIABLES.CurrentDrive)
 		ADD	'A'
 		LD	(PARAMS_MSG.disk),A
-		;
+	;.unused
+		LD	BC,(FAT_PARAMETERS.BytesPerSector)
+		LD	DE,(VARIABLES.NotUsedSpace)
+		LD	HL,0
+		CALL	MUL32_POWER2
+		LD	(PARAMS_MSG.unused),DE
+		LD	(PARAMS_MSG.unused + 2),HL
+	;.fullSize
+		LD	HL,(VARIABLES.VOLUME_SIZE_BYTES + 2)
+		EXX
+		LD	HL,(VARIABLES.VOLUME_SIZE_BYTES)
+		LD	A,(VARIABLES.VOLUME_SIZE_BYTES + 4)
+		LD	DE,PARAMS_MSG.fullSize
+		CALL	PRINT_5BYTES
+	;.dataSize
+		LD	HL,(VARIABLES.DataSectors_H)
+		LD	DE,(VARIABLES.DataSectors_L)
+		LD	BC,(FAT_PARAMETERS.BytesPerSector)
+		CALL	MUL32_POWER2
+		PUSH	DE
+		EXX
+		POP	HL
+		LD	DE,PARAMS_MSG.dataSize
+		CALL	PRINT_5BYTES		
+	;.Clusters
 		LD	HL,(VARIABLES.total_clusters_L)
 		LD	(PARAMS_MSG.Clusters),HL
 		LD	HL,(VARIABLES.total_clusters_H)
 		LD	(PARAMS_MSG.Clusters + 2),HL
-		;
+	;.Clu_size
 		LD	HL,(VARIABLES.ClusterSize)
 		LD	(PARAMS_MSG.Clu_size),HL
-		;
+	;.FATtxt
 		LD	HL,(FAT_PARAMETERS.ID_FAT+3)
 		LD	(PARAMS_MSG.FATtxt + 3),HL
-		;
+	;.Serial
 		LD	HL,(FAT_PARAMETERS.SERIAL_NUMBER_1)
-		LD	(PARAMS_MSG.Serial),HL
-		LD	HL,(FAT_PARAMETERS.SERIAL_NUMBER_2)
 		LD	(PARAMS_MSG.Serial + 2),HL
-		;
+		LD	HL,(FAT_PARAMETERS.SERIAL_NUMBER_2)
+		LD	(PARAMS_MSG.Serial),HL
+	;.LabelTxt
 		LD	HL,FAT_PARAMETERS.LABEL
 		LD	DE,PARAMS_MSG.LabelTxt
 		LD	BC,FAT_PARAMETERS.LABEL.Size
 		LDIR
-		;
+	;
 		LD	IY,PARAMS_MSG.ptr
 		CALL	printf#.str
 
@@ -1297,6 +1417,195 @@ PutHexNumb:	PUSH	AF
 ;-----------------------------------------------------------------------
 
 
+;-----------------------------------------------------------------------
+; A:HL':HL - число для перевода
+; DE - буфер для текстовой строки
+PRINT_5BYTES:	PUSH	DE
+		LD	IX,L40BIT.Str		; "00"
+		LD	C,#17
+		EXX
+		LD	DE,#4876
+		EXX
+		LD	DE,#E800
+		; C:DE':DE =  100,000,000,000
+		CALL	GET_BIG_DIG
+		LD	C,#02
+		EXX
+		LD	DE,#540B
+		EXX
+		LD	DE,#E400
+		; C:DE':DE =  10,000,000,000
+		CALL	GET_BIG_DIG
+		LD	C,#00
+		EXX
+		LD	DE,#3B9A
+		EXX
+		LD	DE,#CA00
+		; C:DE':DE =  1,000,000,000
+		CALL	GET_BIG_DIG
+		; DE':DE =  100,000,000
+		CALL	.skip_1
+		POP	DE
+		;LD	DE,SIZE_BUFFER.high	; "0 000 000 000"
+		LD	HL,L40BIT.Str		; "0000000000"
+		LDI
+		LDI
+		LD	A,(HL)
+		LDI
+		CP	" "
+		JR	Z,1F
+		;
+		LD	A,","			; разд. разрядов
+1:		LD	(DE),A
+		INC	DE
+		LDI
+		LDI
+		LD	A,(HL)
+		LDI
+		CP	" "
+		JR	Z,1F
+		;
+		LD	A,","			; разд. разрядов
+1:		LD	(DE),A
+		INC	DE
+		LDI
+		LDI
+		LD	A,(HL)
+		LDI
+		CP	" "
+		JR	Z,1F
+		;
+		LD	A,","			; разд. разрядов
+1:		LD	(DE),A
+		INC	DE
+		LDI
+		LDI
+		LDI
+		;SCF
+		RET
+		;
+.skip_1:	EXX
+		LD	DE,#05F5
+		EXX
+		LD	DE,#E100
+		; DE':DE =  100,000,000
+		CALL	GET_DIG			; 100,000,000...999,999,999
+		EXX
+		LD	DE,#98
+		EXX
+		LD	DE,#9680
+		; DE':DE =  10,000,000
+		CALL	GET_DIG			; 10,000,000...99,999,999
+		EXX
+		LD	DE,#0F
+		EXX
+		LD	DE,#4240
+		; DE':DE =  1,000,000
+		CALL	GET_DIG			; 1,000,000...9,999,999
+		EXX
+		LD	DE,#01
+		EXX
+		LD	DE,#86A0
+		; DE':DE =  100,000
+		CALL	GET_DIG			; 100,000...999,999
+		EXX
+		LD	DE,#00
+		EXX
+		LD	DE,#2710
+		; DE':DE =  10,000
+		CALL	GET_DIG			; 10,000...99,999
+		EXX
+		LD	DE,#00
+		EXX
+		LD	DE,#03E8
+		; DE':DE =  1,000
+		CALL	GET_DIG			; 1,000...9,999
+		EXX
+		LD	DE,#00
+		EXX
+		LD	DE,#64
+		; DE':DE =  100
+		CALL	GET_DIG			; 100..999
+		EXX
+		LD	DE,#00
+		EXX
+		LD	DE,#0A
+		; DE':DE =  10
+		CALL	GET_DIG			; 10..99
+		LD	A,L
+		ADD	A,"0"
+		LD	(ix+0),A
+		INC	IX
+		RET
+		;
+GET_DIG:	LD	A,"0"-1
+		AND	A
+.loop:		INC	A
+		SBC	HL,DE
+		EXX
+		SBC	HL,DE
+		EXX
+		JR	NC,.loop
+		;
+		ADD	HL,DE
+		EXX
+		ADC	HL,DE
+		EXX
+		CP	"0"
+		JR	NZ,.putChar
+		;
+		LD	B,A
+		LD	A,(ix-1)
+		CP	" "
+		JR	Z,.putChar
+		;
+		LD	A,B
+.putChar:	LD	(ix+0),A
+		INC	IX
+		RET
+		;
+GET_BIG_DIG:	LD	B,"0"-1
+		AND	A
+.loop:		INC	B
+		SBC	HL,DE
+		EXX
+		SBC	HL,DE
+		EXX
+		SBC	A,C
+		JR	NC,.loop
+		;
+		ADD	HL,DE
+		EXX
+		ADC	HL,DE
+		EXX
+		ADC	A,C
+		EX	AF,AF'
+		LD	A,B
+		CP	"0"
+		JR	NZ,.putChar
+		;
+		LD	A,(ix-1)
+		CP	" "
+		JR	Z,.putChar
+		;
+		LD	A,B
+.putChar:	LD	(ix+0),A
+		EX	AF,AF'
+		INC	IX
+		RET
+		;
+L40BIT:		DB	" "		; маркер для ix-1 
+.Str:		DB	"  "		; 00
+L32BIT_:	DB	"         "	; 000000000
+.end:		DB	"0"
+		;
+; SIZE_BUFFER:	db	" "			; маркер для ix-1 
+; .high		db	"  "			; "00"
+; .low:		db	"             ",0,0	; "0 000 000 000",0,0
+; .bytes		equ	SIZE_BUFFER - $
+;-----------------------------------------------------------------------
+
+
 ////////////////////////////////////////////////////////////////////////
 	include 'math.asm'
 ////////////////////////////////////////////////////////////////////////
diff --git a/math.asm b/math.asm
index fdb72ab..77683fb 100644
--- a/math.asm
+++ b/math.asm
@@ -127,7 +127,6 @@ HLIX_div_BC:	EX	DE,HL
 ;-----------------------------------------------------------------------
 ; ->	HLDE * BC. BC = степень двойки
 ; <-	AHLDE
-;	CF=1 - error
 MUL32_POWER2:	SRL	B
 		RR	C
 		LD	A,B
@@ -140,7 +139,7 @@ MUL32_POWER2:	SRL	B
 		EX	DE,HL
 		ADC	HL,HL
 		ADC	A,0
-		JP	C,STOP_ERROR
+		JP	C,STOP_ERROR					; CF=1 - error
 		;
 		SRL	B
 		RR	C