CDC display code

Display code is the six-bit character code used by many computer systems manufactured by Control Data Corporation, notably the CDC 6000 series in 1964, the 7600 in 1967 and the following Cyber series in 1971. The CDC 6000 series and their successors had 60 bit words. As such, typical usage packed 10 characters per word. It is a six-bit extension of the four-bit BCD encoding, and was referred to as BCDIC[citation needed] (BCD interchange code.)

Overview

There were several variations of display code, notably the 63-character character set, and the 64-character character set. There were also 'CDC graphic' and 'ASCII graphic' variants of both the 63- and 64-character sets. The choice between 63- or 64-character character set, and between CDC or ASCII graphic was site-selectable. Generally, early CDC customers started out with the 63-character character set, and CDC graphic print trains on their line printers. As time-sharing became prevalent, almost all sites used the ASCII variant - so that line printer output would match interactive usage. Later CDC customers were also more likely to use the 64-character character set.

A later variation, called 6/12 display code, was used in the Kronos and NOS timesharing systems in order to support full ASCII capabilities. In 6/12 mode, an escape character (the circumflex, octal 76) would indicate that the following letter was lower case. Thus, upper case and other characters were 6 bits in length, and lower case characters were 12 bits in length.

The PLATO system used a further variant of 6/12 display code. Noting that lower case letters were most common in typical PLATO usage, the roles were reversed. Lower case letters were the norm, and the escape character preceded upper case letters.

The typical text file format used a zero-byte terminator to signify the end of each record. The zero-byte terminator was indicated by, at least, the final twelve bits of a 60-bit word being set to zero. The terminator could actually be anywhere from 12- to 66-bits long - depending on the length of the record. This caused an ambiguity in the 64-character character set, when a colon character needed to be the final character in a record. In such cases a blank character was typically appended to the record after the trailing colon.

Display code characters

64-character character set version

			ASCII	CDC
ASCIICDC BinaryDecimalOctalGraphicGraphicName 000 000000::colon 000 001101AA 000 010202BB 000 011303CC 000 100404DD 000 101505EE 000 110606FF 000 111707GG 001 000810HH 001 001911II 001 0101012JJ 001 0111113KK 001 1001214LL 001 1011315MM 001 1101416NN 001 1111517OO 010 0001620PP 010 0011721QQ 010 0101822RR 010 0111923SS 010 1002024TT 010 1012125UU 010 1102226VV 010 1112327WW 011 0002430XX 011 0012531YY 011 0102632ZZ 011 011273300 011 100283411 011 101293522 011 110303633 011 111313744	ASCIICDC BinaryDecimalOctalGraphicGraphicName 100 000324055 100 001334166 100 010344277 100 011354388 100 100364499 100 1013745++ 100 1103846-- 100 1113947** 101 0004050// 101 0014151(( 101 0104252)) 101 0114353$$ 101 1004454== 101 1014555blank 101 1104656,, 101 1114757.. 110 0004860#≡equiv 110 0014961[[ 110 0105062]] 110 0115163%% 110 1005264"≠not eq 110 1015365_→concat 110 1105466!∨log OR 110 1115567&∧log AND 111 0005670'↑super 111 0015771?↓sub 111 0105872<< 111 0115973>> 111 1006074@≤ 111 1016175\≥ 111 1106276^¬NOT 111 1116377;;
Binary	Decimal	Octal	Graphic	Graphic	Name
000 000	0	00	:	:	colon
000 001	1	01	A	A
000 010	2	02	B	B
000 011	3	03	C	C
000 100	4	04	D	D
000 101	5	05	E	E
000 110	6	06	F	F
000 111	7	07	G	G
001 000	8	10	H	H
001 001	9	11	I	I
001 010	10	12	J	J
001 011	11	13	K	K
001 100	12	14	L	L
001 101	13	15	M	M
001 110	14	16	N	N
001 111	15	17	O	O
010 000	16	20	P	P
010 001	17	21	Q	Q
010 010	18	22	R	R
010 011	19	23	S	S
010 100	20	24	T	T
010 101	21	25	U	U
010 110	22	26	V	V
010 111	23	27	W	W
011 000	24	30	X	X
011 001	25	31	Y	Y
011 010	26	32	Z	Z
011 011	27	33	0	0
011 100	28	34	1	1
011 101	29	35	2	2
011 110	30	36	3	3
011 111	31	37	4	4
			ASCII	CDC
Binary	Decimal	Octal	Graphic	Graphic	Name
100 000	32	40	5	5
100 001	33	41	6	6
100 010	34	42	7	7
100 011	35	43	8	8
100 100	36	44	9	9
100 101	37	45	+	+
100 110	38	46	-	-
100 111	39	47	*	*
101 000	40	50	/	/
101 001	41	51	(	(
101 010	42	52	)	)
101 011	43	53	$	$
101 100	44	54	=	=
101 101	45	55			blank
101 110	46	56	,	,
101 111	47	57	.	.
110 000	48	60	#	≡	equiv
110 001	49	61	[	[
110 010	50	62	]	]
110 011	51	63	%	%
110 100	52	64	"	≠	not eq
110 101	53	65	_	→	concat
110 110	54	66	!	∨	log OR
110 111	55	67	&	∧	log AND
111 000	56	70	'	↑	super
111 001	57	71	?	↓	sub
111 010	58	72	<	<
111 011	59	73	>	>
111 100	60	74	@	≤
111 101	61	75	\	≥
111 110	62	76	^	¬	NOT
111 111	63	77	;	;

6/12 display code

The NOS 6/12 display code is one of the character sets used on CDC Cyber NOS computers to represent all ASCII characters.

ASCII	display code
ASCIIdisplay code DecHexAbbrDecOct6/12 000NUL62 3276 40^5 101SOH62 3376 41^6 202STX62 3476 42^7 303ETX62 3576 43^8 404EOT62 3676 44^9 505ENQ62 3776 45^+ 606ACK62 3876 46^- 707BEL62 3976 47^* 808BS62 4076 50^/ 909HT62 4176 51^( 100ALF62 4276 52^) 110BVT62 4376 53^$ 120CFF62 4476 54^= 130DCR62 4576 55^ 140ESO62 4676 56^, 150FSI62 4776 57^. 1610DLE62 4876 60^# 1711DC162 4976 61^[ 1812DC262 5076 62^] 1913DC362 5176 63^% 2014DC462 5276 64^" 2115NAK62 5376 65^_ 2216SYN62 5476 66^! 2317ETB62 5576 67^& 2418CAN62 5676 70^' 2519EM62 5776 71^? 261ASUB62 5876 72^< 271BESC62 5976 73^> 281CFS62 6076 74^@ 291DGS62 6176 75^\ 301ERS62 6276 76^^ 311FUS62 6376 77^;	ASCIIdisplay code DecHexGlyphDecOct6/12 32204555 3321!5466! 3422"5264" 3523#4860# 3624$4353$ 3725%5163% 3826&5567& 3927'5670' 4028(4151( 4129)4252) 422A3947 432B+3745+ 442C,4656, 452D-3846- 462E.4757. 472F/4050/ 4830027330 4931128341 5032229352 5133330363 5234431374 5335532405 5436633416 5537734427 5638835438 5739936449 583A:60 474 04@D 593B;6377; 603C<5872< 613D=4454= 623E>5973> 633F?5771?
Dec	Hex	Abbr	Dec	Oct	6/12
0	00	NUL	62 32	76 40	^5
1	01	SOH	62 33	76 41	^6
2	02	STX	62 34	76 42	^7
3	03	ETX	62 35	76 43	^8
4	04	EOT	62 36	76 44	^9
5	05	ENQ	62 37	76 45	^+
6	06	ACK	62 38	76 46	^-
7	07	BEL	62 39	76 47	^*
8	08	BS	62 40	76 50	^/
9	09	HT	62 41	76 51	^(
10	0A	LF	62 42	76 52	^)
11	0B	VT	62 43	76 53	^$
12	0C	FF	62 44	76 54	^=
13	0D	CR	62 45	76 55	^
14	0E	SO	62 46	76 56	^,
15	0F	SI	62 47	76 57	^.
16	10	DLE	62 48	76 60	^#
17	11	DC1	62 49	76 61	^[
18	12	DC2	62 50	76 62	^]
19	13	DC3	62 51	76 63	^%
20	14	DC4	62 52	76 64	^"
21	15	NAK	62 53	76 65	^_
22	16	SYN	62 54	76 66	^!
23	17	ETB	62 55	76 67	^&
24	18	CAN	62 56	76 70	^'
25	19	EM	62 57	76 71	^?
26	1A	SUB	62 58	76 72	^<
27	1B	ESC	62 59	76 73	^>
28	1C	FS	62 60	76 74	^@
29	1D	GS	62 61	76 75	^\
30	1E	RS	62 62	76 76	^^
31	1F	US	62 63	76 77	^;
ASCII	display code
Dec	Hex	Glyph	Dec	Oct	6/12
32	20		45	55
33	21	!	54	66	!
34	22	"	52	64	"
35	23	#	48	60	#
36	24	$	43	53	$
37	25	%	51	63	%
38	26	&	55	67	&
39	27	'	56	70	'
40	28	(	41	51	(
41	29	)	42	52	)
42	2A	*	39	47	*
43	2B	+	37	45	+
44	2C	,	46	56	,
45	2D	-	38	46	-
46	2E	.	47	57	.
47	2F	/	40	50	/
48	30	0	27	33	0
49	31	1	28	34	1
50	32	2	29	35	2
51	33	3	30	36	3
52	34	4	31	37	4
53	35	5	32	40	5
54	36	6	33	41	6
55	37	7	34	42	7
56	38	8	35	43	8
57	39	9	36	44	9
58	3A	:	60 4	74 04	@D
59	3B	;	63	77	;
60	3C	<	58	72	<
61	3D	=	44	54	=
62	3E	>	59	73	>
63	3F	?	57	71	?

ASCII	display code
ASCIIdisplay code DecHexGlyphDecOct6/12 6440@60 174 01@A 6541A101A 6642B202B 6743C303C 6844D404D 6945E505E 7046F606F 7147G707G 7248H810H 7349I911I 744AJ1012J 754BK1113K 764CL1214L 774DM1315M 784EN1416N 794FO1517O 8050P1620P 8151Q1721Q 8252R1822R 8353S1923S 8454T2024T 8555U2125U 8656V2226V 8757W2327W 8858X2430X 8959Y2531Y 905AZ2632Z 915B[4961[ 925C\6175\ 935D]5062] 945E^60 274 02@B 955F_5365_	ASCIIdisplay code DecHexGlyphDecOct6/12 9660'60 774 07@G 9761a62 176 01^A 9862b62 276 02^B 9963c62 376 03^C 10064d62 476 04^D 10165e62 576 05^E 10266f62 676 06^F 10367g62 776 07^G 10468h62 876 10^H 10569i62 976 11^I 1066Aj62 1076 12^J 1076Bk62 1176 13^K 1086Cl62 1276 14^L 1096Dm62 1376 15^M 1106En62 1476 16^N 1116Fo62 1576 17^O 11270p62 1676 20^P 11371q62 1776 21^Q 11472r62 1876 22^R 11573s62 1976 23^S 11674t62 2076 24^T 11775u62 2176 25^U 11876v62 2276 26^V 11977w62 2376 27^W 12078x62 2476 30^X 12179y62 2576 31^Y 1227Az62 2676 32^Z 1237B{62 2776 33^0 1247C\|62 2876 34^1 1257D}62 2976 35^2 1267E~62 3076 36^3 1277FDEL62 3176 37^4
Dec	Hex	Glyph	Dec	Oct	6/12
64	40	@	60 1	74 01	@A
65	41	A	1	01	A
66	42	B	2	02	B
67	43	C	3	03	C
68	44	D	4	04	D
69	45	E	5	05	E
70	46	F	6	06	F
71	47	G	7	07	G
72	48	H	8	10	H
73	49	I	9	11	I
74	4A	J	10	12	J
75	4B	K	11	13	K
76	4C	L	12	14	L
77	4D	M	13	15	M
78	4E	N	14	16	N
79	4F	O	15	17	O
80	50	P	16	20	P
81	51	Q	17	21	Q
82	52	R	18	22	R
83	53	S	19	23	S
84	54	T	20	24	T
85	55	U	21	25	U
86	56	V	22	26	V
87	57	W	23	27	W
88	58	X	24	30	X
89	59	Y	25	31	Y
90	5A	Z	26	32	Z
91	5B	[	49	61	[
92	5C	\	61	75	\
93	5D	]	50	62	]
94	5E	^	60 2	74 02	@B
95	5F	_	53	65	_
ASCII	display code
Dec	Hex	Glyph	Dec	Oct	6/12
96	60	'	60 7	74 07	@G
97	61	a	62 1	76 01	^A
98	62	b	62 2	76 02	^B
99	63	c	62 3	76 03	^C
100	64	d	62 4	76 04	^D
101	65	e	62 5	76 05	^E
102	66	f	62 6	76 06	^F
103	67	g	62 7	76 07	^G
104	68	h	62 8	76 10	^H
105	69	i	62 9	76 11	^I
106	6A	j	62 10	76 12	^J
107	6B	k	62 11	76 13	^K
108	6C	l	62 12	76 14	^L
109	6D	m	62 13	76 15	^M
110	6E	n	62 14	76 16	^N
111	6F	o	62 15	76 17	^O
112	70	p	62 16	76 20	^P
113	71	q	62 17	76 21	^Q
114	72	r	62 18	76 22	^R
115	73	s	62 19	76 23	^S
116	74	t	62 20	76 24	^T
117	75	u	62 21	76 25	^U
118	76	v	62 22	76 26	^V
119	77	w	62 23	76 27	^W
120	78	x	62 24	76 30	^X
121	79	y	62 25	76 31	^Y
122	7A	z	62 26	76 32	^Z
123	7B	{	62 27	76 33	^0
124	7C	\|	62 28	76 34	^1
125	7D	}	62 29	76 35	^2
126	7E	~	62 30	76 36	^3
127	7F	DEL	62 31	76 37	^4

External links

Savard, John J. G. (2018) [2005]. . quadibloc. The Early Days of Hexadecimal. from the original on 2018-07-16.

Francois Pinard (1999-04-27). . Archived from on 2011-06-23.