Documentation: | Census 1970 on 2010 Geographies |
Document: | 1970 Census Users' Guide - Part II |
citation: | Social Explorer; U.S. Census Bureau; 1970 Census Users’ Guide; U. S. Government Printing Office, Washington, D. C., 1970. |
Example 1. Suppression Codes on Summary Tapes | ||||
---|---|---|---|---|
Data Field Size in Characters | Type of Suppression | Possible Codes in First Item in Tabulation or Sub-Tabulation | Second Itme in Tabulation or Sub-Tabulation | Remainder of Tabulation or Sub-Tabulation, inf any |
6 | 1 | -00001 | Blanks | Blanks |
6 | 2 | -00002 | Total(xxxxxx) | Blanks |
8 | 1 | -0000001 | Blanks | Blanks |
8 | 2 | -0000002 | Total(xxxxxxxx) | Blanks |
12 | 1 | -00000000001 | Blanks | Blanks |
12 | 2 | -00000000002 | Total(xxxxxxxxxxxx) | Blanks |
16 | 1 | -000000000000001 | Blanks | Blanks |
16 | 2 | -000000000000002 | Total(xxxxxxxxxxxxxxxx) | Blanks |
Suppression Indicator | Explanation |
---|---|
SX | If this indicator appeared in the documentation of a tabulation, none of its data items would ever be suppressed. If the table in Example 2 had this indicator, all 210 items would always have numeric totals for the defined groupings. |
SA | If this indicator appeared, each of the data items in the tabulation would have to be checked for possible replacement by the negative numeric suppression code, -0 ... 01. (If suppression occurred, it would only be type one. ) If Example 2 had an SA indicator, each of the 210 data items would have to be checked. |
S0 | If this indicator appeared, only the first item in the tabulation would have to be checked for suppression codes. If the first item has the -0 ... 01 code, the rest of the tabulation will be blanks. A -0...02 code specifies that the second item will contain the sum total of the suppressed tabulation and all other items will be blank. If Example 2 had an S0 code, the first item, e.g., Total Males 14-19 Years Now Married, would be the only item with a possible suppression code. |
S1 | If this indicator appeared in the tabulation documentation, each initial item in the primary stratifications would have to be checked for a suppression code. If present, all of the data for that primary-level distribution would be suppressed independently of the other distributions. In Example 2, there are three primary stratifications: Total, White, and Negro. The three items which may contain suppression codes are item 1 (Total Males 14-19 Years Now Married), item 71 (White Males 14-19 Years Now Married), and item 141 (Negro Males 14-19 Years Now Married). |
S2 | If this indicator appeared for the table, all initial items in primary and secondary stratifications need to be checked for possible suppression codes. Only those items following in the level of stratification which starts with a suppression code will be suppressed. With reference to Example 2, if this code appeared, the following six fields would have to be checked for suppression indicators: |
Total Males 14-19 Years Now Married Total Females 14-19 Years Now Married White Males 14-19 Years Now Married White Females 14-19 Years Now Married Negro Males 14-19 Years Now Married Negro Females 14-19 Years Now Married | |
The rest of the items in a suppressed distribution will be blanked. |
Population 14 Years Old and Over by Marital Status, Age, Race, and Sex | No. of data Items |
---|---|
210 (x)1 | |
Count of Persons 14 and Over | |
By: Race (3) By: Sex (2) By: Age (7) By: Marital Status (5). | |
Total: | |
Male: | |
14-19 Years: | |
Now Married (excludes separated) | |
Widowed | |
Divorced | |
Separated | |
Never Married | |
20-24: | |
Repeat Marital Status (5) | |
25-34: | |
Repeat Marital Status (5) | |
35-44: | |
Repeat Marital Status (5) | |
45-54: | |
Repeat Marital Status (5) | |
55-64: | |
Repeat Marital Status (5) | |
65 years and over: | |
Repeat Marital Status (5) | |
Female: | |
Same as Male (35) | |
White: | |
Same as Total (70) | |
Negro: | |
Same as Total (70) |
Type Label | Required | Optional continuation |
---|---|---|
Volume (reel): | ||
header | VOL1 | (none) |
trailer | EOV1 | EOV2 thru 9 |
File: | ||
header | HDR1 | HDR thru 9 |
trailer | EOF1 | EOF2 thru 9 |
Technical Characteristics of Magnetic Tape Recording for 1970 Census Summary Tapes | ||
---|---|---|
Characteristics | Industry Compatible Tape | |
7-Track Tape | 9-Track Tape | |
Width | .5 inch | .5 inch |
Reel Size | 10.5 inch diameter; maximum 2400 foot length | 10.5 inch diameter; maximum 2400 foot length |
Recording Mode | NRZI (nonreturn to zero) | NRZI (nonreturn to zero) |
Number of Recording Tracks | 7 (9 data, 1 parity) | 9 (8 data, 1 parity) |
Density (characters or bytes per inch) | 556/800 | 800 |
Language | Binary Coded Decimal (BCD) | Extended Binary Coded Decimal Interchange Code (EBCDIC) USA Standard Code for Information Interchange (USASCII or ASCII) |
Error Controls | Character - even parity Track - longituinal redundancy check | Character (byte) - odd parity Block-Cyclical code check based on an 8-bit character which is computed during write operation and recorded at end of tape block as hardware function |
Recorded Tape Representation | One 6-bit character per tape frame | One 8-bit character per tape frame |
Interblock Spacing | .75 inch | .6 inch (nominal) |
Technical Characteristics of Magnetic Tape Recording for 1970 Census Summary Tapes | ||
---|---|---|
Characteristics | Industry Compatible Tape | |
7-Track Tape | 9-Track Tape | |
Width | .5 inch | .5 inch |
Reel Size | 10.5 inch diameter; maximum 2400 foot length | 10.5 inch diameter; maximum 2400 foot length |
Recording Mode | NRZI (nonreturn to zero) | NRZI (nonreturn to zero) |
Number of Recording Tracks | 7 (9 data, 1 parity) | 9 (8 data, 1 parity) |
Density (characters or bytes per inch) | 556/800 | 800 |
Language | Binary Coded Decimal (BCD) | Extended Binary Coded Decimal Interchange Code (EBCDIC) USA Standard Code for Information Interchange (USASCII or ASCII) |
Error Controls | Character - even parity Track - longituinal redundancy check | Character (byte) - odd parity Block-Cyclical code check based on an 8-bit character which is computed during write operation and recorded at end of tape block as hardware function |
Recorded Tape Representation | One 6-bit character per tape frame | One 8-bit character per tape frame |
Interblock Spacing | .75 inch | .6 inch (nominal) |
Volume Header Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "VOL" |
2 | Label Number | 1 | "1" |
31 | Tape Physical Number | 6 | Six alphanumeric characters assigned to identify the physical reel of tape; should agree with external visual identification. Must be 6 characters other than blank. |
4 | Accessibility | 1 | Space: unlimited access. |
5 | Reserved for Operating System | 20 | System creating tape may use this space. |
6 | Reserved for Future | 6 | Spaces |
7 | Owner Identification | 14 | Spaces |
8 | Reserved for Future | 28 | Spaces |
9 | Label Standard Level | 1 | Space: label and data format on this volume require the agreement of interchange parties. |
-Inter-record gap- |
First File Header Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "HDR" |
2 | Label Number | 1 | "1" |
31 | Tape Physical Number | 17 | Alphanumeric unique name for file. This field is recorder as follows: eight characters, the first of which must be a letter, with the remaining seven wither letters or numbers followed by nine spaces. Example: ST35X1ST |
4 | Set Identification | 6 | Alphanumeric unique name for set of files of which this file is part. Must be the same in all files of a multifile set. Must be present for single file set. Example: CT1A70. |
5 | File Section Number | 4 | Must be numeric. On the first volume a file appears on, this will be "0001". This will be augmented by 1 for each additional volume on which a file appears. |
6 | File Sequence Number | 4 | Numeric. Denotes the sequence (i.e., 001,002, etc.) of files within the volume. In all the labels of this type for a given file, this field will contain the same number. |
7 | Generation Number | 4 | Spaces |
8 | Generation Version Number | 2 | Spaces |
9 | Creation Date | 6 | A space, followed by two numeric characters for the year, followed by three numeric characters for the day within the year. Example: |
10 | Expiration Date | 6 | Same format as Field 9. Will be entered as " |
11 | Accessibility | 1 | Space: unlimited access. |
12 | Block Count | 6 | "000000" |
13 | System Code | 13 | Alphanumeric identification for the operating system that produces the file, supplied by Census in the following format: "CENSUS x CI Uy" where x = machine identification (A, B, C, or D) y= tape unit identification ( |
14 | Reserved for Future Standardization | 7 | Spaces |
-Inter-record gap- |
Second File Header Lable | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "HDR" |
2 | Label Number | 1 | "2" |
3 | Record format | 1 | "F": fixed length. |
4 | Block Length (Physical record) | 5 | "01800" (example only; some multiple of 120 between 720 and 2040). |
5 | Record Length2 | 5 | "01800" (example only; some multiple of 120, no larger than the block length in Field 4). |
6 | Recording Density | 1 | "1": 556"2": 800 |
7 | File Position | 1 | Identifies condition that caused creation of label. "0": if HDR and OPEN; if trailer and CLOSE. "1": if created bacesaue of EOV. |
8 | Job/Step ID | 17 | Spaces |
9 | Tape Recording | 2 | "ET": even parity (7-track tape only)." |
10 | Printer Control | 1 | Space: no control characters. |
11 | Reserved for Operating System | 43 | Spaces |
-Tape Mark- | |||
Data | |||
-Tape Mark- | |||
(Data and tape mark are followed by either the two End-of-File labels or the two End-of-Volume labels shown here. Also see section on Groups of labels). |
First End-of-File Trailer Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "EOF" |
2 | Label Number | 1 | "1" |
3-11 | Same as corresponding fields in HDR1 | ||
12 | Block Count | 6 | Numeric. Number of data blocks (exclusive of labels and tape marks) since the preceding HDR label group. |
13-14 | Same as corresponding fields in HDR1 | ||
-Inter-record gap- |
Second End-of-File Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "EOF" |
2 | Label Number | 1 | "2" |
3-11 | Same as corresponding fields in HDR2 |
First End-of-Volume Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "EOV" |
2 | Label Number | 1 | "1" |
3-11 | Same as corresponding fields in HDR1 of current file | ||
12 | Block Count | 6 | Numeric. Number of data blocks since the preceding HDR label group. |
13-14 | Same as corresponding fields in HDR1 | ||
-Inter-record gap- |
Second End-of-Volume Label | |||
---|---|---|---|
Field | Name | Field Length in Characters | Description |
1 | Label Identifier | 3 | "EOV" |
2 | Label Number | 1 | "2" |
3-11 | Same as corresponding fields in HDR2 |
Character Conversion Chart | |||
---|---|---|---|
Conversion Code for 43 Characters in ACSCII, BCD, and EBCDIC | |||
Character graphic | ASCII | BCD1(octal)3 | EBCDIC2(hexadecimal)4 |
blank (space) | 20 | 205 | 40 |
- (minus) | 2D | 40 | 60 |
0 | 30 | 12 | F0 |
1 | 31 | 01 | F1 |
2 | 32 | 02 | F2 |
3 | 33 | 03 | F3 |
4 | 34 | 04 | F4 |
5 | 35 | 05 | F5 |
6 | 36 | 06 | F6 |
7 | 37 | 07 | F7 |
8 | 38 | 10 | F8 |
9 | 39 | 11 | F9 |
, (comma) | 2C | 33 | 6B |
. (period) | 2E | 73 | 4B |
A | 41 | 61 | C1 |
B | 42 | 62 | C2 |
C | 43 | 63 | C3 |
D | 44 | 64 | C4 |
E | 45 | 65 | C5 |
F | 46 | 66 | C6 |
G | 47 | 67 | C7 |
H | 48 | 70 | C8 |
I | 49 | 71 | C9 |
J | 4A | 41 | D1 |
K | 4B | 42 | D2 |
L | 4C | 43 | D3 |
M | 4D | 44 | D4 |
N | 4E | 45 | D5 |
O | 4F | 46 | D6 |
P | 50 | 47 | D7 |
Q | 51 | 50 | D8 |
R | 52 | 51 | D9 |
S | 53 | 22 | E2 |
T | 54 | 23 | E3 |
U | 55 | 24 | E4 |
V | 56 | 25 | E5 |
W | 57 | 26 | E6 |
X | 58 | 27 | E7 |
Y | 59 | 30 | E8 |
Z | 5A | 31 | E9 |
$ (dollar) | 24 | 53 | 5B |
* (asterisk) | 2A | 54 | 5C |
(slash or virgule) | 2F | 21 | 61 |