April 21, 1998
1990 Census of Population and Housing
Summary Tape File 3A
CD90-3A-18
Illinois (Madison-Woodford)
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We recently discovered that we had omitted updates of selected fields on 
CD90-3A-18 containing data for Illinois (Madison-Woodford).  This CD-ROM
contains updates in the following database files.
	
	STF312IL.DBF
	STF313IL.DBF
	STF314IL.DBF
	STF315IL.DBF
	STF321IL.DBF
	STF322IL.DBF
	STF326IL.DBF
	STF333IL.DBF

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Using the CD-ROM

This CD-ROM includes both DOS and WINDOWS data retrieval software. 

For direct access to the data files, one of the many software packages
which recognize the dBASE III (.DBF) format will be very useful.

Users of other types of systems, such as the Apple Macintosh, have access
to the files through support for ISO 9660 CD-ROMs.

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For Windows 3.1 Users

	From Program Manager, select "Run" from the "File" menu and type 
	D:\WINSTALL\SETUP.EXE where D is your CD-ROM drive and press <Enter>.

For Windows 95 Users

	Select "Run" from the "Start" button and type D:\WINSTALL\SETUP.EXE 
	where D is your CD-ROM drive and press <Enter>.

All Windows Users

	Complete installation by executing the "BDE Configuration Utility" and
	and setting the MAXFILEHANDLES to 100 on the system page.

	Follow the instructions as they are displayed.  When finished, an
	application icon group will appear.  Start the software by
	double-clicking on the CD-ROM icon.

	Refer to \DOCUMENT\SOFTWARE.ASC for information about the Windows software.

Questions

	Contact Tech Support at 301-457-1324 or e-mail teschsupp@census.gov

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For DOS Users


	Type GO at the DOS prompt and ENTER.  
                
	For LAN installation, type GO LAN (slightly slower performance).
                

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Some States Span Multiple CD-ROMs

Some STF 3A State files require more than one CD-ROM.  When a State is split,
each CD-ROM contains small area summaries such as census tracts and block
groups for selected counties.  Each of the CD-ROMs for a State contains all
summaries for places, counties, and higher levels of census geography.

The software displays some brief statistical definitions through the glossary
function.  Refer to Appendix B (\document\append_b.asc) of the technical 
documentation for the complete text.

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Converting dBase Files to ASCII Text

'----------------------------------------------------------------------------
'The following is a Microsoft BASIC program that converts a dBASE (.DBF) 
'file to an ASCII (.TXT) file.  Users without database management software 
'who wish to convert the dBASE files to ASCII can follow this example.
'----------------------------------------------------------------------------
'Review data dictionaries in the technical documentation on the CD-ROM; 
'geographic fields at the front of each data file are described in the How 
'to Read Data Dictionaries file.
'----------------------------------------------------------------------------
CLS
INPUT "Database file to convert -> ", InFile$
INPUT "               Text file -> ", OuFile$
OPEN InFile$ FOR BINARY AS #1
OPEN OuFile$ FOR OUTPUT AS #2
TYPE HdrStru
        Filler AS STRING * 4
        RecCount AS LONG
        HdrBytes AS INTEGER
        RecBytes AS INTEGER
END TYPE
DIM Hdr AS HdrStru
GET #1, , Hdr
SEEK #1, Hdr.HdrBytes + 1
RecCntr = 0
DO
        Rec$ = STRING$(Hdr.RecBytes, " ")
        GET #1, , Rec$
        PRINT #2, MID$(Rec$, 2)
        RecCntr = RecCntr + 1
        IF RecCntr = Hdr.RecCount THEN EXIT DO
LOOP
CLOSE #1, #2

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Contents of the CD-ROM

Volume in drive is CD90_3A_nn

DOCUMENT <DIR> Directory for documentation files.  These are ASCII text files
               which contain complete technical documentation for the data.
               See \DOCUMENT\HOWTOUSE.ASC for information on the contents of
               the files.

GO.BAT         Batch file to execute data retrieval software.

STF3A.EXE      Data retrieval software.

STF3??ss.DBF   Statistical database files for each State. <ss> is the State
               abbreviation.  There are 35 files for each State numbered
               STF300ss.DBF through STF334ss.DBF

>>Reference Files<<
STF3STRU.DBF   This file describes the structure of the first 67 fields in the
               statistical database file.  These are the identification fields.

TABLES.DBF     This file describes the numeric data tables.

CNAMESss.DBF   This file lists county names and FIPS codes for State <ss>.

>>Index Files<<
CNAMESss.NDX   This is a dBASE III index file for CNAMESss.DBF.
               Key field is ANPSADPI.

STF3AMss.NDX   This is a dBASE III index file for STF300ss.DBF.
               Key fields are SUMLEV + CNTY + COUSUBFP + PLACEFP + 
               TRACTBNA + BLCKGR.

STF3APss.NDX   This is a dBASE III index file for STF300ss.DBF.
               Key fields are SUMLEV + PLACEFP.

STF3ATss.NDX   This is a dBASE III index file for STF300ss.DBF.
               Key fields are SUMLEV + CNTY + TRACTBNA + BLCKGR.

STF3ALss.NDX   This is a dBASE III index file for STF300ss.DBF.
               Key fields are SUMLEV + left(ANPSADPI,1).  
               This index is UNIQUE.

TABLES.NDX     This is a dBASE III index file for TABLES.DBF.
               Key fields are TABLE + FIELD.


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