March 7, 1991 ------------------------------ Using The CD-ROM ------------------------------ The 1990 P.L. 94-171 software was developed and tested on a COMPAQ Deskpro 286 with 640K RAM operating under MS-DOS 3.31. The software was compiled with Clipper (Summer '87). There are no special display requirements. For direct access to the data files, one of the many software packages which recognize the dBASE III Plus (.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. Please note that the retrieval software will only run on IBM-compatibles operating under MS-DOS. Type GO at the DOS prompt and ENTER. Example: L:\>go ------------------------------ Contents Of The CD-ROM ------------------------------ Volume in drive is PL94_171 DOCUMENT Directory for documentation files. These are ASCII text files containing the complete technical documentation for the data. GO BAT Batch file to execute data retrieval software. PL94 EXE Data retrieval software. PL9417ss DBF P.L. 94-171 data file for State . This is a dBASE III Plus file. PL9417ss NDX Index file for PL9417ss.DBF. See specifications. PL9417ss PLA Index file for PL9417ss.DBF. See specifications. PL94DD DBF Table outline file. This is a dBASE III Plus file. PL94STRU DBF Database structure file. This is a dBASE III Plus file. CNAMESss DBF Data file containing county names for State . This is a dBASE III Plus file. VNAMESss DBF Data file containing voting district names for State . This is a dBASE III Plus file. VNAMESss NDX Index file for VNAMESss.DBF. See specifications. ------------------------------ Index File Specifications ------------------------------ PL9417ss.NDX Key: sumlev+cnty+sac3+cousubce+placece+tractbna+blckgr PL9417ss.PLA Key: sumlev+placece VNAMESss.NDX Key: cnty (UNIQUE) These are dBASE III Plus index files. When several records in a data file have the same key value, only the first record is included in a UNIQUE index. ------------------------------ Technical Documentation ------------------------------ The DOCUMENT directory contains sections of the Public Law 94-171 tape technical documentation in a series of ASCII text files. These are as follow. ROSTER_P.ASC Roster Page ACKNOW.ASC Acknowledgements CONTENTS.ASC Contents ABST_PL.ASC Abstract HOWTOUSE.ASC How to Use the File SUB_LOC.ASC Subject Locator LIST_TBL.ASC List of Tables TBL_OUT.ASC Table Outlines SUM_LEV.ASC Summary Level Sequence Chart USERNOTE.ASC User Notes 1 and 2 IDEN_FTN.ASC Identification Section of the Data Dictionary APPEND_A.ASC Appendix A.--Area Classifications APPEND_B.ASC Appendix B.--Subject Characteristics APPEND_C.ASC Appendix C.--Accuracy of the Data APPEND_D.ASC Appendix D.--Procedures APPEND_E.ASC Appendix E.--Facsimiles of Instructions APPEND_F.ASC Data Products and User Assistance APPEND_G.ASC Maps ------------------------------ dBASE To ASCII Conversion ------------------------------ Users without database management software who wish to convert the files to ASCII can follow this example. This is Microsoft QuickBASIC 4.5 code. Tests on a 286 PC took about 1 1/2 minutes per thousand records reading from CD-ROM and writing to hard disk. TYPE Structure Flag AS STRING * 1 Record AS STRING * 516 END TYPE DIM PL94171 AS Structure OPEN "e:\pl9417vt.dbf" FOR BINARY AS #1 OPEN "c:\pl9417vt.txt" FOR OUTPUT AS #2 SEEK #1, 2947 DO GET #1, , PL94171 IF EOF(1) THEN EXIT DO PRINT #2, PL94171.Record LOOP CLOSE #1, #2 END ------------------------------ Other Software ------------------------------ The Census Bureau's Economic Census Staff has requested that software entitled EXTRACT be made available on this CD-ROM. The EXTRACT software is in the \EXTRACT directory, and related files are in the \AUXIL directory. Questions about EXTRACT should be directed to Paul Zeisset at (301) 763-1792.