DataFlex and the Year 2000 A Data Access Corporation White Paper This document is a Year 2000 Readiness Disclosure under the United States Year 2000 Information and Readiness Disclosure Act. Revised August 24th, 1999 Executive Summary DataFlex has been Year-2000-capable since its introduction. Developers have always been able to write Year-2000-compliant applications. However, primarily for data-entry reasons, and compactness of displays, many, if not most, legacy applications were written in a way that is not Year-2000-compliant. In most cases, correcting such applications involves changes to both the data and the programs. If you have access to your applications' source code and the compiler, you take advantage of solutions that are typically lacking in other application/development environments: Correcting the dates will not require moving any data: four-digit-year data automatically fits into the disk space already occupied by two-digit-year data. You can attain Year-2000 compliance entirely without additional software or other expenditures. Data Access Corporation does offer simple, inexpensive update revisions with which you can retain two-digit-year data entry in the trans-millennial period. To update these products, it is not necessary to change your revision of DataFlex if you have Revision 2.3 (introduced in 1987) or 3.1. Users of DataFlex prior to 3.1 should update to 3.1. All versions (DOS, Console Mode, and UNIX) of DataFlex revision 3.1c and 3.1d, and all Visual DataFlex revisions (6.0 is the most current) include utilities to aid in conversion of two-digit-year data, and support cross-century data entry using two-digit years. The same capabilities are available for DataFlex 2.3 (DOS version only) in a separate product called DataFlex 2.3b Enhanced Runtime. If you have a previous revision of DataFlex 3.x that does not contain these capabilities, getting them is as simple as updating to the current DataFlex Revision 3.1d from Data Access Corporation. It is important to note that a non-compliant application can still be written today in the latest revision of DataFlex. The Year-2000 enhancements of DataFlex require deliberate programming steps to implement them in applications. Merely deploying these with an otherwise-unchanged noncompliant application will very seldom make the application compliant. In fact, all DataFlex licenses are shipped with their enhanced functionality turned OFF in order to protect against mishandling of existing programs and data that have not themselves been modified as described below. The processes of turning the Year-2000-enhancement functionality on and converting existing data are described in the environment guide provided with each product. Some non-compliant applications can be made compliant without recompilation, by updating the revision of DataFlex in which they are running and turning on the Year-2000 enhancements. It is hard to determine and confirm the compliance of such applications without extensive testing of actual and hypothetical data, and for this reason, this method of attaining Year-2000 compliance is neither recommended nor warranteed in any way. Naturally, the Year-2000 compliance of any program, DataFlex or otherwise, will fail if the operating system or firmware under which the program is running is not Year-2000 compliant. Back to top Programs The source code of all your programs must be searched for any and all calculations with, or manipulations of, dates. Once these are found, each must be reviewed for whether they will properly handle four-digit-year dates. Any calculations relying on two-digit-year date constants (e.g., 12/12/50) are likely to need revision, as are uses of the SYSDATE command, which returns a two-digit-year date. You may also have to change the user interface to show all four digits of the year. Once these are corrected, the source code may be recompiled, but the new programs should not be placed into use until the data on which they operate has been converted to four-digit-year (see below). If you have programs that handle dates for which the source code is no longer available, you may still be able to continue using your present applications without change, but this should not be attempted without the original developer and/or a consultant qualified to check DataFlex applications for Year 2000 compliance. Data Access Corporation or a DataFlex distributor may be able to direct you to a consultant or provide the assistance themselves. Back to top Data No DataFlex application using two-digit-year data on disk can comply with Year-2000 requirements. Converting two-digit-year dates on disk to four-digit-year is as simple as adding 1900 years to the dates, which could be done by even a beginning DataFlex programmer. The process of doing this is described on Page 122 of the DataFlex Encyclopedia of DataFlex 2.3 and Page 210 of the Encyclopedia of Revision 3.1. As already mentioned, no change in disk-space allocation is required by this conversion. All data may remain in its present physical position. The only additional space required for conversion is for a backup copy of the data, which may be deleted as soon as the conversion has been completed and the data's results have been confirmed. Just as Year-2000-capable programs should not be used with two-digit-year data, four-digit-year data should not be used with application programs that were designed for two-digit-year dates. Back to top 2000 Is Handled Correctly As a Leap Year All revisions of DataFlex have correctly provided the date February 29 in the Year 2000. Act Now An industry authority recently made this observation regarding the Year 2000 challenge to the IT industry, noting, "This problem is actually little different from other conversion tasks, except for its universal scope and its immovable deadline." (Emphasis added by Data Access Corporation). Back to top Technical Guide The following section is intended as a programmer's guide to the steps necessary to converting existing DataFlex applications to comply with Year 2000 requirements. Some of the following steps apply to every DataFlex application that uses dates in any fashion, even just for reporting. The steps vary according to which revision of DataFlex the application is currently running in, and whether a Year-2000-enhanced revision of DataFlex is to be adjusted. Back to top The Revisions DataFlex always displays its revision number when it starts up. If your main menu is in DataFlex, this will probably happen sometime around the moment you turn your computer on. If your DataFlex application is started from a non-DataFlex menu, this will happen when your application is chosen from the menu. The shaded areas in the table below are considered Year-2000-enhanced. REVISION SYSDATE4? EPOCH? CONV2000 DataFlex 1.x No No No DataFlex 2.0x No No No DataFlex 2.1x No No No DataFlex 2.2x No No No DataFlex 2.3x No No No DataFlex 3.0x No No No DataFlex 3.05e Passive No No DataFlex 3.1 Passive No No DataFlex 3.1c Active Yes Yes DataFlex 3.1d Active Yes Yes Visual DataFlex 4.0 Active Yes Yes Visual DataFlex 5.x Active Yes Yes Visual DataFlex 6.0 Active Yes Yes DataFlex 2.3 Enhanced Active Yes Yes Back to top Revision Regardless of Windows or character-mode. "x" indicates any digit. All lettered sub-revisions are included except where a specific letter sub-revision is listed beneath. Back to top SYSDATE4 This is a command similar to the sysdate command, except that it returns a four-digit-year date from the environment. Its use is optional, and the original (two-digit-year) sysdate command is supported in parallel. "Passive" refers to the support for the command in source code only, while "Active" refers to support for environment settings that convert the returns from the original sysdate commands without recompiling the programs. Active support includes passive support. Back to top Epoch This supports a setting by means of which two-digit-year data entry can be interpreted as 1900s or 2000s according to whether the two-digit year is above or below the epoch value. Epoch values can be set environmentally and/or in code. This functionality is sometimes called "date windowing." Back to top CONV2000 This utility is designed to find date fields in database files and inspect their data. If any such data is found that represents a two-digit year, that data is replaced with the equivalent four-digit-year date. It is a DataFlex program. It is not required for the performance of this process; it is primarily a convenience. With regard to date values in the database, all revisions are alike. Revisions make a difference only with respect to application programs and the system's facilities for managing and converting date data. Back to top Windows vs. Character-Mode When using the epoch functionality to support two-digit-year data entry, the Windows environment supports interface behavior that is significantly different from that supported in DOS, OS/2, UNIX, and XENIX. In Windows, unless picture masking is employed to do otherwise, dates are always displayed in four-digit-year precision, regardless of whether dates are input with two-digit or four-digit years. In character-mode environments, two-digit-year windows are supported for data entry (including display of database values). Thus, such windows will display dates that could be unclear to a user unaware of the epoch value in force. The best method is to use four-digit-year windows for dates. With epoch in force, these will accept and interpret entry of two-digit years, but display values from the database clearly. If four-digit-year windows are impracticable for any reason, the next-best alternative would be to display the epoch value that is in force on the screen in a position as close as possible to the date window(s). Back to top Inspecting Source Code The source code for every program in your application must be inspected for two things: date calculations and uses of the sysdate command. With regard to date calculations, two-digit-year constants should be replaced with four-digit-year constants. For example, the date 9/9/80 should be replaced with 9/9/1980. It is always better practice to use Integer values for date constants, because the calculation is not affected by whatever date format DataFlex is using. Where this was done, you can accomplish the recommended conversion by adding 693975 to the two-digit-year Integer values you find. With regard to sysdate, the same approach is recommended. If the revision of DataFlex you are using has the sysdate4 command (see table above), replace every use of sysdate with the new command. Where the revision you are using does not have the new command, there are a number of ways of modifying the returned value. In fact, such measures may already be in use in your programs. What is recommended in the absence of a sysdate4 command is either to update to one of the revisions listed above as having it, or placing code around each use of the sysdate command to add 693975 to its output. Here is an example of code as you may find it:sysdate image.3 Here is how such code should be modified:date vd2digitsysdate vd2digitmove (vd2digit + 693975) to image.3 Once all date constants have been modified and sysdate statements corrected as described above, recompile all programs whose source code was changed. Do not use the new programs with the old data; they may be used only on data that has been converted as described above. 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