Microsoft Year 2000 Readiness Disclosure & Resource Center

Product Summary

Product: Excel 97 Version: 8.0 Category: Compliant* Operating System: 32-Bit Win Language: Thai Release Date: 21 Jul 1997 Operational Range: 01 Jan 1900 - 31 Dec 9999 Prerequisites: MSQuery software update Product Dependencies: Microsoft Thai Windows 95, Thai Windows 98, Thai Windows NT4 (no specific Service Pack is required, though SP4 is recommended) Clock Dependencies: System clock Last Updated: 17 Sep 1999

Product Details

Prerequisite for Year 2000 ComplianceùMSQuery Patch: To resolve known issues with Excel 97 Thai, Microsoft Query must be updated (see Knowledge Base article Q187698 û MS Query uses 1900 date when two digits are used for year in a query). This issue is addressed for the English version of Excel 97 in Service Release 2. Since this Service Release is not presently available for the Thai version, it is recommended that the software update be applied to address the issue in the Thai version of Excel 97. The software update can be downloaded and installed from the following location: http://www.microsoft.com/thailand/download/xl97y2k.exe Special Note for Thai versions of Excel: Thai Excel 97 supports the Buddhist calendar. Serial date 1 corresponds to January 1, 1900 in the Gregorian calendar and January 1, 2443 in the Buddhist calendar. The only difference between Buddhist and Gregorian dates is that Buddhist year number is 543 larger than the Gregorian. Thai Excel 97 will parse the date entered in a cell according to the Short Date Style set in the Regional Settings of the Control Panel using the Gregorian calendar, even if the Calendar Type has been set to Buddhist. A date in a cell can be expressed either as Buddhist or Gregorian by adjusting the cell format in the Format Cells dialog, on the Number tab, in the Custom category. Replacing yy with bb or yyyy with bbbb causes the date to be expressed with a 2- or 4-digit Buddhist year. Suppose the date May 15, 1998 (serial date 35930) is entered in a cell. Formatting the cell as d/m/yy will show 15/5/98, d/m/yyyy will show 15/5/1998, d/m/bb will show 15/5/41, and d/m/bbbb will show 15/5/2541. How the product handles dates: Storage. Excel stores dates as numeric values, with day 1 being 01/01/1900. Excel 97 recognizes 01/01/1900 through 12/31/9999 as valid dates. Visual Basic (VB) and Visual Basic for Applications (VBA) use the same serial date system, with the exception of 01/01/1900 through 02/28/1900, where the values are different by 1. This difference is a result of a backward-compatibility issue with Lotus 1-2-3, which treats 1900 as a leap year. Formatting. When Excel formats a date, it uses one of several default formats. The most common is the system short date. If the system short date is a "yy" format, then even when the user types a 4-digit-year (yyyy) date, it will by default display in a 2-digit-year (yy) format. Users can avoid this issue by changing their system short date to a "yyyy" format. Planning for 4-digit-year display is important in programs such as Excel, where columns may be fixed by the worksheet author with widths that are too narrow for 4-digit years. Parsing on date entry. If a user enters a date in an "M/d/yy" format, a number less than 30 is assumed to be the year 20xx, while a number equal to or greater than 30 is assumed to be the year 19xx. For example, Excel 97 recognizes 01/01/15 as January 1, 2015, and recognizes 01/01/35 as January 1, 1935. String date parsing during calculations. If a formula takes a string date as an argument, the string date is currently parsed using the same code as the date entry described above. This may be problematic for some users because a formula such as =YEAR("1/1/25") returned 1925 in earlier versions of Excel, but in Excel 97 the same formula returns 2025. Because this only happens when "1/1/25" is a string using a 2-digit-year format, a solution is to change the "yy" date strings to "yyyy" date strings. The Date Migration Wizard, an Excel add-in tool, can also help the user identify and correct these situations. Two-digit shortcut handling: See the preceding discussion. Conversion of 2-digit shortcut dates assumes a date window of 1930 through 2029. For more information, see Knowledge Base (KB) article Q164406. Common date usage errors: If a date is pasted from one program to another using only the last 2 digits of the year, Excel might parse the date differently than the originating program. Example: The date January 1, 1915, is in a non-Excel program. The date is copied, but because the system settings are "M/d/yy," all that is copied is the text "1/1/15." When "1/1/15" is pasted into Excel, Excel parses the date to January 1, 2015. Such an error can also occur when one program is using an "M/d/yy" format while another is using a "d/M/yy" format. This also applies to importing dates from text files. For more information, see KB article Q180159. Because it receives numeric parameters, the DATE() function is not designed to take 2-digit-year shortcuts. The DATE() function calculates a number less than 1900 as an offset from 1900. So, if a formula such as =DATE(15,1,1) is entered, the resulting date is January 1, 1915, not 2015. Recording a date entry in a macro records/plays back the year in yy format even if the user enters yyyy and even if the system short date format was yyyy. For example if the system date was MM/dd/yyyy and the user enters in a cell 12/12/2030, Thai Excel 97 will play it back as 12/12/1930. This may cause problems if the 2-digit year is not meant to follow the 1930-2029 date window that is mentioned above. See KB article Q180159 for more information. Using a format such as "Dec 98" will not function properly at the year 2001. Because 98 is too large to be a day of the month, Excel assumes it is a year. However, Excel assumes "Dec 01" is December 1 of the current year. Because Excel always stores the complete date, users can avoid ambiguity by entering a full date, regardless of the display formatting. For more information, see KB article Q180952. Due to the ambiguous nature of text dates, in general they will always have some potential for error. Whenever possible, use serial dates and take great care when transferring text dates. When dates must be transferred between programs, ideally they should be transferred as serial dates. They should never be transferred as an ambiguous text format that does not specify the century and causes confusion between the month and the day of the month. For example, the text "2/1/25" could be interpreted as February 1, 1925; January 2, 1925; February 1, 2025; or January 2, 2025. Changing the default system short date format to include a 4-digit year and getting in the habit of using 4-digit-year formats will make the date visible if a user mistakenly enters a date in the wrong century. Defined names store references only as text strings. Because they do not store dates as serial values, they are vulnerable to century issues when a "yy" format is used. Using defined names in this way is also problematic because users who use a date format with an order other than M-d-y will experience miscalculations. Both of these potential problems can be avoided by defining the name that refers to a cell containing a serial date. Thai Excel 97 will not display in a worksheet cell the date for the 1st of January for the first leap year following a non-leap century year. Enter "1-Jan-2104"à the cell will display "1-Feb-2104". Note that 2100 is a century year, but not a leap year, and 2104 is the first leap year following. Though the date appears wrong in the cell, the serial value stored in memory is correct. See KB article Q175362 for more information. Microsoft has created the following add-in tools to help users identify Year 2000 issues and solutions in Excel 97 and later versions: The Date Migration Wizard is designed to help users find instances where date-related arguments reference text dates that only specify the last 2 digits of a year--which can cause changes in calculation from earlier versions of Excel. The Date Fix Wizard helps users find errors where the wrong century was entered for a date. It also allows the user to change all date formats in a workbook to formats that display all 4 digits of the year. Finally, it allows the user to scan workbooks for the earliest and latest dates in workbooks. The Date Watch Wizard runs in the background while users work in Excel. It suggests alternatives when ambiguous text dates are entered in cells or functions, changes number formats to 4-digit years when 2-digit years are entered, and displays an alert when text files that contain 2-digit years are opened. For more information about these add-in tools, see KB article Q176943. Testing guidelines and recommendations: In general, avoid testing in a production environment or with nonduplicated production files because side effects with other noncompliant products cannot be predicted. Interoperability testing with other Microsoft Office products can be conducted safely. The following areas should be examined to verify whether dates are being properly used. The following table can be used to guide testing of Excel within your organization. Subsystem Component Testing notes File Various file formats Avoid storing "yy" dates in text file formats such as TXT, DIF, CSV, PRN. The default column width with default fonts may truncate characters with date formats that have eight digits and two separators. To correct this, increase the column width or change the font to a fixed-width typeface such as Courier New. Data Import from: text, databases, external data sources Sort Data imported from databases and other external sources is often imported as text. Imported "yy" dates will be parsed with the 1930-2029 cutoff rule. Because this is different from previous versions of Excel, use "yyyy" dates to prevent confusion. Basic Use Functions Date entry Natural language functions Functions referring to text dates will parse according to the 1930-2029 cutoff rule. Date entry will parse according to the 1930-2029 cutoff rule. Visual Data Charts Because chart labels are normally used for display and not for calculation, they may not be much of an issue. Visual Basic/Visual Basic for Applications (VB/VBA) Transfer between VB/VBA and cells Internally, VBA treats dates as serial values, exactly like Excel does. However, VBA uses the "M/d/yy" format, so users should avoid transferring the date text through VBA because it could parse to the wrong century. This may also help avoid issues with international users who have a system short date format with an order other than M-d-y. Additional Testing Instructions Excel has been designed for calculations in the year 2000 and beyond. Microsoft understands that, for various reasons, customers may be required to conduct their own Year 2000 certification testing. The following tests may aid customers in their own certification of Excel. Users who work with dates will benefit from changing the system short date format to one that uses a 4-digit year (for example, "MM/dd/yyyy"). This change allows the user to clearly see the century of a date. Conducting the tests below is only worthwhile if 4-digit years are used. If you decide not to set your system short date format to include a 4-digit year, you can format each cell individually by selecting Custom on the Number tab (Format menu, Cells command) in Excel, and then entering a 4-digit-year format. To change the system short date format, do the following. On the Windows Start menu, point to Settings, click Control Panel, double-click the Regional Settings icon, and then click the Date tab. In the Short date style list, click a format that includes a 4-digit year ("yyyy"). Test 1--Verify that Excel transitions smoothly into the year 2000: Caution! Before conducting this test, make sure you do not have any software containing a license that expires by the year 2000. This is especially common with beta copies of software programs. If a program determines that its license has expired, it is possible the program will no longer boot, even after resetting the system clock. Changing a system clock on a network can affect other computers connected to the network, so it is highly recommended that you isolate the computer from all other systems before changing the system clock to conduct the following test. Set the system clock to 11:59 P.M., December 31, 1999. Start Excel. In cell A1 (cell R1C1 if in R1C1 mode), enter =NOW(). After 1 minute, press the F9 key to recalculate the formula that you entered in A1. Note that the time and date shown are in the year 2000 and that nothing unusual has happened to Excel. Remember to reset your system clock to the correct time and date after conducting this test. Test 2--Verify that Excel recognizes the year 2000 as a leap year: Start Excel. In cell A1 (cell R1C1 if in R1C1 mode), enter "=DATE(2000,2,28)+1". Note that the resulting date is February 29, which indicates that Excel correctly recognizes 2000 as a leap year. Note: The year 1900 is not a leap year; however, in your testing you may notice that Excel treats 1900 as if it is. This algorithm is by design and was adopted to maintain compatibility with dates in Lotus 1-2-3. The calculation for leap years that is used by the Gregorian calendar is as follows: If a year is evenly divisible by 4, it is a leap year unless it is also evenly divisible by 100. If a year is evenly divisible by 100, it is not a leap year unless it is also evenly divisible by 400. For more information, see KB article Q181370. Excel 97 uses a number of Microsoft Office 97 shared files for the implementation of dialogs and toolbars, task automation, online help, installation, graphics, file find and file I/O. For additional information that is appropriate for Excel 97, please refer either to the document for the particular Office version that this application came with, or, in the case of a standalone product, to any version 97 Microsoft Office document.

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