Microsoft Year 2000 Readiness Disclosure & Resource Center

Product Summary

Product: Excel 97 Version: 8.0 Category: Compliant* Operating System: 32-Bit Win Language: Chinese - Simplified Release Date: 01 Nov 1996 Operational Range: 01 Jan 1900 - 31 Dec 9999 Prerequisites: Office 97 Service Release 2 Product Dependencies: Windows 95, Windows 98 or Windows NT 3.51 with Service Pack 5 or greater, or Windows NT 4 (no specific Service Pack is required, though Service Pack 2 is recommended) Clock Dependencies: System clock Last Updated: 17 Sep 1999

Product Details

Product Maintenance: While Microsoft continues to recommend that customers install the most current Service Pack/Release for non-Year 2000 reasons, we understand that, for many reasons, this may not be possible. In order to aid our customers' Year 2000 efforts, Microsoft intends to maintain Office 97 Service Release 2 as compliant through January 1, 2001. Newer Service Packs are also to be maintained as compliant, and may include additional non-Year 2000 updates. This is intended to minimize the Year 2000 as a reason to upgrade. Prerequisites: Office 97 Service Release 2 (SR-2) is required for Year 2000 compliance. SR-2 can be downloaded from http://officeupdate.microsoft.com/Articles/sr2fact.htm. The changes in Office 97 that were made in SR 2, including Y2K updates, are listed in http://support.microsoft.com/support/kb/articles/q151/0/20.asp. All Y2K issues reported as fixed in SR2 exist in SR1 and in the base Office 97 product. Notes for East Asian versions of Excel East Asian versions of Excel 97 Service Release-2 (SR-2) include a new method for parsing Gregorian dates. The new behavior is optimized to be the easiest way to deal with dates in the 2000s. East Asian versions of Excel 97 SR-2 also contain the old method for parsing Gregorian dates. The default setting for Chinese Simplified Excel 97 SR-2 is the new method for parsing Gregorian dates. To switch between the two date-parsing behaviors, look on the SR-2 CD under \Valupack\XLParse for the following two files: "Newparse.reg" and "Oldparse.reg." If you have upgraded to Office 97 SR-2 by using the downloadable update, these two files are located on the hard drive in the \Office folder, which is usually found under \Program Files\Microsoft Office. Double clicking a file sets a registry key so that the next time Excel starts up, it is in the desired date-parsing mode. In this document, any reference tagged with (Old Date-Parsing Mode) applies both to Excel 97 SR-2 in the old parsing mode and to Excel 97 SR-1 and earlier versions of Excel 97. References not tagged with (Old Date-Parsing Mode) apply to the new date-parsing mode found in SR-2. How the product handles dates: Storage. Excel stores dates as numeric values, with day 1 being 1900/01/01. Excel 97 recognizes 1900/01/01 through 9999/12/31 as valid dates. Visual Basic (VB) and Visual Basic for Applications (VBA) use the same serial date system, with the exception of 1900/01/01 through 1900/02/28, 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. Previous versions of Excel recognize 1900/01/01 through 2078/12/31 as valid dates. 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 ("yy" refers to a 2-digit year), then even when the user types a 4-digit-year (yyyy) date, it will by default display in a 2-digit-year (yy) format. The date format is customizable. For customers requiring the highest level of assurance concerning the reliability of their date data, it is recommended that users change the system short date to a "yyyy" format. Parsing on date entry. If a user enters a date in a "yy/m/d" or "yy-m-d" 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, 25/1/1 parses to January 1, 2025. To avoid confusion and to show the century clearly, it is recommended that users display dates in a "yyyy" format. (Old Date-Parsing Mode) If the system date separator matches the date separator used to enter a date with a 2-digit year, it will parse to a 1900 date. For example, if the system date separator is a dash and the user enters a date in a "yy-m-d" format, then it will parse to a 1900 date. To avoid ambiguity, dates should be entered in a "yyyy-m-d" format. (Old Date-Parsing Mode) If the system date separator does not match the date separator used to enter a date with a 2-digit year, it will parse such that 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, if the system date separator is a dash and the user enters a date in a "yy/m/d" format, such as 25/1/1, it will parse to January 1, 2025. To avoid ambiguity, dates should be entered in a "yyyy/m/d" format. (Old Date-Parsing Mode) On a default Chinese Simplified system, if a user enters a date from the 2000s in an "mm/dd/yy" format, some cases will be interpreted as a "yy/mm/dd" format. To avoid ambiguity, dates should be entered in a "yyyy/mm/dd" format so that the date can be clearly understood. 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. The East Asian Date Migration Wizard, discussed under "Common date usage errors," will be available soon to 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. 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 Knowledge Base 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 date entry in a macro only records the year according to the system short date format, which results in parsing a 2-digit year in playback. For more information, see Knowledge Base article Q180159. 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 01 is small enough to be interpreted as a day of the month. For more information, see Knowledge Base 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 doesnÆt 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. Microsoft is creating the following add-in tool to help users identify Year 2000 issues in solutions created in Excel 97: The East Asian Date Migration Wizard is designed to help users find instances where date-related arguments reference text dates. The wizard will be available at the Microsoft web site shortly. This document will be updated with the hyperlink to the wizard when it is available. 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 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, "yyyy/mm/dd"). 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 Knowledge Base 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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