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[Graphic: On Your Desk]
Your PC and the Year 2000


What do you need to do for your office or home desktop computer to be ready for the year 2000? Here is a quick look at some of the issues, as well as some tips to keep in mind.

How Macs and DOS/Windows Computers Handle Dates

Dates in personal computers are handled at three different levels:

Problems relating to the year 2000 may occur at any or all of these levels.

The BIOS is a small program that handles low-level operations in the computer. One of BIOS' tasks is to read a clock on the computer motherboard and pass the time and date to the operating system. Many older versions of BIOS programs on DOS/Windows(R) computers have bugs that will result in incorrect dates after the year 1999.

The operating systems on both the Macintosh(R) and DOS/ Windows computers include a number of time and date utilities that may be called by programs running on the computer. For example, your word processing program uses one of these utilities to retrieve the operating system's date and time when it sets the revision date in a document you are working on. On both Macintosh and DOS/Windows computers, these utilities should work well after 1999, if the operating system has the correct date and time.

Finally, within programs such as spreadsheets, word processors, statistical packages, and databases are additional date and time functions that perform calculations on user-supplied data. These include such things as determining what day of the week a date falls on, or calculating the number of days between two dates. Many such functions only work over a limited range of years. Check any macros, procedures, and analysis programs you have created using such functions to be sure they will work properly with dates beyond 1999.

The Basic Input/Output System (BIOS)

The BIOS program in general serves as an intermediary between the operating system and computer hardware (motherboard, drives, etc.). Because hardware designs vary among different manufacturers, there are many different versions of BIOS programs, each intended for a specific manufacturer and model of computer.

Because of the way they handle dates, Macintosh computers simply do not have a problem in this area. However, many older BIOS programs on DOS and DOS/Windows computers will not handle years beyond 1999 well. In some cases, if the clock date is set beyond 1999, the BIOS resets the date back to 1980 each time the computer is turned off. Some early DOS computers do not accept system dates past 1999 at all.

While your computer will still work with an incorrect system date, doing so may complicate or prevent date-and time-related functions such as:

C&C's Computer Maintenance Group (CMG) can supply and install BIOS upgrades for Intel computers if the upgrades are available. When an upgrade cannot be found, Eric Beam, CMG's manager, warns that it may be necessary to replace the computer's motherboard or get a new computer.

Extensive information about year 2000 compliance of BIOS for various types of computers can be found at the Y2K Web site at www.mitre.org/research/cots/COMPLIANT_BIOS.html

Operating Systems

Macintosh and DOS/Windows operating systems will be able to handle dates correctly for some years after the turn of the century. The file creation/time stamps for Microsoft(R) DOS and Windows operating systems are good until the year 2108; for the Apple Macintosh operating system, until 2019.

Other operating systems (Linux, Novell(R) Netware, etc.) should do fine also.

Programs

Older programs, custom-written programs, and user-written macros and procedures are the ones most likely to fail. If you are using such programs, carefully test them and review how they work.

Most current, commercially-marketed programs (including spreadsheets, databases, and word processors) should be unaffected by the arrival of the year 2000. However, it is important for you to be clear how your programs are handling date-related information.

Some problems will be encountered in processing user-provided data in spreadsheets and databases if dates have been entered or are computed in two-digit shorthand. For example, you might enter 01 into a spreadsheet cell thinking it will be interpreted as 2001, only to have it automatically converted to 1901.

Microsoft Excel assumes that two-digit shorthand dates of 00-19 are really 2000-2019, but 20 resolves to 1920. Excel 97 will make 00-29 be 2000-2029. You can avoid confusion by using four-digit dates.

Microsoft Access currently resolves all two-digit dates to 19xx, but Access 97 resolves 00-29 to 2000-2029, just like Excel 97.

Date functions and data in most programs only work with a limited range of years. In Excel, for example, the range is from 1900 to 2078. Enter a date outside that range and it will be interpreted as a text string. Date-related functions, such as "day of the week" and "days between dates," will not work on such text strings.

Testing Your System

In general (see the warning that follows), you can test your computer system by manually setting your clock a few minutes before midnight, December 31, 1999. Then wait to see what happens.

The correct system date is one thing to check. You would probably want to try out all major applications that you use to make sure there are no surprises.

WARNING: This should only be done on a fully backed-up or non-production machine because the problems that can arise are sometimes not recoverable just by setting the date back. Some applications could corrupt data files and, in the unlikely worst case, there may be no going back other than completely rebuilding the machine's software.

Additional Tips

Personal computers are often used to send and receive data from other computers, which creates other vulnerabilities:

One more thing: 2000 is a leap year! This can throw off day-of-week calculations for some custom programs. Check to see if your computer will get the leap year correct in February 2000.

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University of Washington Computing & Communications
Windows on Computing, No. 20, Autumn 1997
newsltr@cac.washington.edu