Assessing the Year 2000 Capability of PC System Components : LUSENET : TimeBomb 2000 (Y2000) : One Thread

Assessing the Year 2000 Capability of PC System Components

This paper is separated into the following sections:

How the BIOS and RTC Interact to Maintain System Date and Time

Century Checking and Maintenance in Newer vs. Older BIOS Versions

Timekeeping Mechanisms in OS Software

How can you determine whether or not your OS or NOS is ready for year 2000?

Assessing Year 2000 Capability of Application Software

Year 2000 Test Utilities

It addresses the impact of the transition from 1999 to 2000 on Intel-based PC systems and on specific system components manufactured by Intel. It also discusses how to assess the year 2000 capability of systems and components.

The behavior of any given system during the year 2000 rollover is dependent on several factors including the system configuration, BIOS, operating system and application software. As a result, PC users need to take the following actions:

Check that the system BIOS will update the century information correctly Check that the computer's software, including operating system and application software, can correctly store, recognize and compute dates beyond 1999, including exchanging dates with related software.

How the BIOS and RTC Interact to Maintain System Date and Time

The system date and time in all Intel-manufactured desktop motherboards and server baseboards is maintained in a battery-backed Real Time Clock (RTC) device that also provides a 100-year calendar function. Two-digit values for year, month, day, hours, minutes and seconds are contained in byte-wide registers on the RTC that can be read or written to by software. This RTC register storage format allows the year to be represented by a value within the range of '00' to '99.'

The component that contains the RTC device also contains battery-backed CMOS memory, which stores system configuration data. The system's BIOS uses one byte of CMOS memory (generally, location 32H) to store the century portion of the year-for example, '19' or '20.' By combining the century data in CMOS with the year data in the RTC, software can obtain a full 4-digit year.

Century Checking and Maintenance in Newer vs. Older BIOS Versions

Most newer BIOS versions contain a century checking and maintenance feature that checks the least two significant digits of the year stored in the RTC during each BIOS request (INT 1Ah) to read the date. If less than '80' (i.e. 1980 is the first year supported by the PC), it updates the century byte to '20.' This feature enables operating system and application software using the BIOS date/time services to reliably utilize the year as a 4-digit value.

The BIOS date/time services in some Intel-manufactured desktop motherboards containing the Intel. 386a and Intel. 486 processors had no provision for century checking or maintenance. This means that the CMOS century byte in these motherboards will not automatically change from '19' to '20' following the transition to January 1, 2000.

Therefore, the century byte would need to be manually updated by setting the date following the year 2000 transition. This manual update only needs to be done once; after that the updated century byte will stay in the battery-backed CMOS memory.

Timekeeping Mechanisms in OS Software

An operating system (OS) or network operating system (NOS), together with the computer's hardware, provides the base on which most software applications run. Among other things, the OS and NOS provide time and date services to software applications.

In general, operating systems include a timekeeping mechanism sometimes referred to as a "virtual clock" that is separate from the BIOS and RTC. Typically, the OS or NOS will only read the current date and time from the RTC once during initialization. After that, the virtual clock will maintain the date and time independent of the system BIOS and RTC. Because of this independent timekeeping function, it is important for you to ensure that your OS or NOS is capable of handling the year 2000 transition.

How can you determine whether or not your OS or NOS is ready for year 2000?

Microsoft* Windows* 95 and Windows* 98 are the most commonly used PC operating systems. You should visit Microsoft's dedicated year 2000 Web site for assessments, solutions and upgrades for their OS products. If you don't find what you need at the Microsoft site (or other vendor sites), contact your PC manufacturer for details about how the year 2000 issue will impact your operating system.

. If your PC uses network software, Intel recommends that you directly contact the software vendor, integrator or reseller who sold the software to you. Examples of NOS software include Citrix WinFrame*, Novell NetWare* and Microsoft* TCP/IP network stack. If you are a business user, Intel suggests that you check with the Information Systems or Information Technology division of your organization and ask what you need to do in order to prepare for year 2000.

If you are unable to determine the year 2000 capability of your OS or NOS, you may still be able to determine whether or not the OS or NOS virtual clock is able to manage the transition. A technician that is experienced with your computing environment should be able to safely conduct tests to determine the year 2000 capability of your system.

Generally, if your OS or NOS accesses the RTC through the BIOS, it is the responsibility of the BIOS to update the century byte and provide the correct century information. If the operating system directly accesses the RTC via I/O accesses and not via the BIOS, it is the operating system's responsibility to determine if a century rollover has occurred and update the century byte if required.

Assessing Year 2000 Capability of Application Software

Even if your PC's BIOS and OS are ready for year 2000, some software applications still may not be capable of making the transition.

Applications that have internal calendars or that use dates for the work they do, such as calculating interest or mortgage payments, are the ones most likely to have problems with the transition to year 2000.

Software applications that use dates typically retrieve the date/time from the OS. However, some applications acquire the date/time directly from the CMOS century byte and RTC registers.

These applications may have a problem after the year 2000 transition, even if the system BIOS is "Year 2000 Capable." This is because the BIOS century checking and maintenance feature typically checks the year and updates the CMOS century byte, if needed, only during an INT 1Ah request to read the date. An application that bypasses the BIOS INT 1Ah service to read the date directly from the RTC may read the incorrect century following the year 2000 transition. If the BIOS has not yet issued a INT 1Ah service, the century byte will not have been updated, and the century read by the RTC may be incorrect.

Especially for date-sensitive and mission-critical applications, users should find out whether the software in question will function correctly after 1999. Many commercial software vendors have created statements about whether their products were designed to recognize and handle dates beyond 1999. Users should contact their software vendors or check their Web sites to determine the year 2000 status of specific products.

For independently developed applications, you should do your own assessment of the way in which the applications handle dates. Each application needs to be assessed separately. If date stamping and date calculations are important to your business or application, we recommend doing a thorough assessment of the software.

This assessment should include checking the system configuration and how dates are communicated between applications. The following questions should be addressed in the assessment:

1.Does the application use the operating system to obtain date information or does it access the RTC directly?

If it uses the OS for date information, you have to determine if the operating system is year 2000 capable.

If it obtains the data via the BIOS INT 1Ah service, you should determine if the BIOS is year 2000 capable.

If it access the RTC directly through I/O accesses, you need to make the determination whether or not the application will correctly interpret and handle date functions, during and after the transition to the year 2000, that are normally handled by the BIOS.

2.Does the application recognize 4-digit years or only 2-digit years

If it recognizes only 2-digit years, you should determine whether or not calculations dependent on years are correct for dates that span the transition between 1999 and 2000.

In addition to checking the individual system components, you should make sure that components will work together properly to interpret and handle date functions.

Year 2000 Test Utilities

There are many year 2000 test utilities available on the Web and elsewhere. These tests enable a computer user to determine whether a PC's hardware and BIOS is capable of handling the transition to January 1, 2000.

See Test Utilities Information for specific details.

Some of the test utilities available do not clearly indicate which computer component (BIOS or RTC controller) is being tested. You should carefully review the details of the test utility you select to understand exactly what components of your systems are being tested.

The information here is designated a "Year 2000 Readiness Disclosure" pursuant to the Year 2000 Information and Readiness Disclosure Act, Public Law 105-271.

This information is provided solely for general informational purposes, and not as specific advice or recommendations on how you should prepare your particular business, home, or system for the year 2000 transition. Intel makes no representation or warranty regarding the accuracy, efficacy, or sufficiency of the procedures and information, or the information or results generated by the tests, procedures, or other information provided here. You are solely responsible for the preparation of your business, home, or system for the year 2000.

-- Cherri (, September 18, 1999


If you go to, you can get a FREE on-line checkout done that will tell you the Y2K status of your PC's components (e.g., BIOS, RTC). Of course, when you consider that the vast majority of Y2K problems are actually lurking in your APPLICATIONS, and in the DATA that your applications use -- none of which applies to this stuff at the component level of your PC -- you can see that this is really a waste of time. Especially if you run over a network, which has its own set of problems. Bottom line: Its hopeless!

Gawd, Cherri, how can a polly post such DEPRESSING news?

-- King of Spain (, September 18, 1999.

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