When Compliance Is Not Enough: How The Y2K Bug Affects the RTC Chip - Industry Trend or Event

Computer Technology Review,  Oct, 1999  by Doug Owen

• E-mail
• Print
• Link

Most of the new computers, motherboards, and accessories manufactured today are being touted as "Y2K Compliant." This phrase generates peace of mind not only for the consumer, but also for resellers and system integrators, none of whom want to hear next year that their products were not up to the challenge of the millennium rollover. But the meaning of this phrase is ambiguous. There are multiple levels of compliance, some of which are appropriate for a limited number of applications and vertical markets. What do the words "Y2K Compliant" mean? Are they sufficient to protect the majority of systems and applications from the Y2K bug?

Amazingly enough, the United States has no official standard of "compliance" that applies to computer hardware and the matter is further complicated by the fact that the date is maintained in three separate ways in the typical PC. The operating system has one clock, which provides the time you see on your desktop and the BIOS has its own date and time-handling routines. However, all date and time values ultimately are derived from the Real Time Clock or RTC chip on the motherboard. With its own battery and circuitry (much like your digital watch) the RTC keeps track of the time and date whether the computer is on or off. Because the computer's CMOS memory also needs battery power, it is usually contained on the same chip as the RTC.

CMOS Setup

There are seven bytes (or registers) of this CMOS memory allocated to store the time and date information, and in most PCs, six of these are updated directly by the RTC. That seventh register contains the two century digits. Only a tiny minority of RTC chips updates the century byte. The rest rely on the BIOS date-handler to update the seventh register when the time comes.

There is no doubt that a BIOS that does this properly can be called a Y2K-compliant BIOS. Yet does this constitute a Y2K-compliant computer? According to an alliance comprised of most of the major PC hardware manufacturers, the answer is a resounding yes. At www.pcy2000.org, you can read a version of Y2K compliance that has been carefully crafted to define the issue in exactly these terms.

In the absence of an official compliance standard, this has become the most widely accepted definition of compliance for PC hardware. The truth is, for the great majority of users, the level of compliance provided by an up-to-date BIOS will do just fine. Every time the computer is booted up, the BIOS will do its date routine that includes checking to see if the century has turned, if so, it will change that seventh CMOS register from a 19 to a 20. Likewise, the user can do a manual date change anytime after the New Year and the century will keep its updated value from then on. Even if the computer stays online, there will be no problem as long as the applications running on that system invoke the BIOS date-handler for any date information (assuming a compliant BIOS, of course).

The only set of circumstances requiring the RTC itself to be compliant is where a system that stays online over the turn of the century is also running software that goes directly to the RTC for its date values. After the rollover, that software will receive a date of 1900 until a reboot or some other outside source triggers the BIOS to update the RTC century byte.

This might seem like an obscure technical point, except for two very important reasons: First, lawsuits over Y2K liability are anticipated by many sources to run into the hundreds of billions of dollars. Second, although the scenario combining 24-hour online systems and direct RTC access may be uncommon, it certainly crops up in some very key places, affecting everything from national defense to nuclear power to Fortune 500 manufacturing plants.

Pundit Platitudes

Initially, some pundits claimed that software directly accessing the RTC did not exist. When it was pointed out that Windows NT, Novell, Unix, and about 60 other PC operating systems all access the RTC chip in some way, the tune was changed to "no applications access the RTC." This was further refined to "no COTS (commercial off-the-shelf) applications." Apparently, no one knows the exact extent of the practice of using the RTC for date information, but we did find two examples even within the limited software library of our own company. Both our payroll program and our order-entry database directly access the RTC for date and time. Each of these packages is only available from the manufacturer, so anyone wanting to nit-pick could argue that they are not really COTS.

So, what does this mean for the hardware reseller? Any expertise I have on this issue is technical and not legal, so please consult your legal counsel regarding your own liability. However, if you sell a computer labeled as Y2K-compliant (within the guidelines issued by the hardware manufacturers) but fail to disclose that it could give a date of 1900 under certain circumstances, be prepared for trouble. On the other hand, disclosing this window of non-compliance without offering a cure is bound to have a negative impact on sales.