Crouch-Echlin and Time Dilation and y2k : LUSENET : TimeBomb 2000 (Y2000) : One Thread

I posted this on's forum and wanted to share it with the group...

I picked this up from Cory Hamasaki's DC WRP [...] --------------------------------------------------------------------- "TD, Time Dilation, the Crouch-Echlin Effect or CE/TD is an elusive but serious aspect of the larger Year 2000 issue that was discovered by Jace Crouch and Mike Echlin and first reported on the newsgroup

Specifically, TD refers to the time and date instabilities that will occur in the year 2000 and beyond on some personal computers and some embedded systems. These time and date instabilities occur when BIOS time and date routines improperly access a non-buffered RTC during startup, resulting in a personal computer or an embedded system that has difficulty calculating or retaining the correct time and/or date in the year 2000 and beyond.

On these systems the time and/or date will intermittently and abruptly "leap" forward (or occasionally backward) when the system is powered up, not only causing the system to display and store an incorrect time and date, but also leading in certain instances to the failure of com ports and hard drives, cmos scrambling, the OS ceasing to function properly because it is suddenly operating at a date beyond its original design parameters, and occasionally resulting in a system that will not boot up, or even make it out of POST.

These time and date instabilities can occur after the year 1999 because the BIOS then takes longer to access and process data obtained from the RTC, and on systems with a non-buffered RTC the BIOS may do this while the data is incorrect. In the era 20xx, a non-buffered RTC accessed shortly before the update flag is set may return bad data because the time and date calculations take longer than 244 microseconds in the era 20xx and the calculations may extend into the period when the RTC is in update status.

If this occurs when the RTC is accessed during POST, Time and Date instabilities can occur not because this incorrect data used to calculate time and date for the software clock, but also because the incorrect time and date may get written back to the RTC/CMOS, thereby sustaining the time and date errors until the RTC/CMOS is reset by the user or by remediative software.

Occasionally (but devastatingly), the events that result in TD also result in CMOS corruption and/or hard drive boot sector corruption. For a detailed description of how this works, see . [...] -Jace Crouch --------------------------------------------------------------------- My questions;  are utilities taking into account this effect when assessing their systems?  can TD or CE/TD create problems for utilities? Thanks! ---------------------------------------------------------- Asked by Michael Taylor ( on October 29, 1998.


_Any_ IBM PC/AT based embedded systems will almost certainly cause problems for _any_ application in which it is used. I have yet to hear of any system involving more than 3 PCs that did not have to be remediated. In other words if you have any moderately sophisticated embedded system controlling or monitoring _any_ process that involves more than 3 IBM PC/AT compatible boxes the chances are greater than 90% that the system will fail. Period.

Don't pay any heed to these people who say "no problem". I have found that they fall into one of three broad catagories; they are either just plain ignorant and like the sound of their own voice and spouting off on the 'net, or they are not completely ignorant but in denial, or , and the most dangerous class, they do understand the problem but they are over specialised and do not recognise nor understand the scope of the problem.

For a list of realtime clock chips that HAVE the Y2K bug and will NOT be fixed check here: and here:

These chips are used in hundreds of millions of IBM PC/AT compatible embedded systems (and hundreds of millions of IBM PC/AT compatible desktop systems too). These chips are also used in hundreds of millions of other embedded systems of which I know absolutely nothing. I am an IBM PC/AT embedded systems expert (But not overly specialised :-)

Check here to see what an IBM PC/AT compatible embedded CPU board looks like: That board measures 3.5" x 3.25" you can put them everywhere, and people do. Also notice what they say about Y2K (hint: nothing).

Check here for an excellent page describing Y2K problems and embedded PCs: (it also gives a pretty good feeling for the complexity of the issue)

Check here for a "short" list of industries and applications that use embedded PCs: and here:

As I have mentioned many times before there are dozens of embedded OS manufacturers and dozens embedded hardware platforms for the IBM PC/AT compatible market alone. There are also literaly hundreds, maybe thousands of custom/in-house/proprietary embedded kernels and OS's too.

Something else to think about, once you've got your head wrapped around this part of the story remind yourself that the embedded IBM PC/AT compatible market is a small fraction of the overall embedded systems market and hence a small part of the embedded systems Y2K problem.

See my comments in the thread "Gartner Report (98-10-12)" in this forum for more info. Feel free to email me if you'd like further clarification on any of this.

Finally, don't let anyone tell that there is no problem with embedded PCs. They simply do not know what they are talking about.

Regards, Andrew J. Edgar Manager, Systems Software Centigram Communications Corp. Disclaimer: I speak only for myself and from my personal experience. I do not speak as any kind of representative, nor spokesperson of my employer. Answered by Andrew J. Edgar ( on October 30, 1998. ---------------------------------------------------------------------

This may be why we hear that systems will have problems well into the year 2000 and it will be like a rolling storm of problems after problems after p

-- Michael Taylor (, October 30, 1998


I have seen the PC-XT board around. I have always thought of them as a test bed for one-off gadgets or as a hobbyist gimmick. I can't believe that anyone would use one in a critical application. I can't remember ever seeing one used in such a way.

-- Paul Davis (, October 30, 1998.

Paul, the board mentioned above is the PC/AT, not the XT.

Also, the government still owns and uses some 400,000 286, 386 and 486 systems. I would think that they all are able to suffer from many, many y2k related failures. ===================================================================

-- Michael Taylor (, October 31, 1998.

Some are still around, I have part of the job of finding out whether or not they are able to function for whatever purpose they are being used for after 1/1/00. If not, they are replaced. I have seen pretty much no embedded PC's of any stripe around though - generally the designer prefers to simply connect to the device I/O using a RS- 465 interface and keep the PC outside to make upgrades to the PC hardware and software easier and simpler. RS-435 and 465 are pretty cool - they can run for miles and are very stable even in bad EM environments - and are pin out compatible with RS-232. Why the PC ever got stuck with RS-232 I will never know.

-- Paul Davis (, October 31, 1998.

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