tag:blogger.com,1999:blog-4384692836709903146.post684705417911161490..comments2024-03-18T04:38:01.678-07:00Comments on Dispatch from the Digital Health Frontier: Consistent TimeJohn Halamkahttp://www.blogger.com/profile/04550236129132159307noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-4384692836709903146.post-92027953730708661002009-12-10T10:53:25.057-08:002009-12-10T10:53:25.057-08:00The time coordination issue inevitably involves th...The time coordination issue inevitably involves the measurement and retention of time offset(s), whether fractions of a second for time creep or hours for timezones. Time translation must occur somewhere in the 'federated' system. For the HIE, a natural choice would be UTC/UT1/Zulu. Each participating system would then perform time translation for it's local time zone only, and would not need to maintain multiple offsets for every constituent in the HIE federation. Legacy or otherwise, this ability is a requirement whether for HIEs across time zones (hours) or across town (seconds).Wes Knoxnoreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-16435004781293215252009-12-08T12:07:46.956-08:002009-12-08T12:07:46.956-08:00Minor nitpicking: The terms "Zulu time" ...Minor nitpicking: The terms "Zulu time" and GMT has been superceded by Coordinated Universal Time (UTC): http://en.wikipedia.org/wiki/Coordinated_Universal_Time for this use. All system clocks should run on UTC, while time zone calculations will give a correct local time.oddbjornhttps://www.blogger.com/profile/17086322286373024745noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-85724080985129929962009-12-08T09:07:45.111-08:002009-12-08T09:07:45.111-08:00"Ditto" regarding the earlier time zone ..."Ditto" regarding the earlier time zone comment. <br /><br />I'm personally a fan of using Greenwich Mean Time (GMT) when storing date/time in a database. It tends to isolate the chaos associated with moving around the date of Daylight Saving Time observance. I actually desire that time zones/DST be abolished to remove the possibility of off by 1 hour errors and help facilitate meet ups.Chuck Jaegerhttps://www.blogger.com/profile/15706184253946480396noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-89307611474408260512009-12-08T06:49:33.716-08:002009-12-08T06:49:33.716-08:00The US Military, aviation and several other indust...The US Military, aviation and several other industries have a simple solution for time synchronization, and it's called Zulu time or GMT (Greenwich Mean Time)(http://wwp.greenwichmeantime.com/info/timezone.htm). Everywhere on the planet Zulu time is the same. The local time zone is calculated in relation to the number of hours it is ahead or behind Zulu time. <br />- For example, Eastern Standard Time is Zulu time - 5 hours. <br />- Central Standard Time is -6 hours from Zulu time. <br />- Japan is Zulu time +9 hours.<br />- Daylight savings time changes do not change Zulu time.<br />Using Zulu time (or GMT) to record event timing synchronizes events everywhere on the planet. Every time you travel by airplane (anywhere in the world) the flight uses Zulu time to record and coordinate all events related to the flight.Mchael Neecehttp://www.flowlogic.comnoreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-75140226581140916112009-12-07T12:33:47.793-08:002009-12-07T12:33:47.793-08:00This is an issue for organizations that span time ...This is an issue for organizations that span time zones. I have also seen issues with "legacy" hardware that does not sync to any time server...the process for setting the time on a mainframe may be "I look at my watch during the quarterly IPL"<br />We cannot forget how much healthcare depends on legacy systems.geekgoaliehttps://www.blogger.com/profile/15912738758081145206noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-24044772213164244242009-12-07T10:41:50.414-08:002009-12-07T10:41:50.414-08:00It might not be unreasonable for the HIE to query ...It might not be unreasonable for the HIE to query each connected organization daily to get a snapshot of their current timestamp and record it compared to the HIE's timestamp. This may help at a future date when trying to reassemble audit trails that span multiple organizations.Larry Garberhttps://www.blogger.com/profile/11133538970777806147noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-74269711539476473642009-12-07T10:32:59.895-08:002009-12-07T10:32:59.895-08:00I agree that timing is critical. I do not think th...I agree that timing is critical. I do not think that requiring HIEs and participants to install timing systems or sync to other highly accurate time sources before exchanging data is unreasonable. A rubidium clock with PC interface, GPS based clock, or CDMA based clock are all readily available and very inexpensive in this day and age. This type of timing structure is commonplace in other industries to insure the proper operation of systems and accuracy of data. For healthcare environments we’ve found that having a single time source is valuable for things other than audit logs as well. Even simple time and attendance systems have benefited greatly and reduced complaints by staff when the PC clock does not match their timecard clock which doesn’t match the time display on phones for example.Anonymoushttps://www.blogger.com/profile/10103993694677009345noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-58614460096683594072009-12-07T10:05:08.847-08:002009-12-07T10:05:08.847-08:00I agree that audit is not the only, or perhaps eve...I agree that audit is not the only, or perhaps even the most important, business justification for time consistency. Consistent time is equally important for system stability and service availability. <br /><br />Also, in addition to the NTP protocol, we may need standards around time source and stratum level, since each stratum level introduces further delay.Dixie Bakerhttps://www.blogger.com/profile/03486516651040409665noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-12242686043667426122009-12-07T07:57:41.318-08:002009-12-07T07:57:41.318-08:00Actually, Concistent Time, as it was created by IH...Actually, Concistent Time, as it was created by IHE, was not just intended for audit logging. There are a number of reasons why time synchronization is important in healthcare, not just audit trails.<br /><br />It happens to be very easy to implement on any platform. See http://wiki.ihe.net/index.php?title=Consistent_TimeKeith W. Boonehttps://www.blogger.com/profile/16883038460949909300noreply@blogger.comtag:blogger.com,1999:blog-4384692836709903146.post-90691132468865311312009-12-07T07:30:48.720-08:002009-12-07T07:30:48.720-08:00I think requirement §1 should be enough; if the re...I think requirement §1 should be enough; if the relevant systems are running with NTP synchronization (either against internal time sources (GPS, radio), external (pool.ntp.org) or their communication partners), the drifts should be tiny fractions of a second. If you need higher granularity than this, I think real transactional systems are the only way to go. <br /><br />A better §2 would be to ask that the providers to monitor the time drifts of their communication partners. This would likely detect large drifts, and there would be degree of dual control.oddbjornhttps://www.blogger.com/profile/17086322286373024745noreply@blogger.com