[LEAPSECS] system engineering best practices

Rob Seaman seaman at noao.edu
Sat Aug 10 15:38:04 EDT 2013

On Aug 10, 2013, at 11:13 AM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:

> Dave Finkleman writes:


>> However, things now broken do not depend on the leap second

>> whereas those that have implemented it correctly obviously do.


> No, there are three classes of systems:


> 1. Those which ignore leapseconds

> 2. Those which handle the leapseconds

> 3. Those which depend on leapseconds


> Estimated ratios: 10,000,000 : 1,000 : 1

A completely ad hoc estimate (with perhaps a slight spin? :-) No comparative impact ranking. Not contrasted with the implications should leapseconds continue. No costing. No schedule. No risk analysis. No systems-of-systems issues. Etc and so forth.

Leapseconds exist for a purpose. An inclination to discount that purpose would benefit from well known system engineering best practices to compare the trade-offs. In the mean time projects that want to ignore leapseconds can choose a different time scale.

Another quote from that data center infrastructure management article:

> The goal is to provide a seamless, real-time view of all elements of data center operations, allowing data center managers to quickly assess a range of factors that impact efficiency and capacity.

Leapseconds are just one of many factors. For instance, the far more massive impact on Amazon of the nearly concurrent electrical storm:



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