Project Roseline


Accurate and reliable knowledge of time is fundamental to cyber-physical systems for sensing, control, performance, and energy efficient integration of computing and communications. This simple statement underlies the RoseLine project.  Emerging CPS [Cyber Physical Systems - vy]  applications depend on precise knowledge of time to infer location and control communication.…

Cassandra


[caption id="attachment_1796" align="alignright" width="346"] Cassandra's unfortunate end.[/caption] Cassandra is quite interesting - and time sync seems increasingly critical to correct operation. Here are some resources: A paper on the storage model from developers at Facebook. A reasonably clear introduction from IBM Developer Works. A big difficulty for people who are,…

From Jersey to Wall Street – or the equivalent


A common configuration for FSMLabs TimeKeeper customers is to cross-couple time sources in New Jersey and New York City or London and Slough or Chicago and Aurora or Singapore and Sidney- any two trading locations that are connected with high quality network. Sometimes the network connection does not even have to…

Cassandra Cluster Synchronization


Cassandra is a highly-distributable NoSQL database with tunable consistency. What makes it highly distributable makes it also, in part, vulnerable: the whole deployment must run on synchronized clocks. It’s quite surprising that, given how crucial this is, it is not covered sufficiently in literature. And, if it is, it simply refers…

Time Maps in Action


This shows a time map for a client (center) that is getting NTP time from a variety of standard internet NTP servers and via a customer site (to the left). A TimeKeeper Pocket GrandMaster (bottom left) is serving multiple Stratum servers within the Customer network and we are connecting our…

Efficient Optimistic Concurrency Control Using Loosely Synchronized Clocks


Efficient Optimistic Concurrency Control Using Loosely Synchronized Clocks This paper describes an efficient optimistic concurrency control scheme for use in distributed database systems in which objects are cached and manipulated at client machines while persistent storage and transactional support are provided by servers. The scheme provides both serializability and external consistency…