An Introduction to Jorvik, the New Tasking Profile… | The AdaCore Blog

In 2016, AdaCore developed and deployed a new tasking profile based directly on the standard Ravenscar profile, but with some restrictions relaxed or replaced. We presented the new profile in 2017 at Ada Europe [1], providing the justification, additional capabilities, execution-time costs, and resulting schedulability analysis supported. That same year, AdaCore extended SPARK to include the new profile, thus supporting both tasking subsets.

The new profile is included in the Ada 202x draft with some refinements and an official name: Jorvik (pronounced “Yourvick”). Jorvik was the Viking name for a Roman fort/settlement that eventually became known as York, in northern England. Known as England's "Second City," some well-known cities around the world are named after it. The cover picture shows the city today, with the 13th-century Gothic cathedral and its Rose window in the background. York is not far from the village of Ravenscar, where that profile was introduced.

Similarly, Jorvik is not far, technically speaking, from Ravenscar. The differences can be summarized by the small handful of restrictions that are removed or replaced from the Ravenscar list. Everything else in Jorvik remains as it is in Ravenscar. Although the changes are few in number, they are nonetheless significant. We will explore the details below.

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