On the Connections between Types and Service Level Agreements and Implications for Digital Commercial Printing and Other Domains

Digital commercial print providers are increasingly seeing more and more low-value, very short-run orders as a result of personalization and customization of content. In addition, consolidation due to margin pressure and low turnaround times necessitates a quicker reaction to scenarios such as acquiring additional capacity in the peak season or off-loading capacity during the off-peak season. Traditional tools for negotiating and acquiring customer orders are increasingly becoming prohibitive in this environment due to their high costs and lack of ability to make rapid changes. Tools that use machine readable service level agreements (SLAs) promise easier management of customer orders, but are currently not widely used in manufacturing domains such as digital commercial printing. If SLAs are to appear in manufacturing and other related domains, they will need to deal with both SLA Monitoring and SLA Negotiations in the same framework. Programming languages have long used the concept of Types to guarantee behavior of programs. In this paper we show that there is a deep connection between Types and SLAs. The connection stems from the fact that both the Types as well as the SLAs are inherent guarantees about the run-time behavior. The mapping between Types and SLAs is shown by formulating problems in both the domains using notations which have similar semantics. In particular, we show: 1) SLA Monitoring has a parallel in Type Checking, 2) SLA Negotiation has a parallel in Type Inference, and 3) SLA Inhabitation has a parallel in Type Inhabitation. We also briefly mention how the rich meta-theorems about types such as preservation, progress and replacement theorems can be used to reason about SLAs, especially for services which deliver manufactured products.