Most programming languages provide abstractions for non-local control flow and access to the stack by using continuations, coroutines, or generators. However, their unrestricted use breaks the local reasoning capability of a programmer. Gradual typing exacerbates this problem because typed and untyped code co-exist. We present a contract system capable of protecting code from control flow and s...

The Echo liquid handler enables protein crystal formation with sitting drop volumes as small as 50 nL. Nanoliter volumes of protein and crystallography reagents can be transferred into sitting drop wells of crystallography plates. Precise and accurate drop placement eliminates crosscontamination and ensures drop-on-drop placement for blending protein and crystallography solutions. Precise trans...

This paper introduces and shows how to schedule two novel scheduling abstractions that overcome limitations of existing work on preemption threshold scheduling. The abstractions are task clusters, groups of tasks that are mutually non-preemptible by design, and task barriers, which partition the task set into subsets that must be mapped to different threads. Barriers prevent the preemption thre...

In order to apply the results of formal studies of real-time task models, a practitioner must account for the effects of phenomena present in the implementation but not present in the formal model. We study the feasibility and schedulability problems for periodic tasks that must compete for the processor with interrupt handlers –– tasks that are assumed to always have priority over application ...

We propose and evaluate a new data prefetching technique for cache coherent multiprocessors. Prefetches are issued by a prefetch engine which is controlled by the compiler. Second-level cache misses generate cache miss traps, and start the prefetch engine in a trap handler generated by the compiler. The only instruction overhead in our approach is when a trap handler terminates after data arriv...

The MCP2150 encodes an asynchronous serial data stream, converting each data bit to the corresponding infrared (IR) formatted pulse. IR pulses that are received are decoded, and then handled by the protocol handler logic. The protocol handler will then send the appropriate data bytes to the host controller in UART formatted serial data. The encoding/decoding functionality of the MCP2150 is desi...

The effect of COVID-19 on informant use and management, during the peak imposed Government lockdown measures was felt across English Welsh police Dedicated Source Units. Within these restrictions, staff managing informants had to develop then implement new strategies that delivered safe, yet effective, handling capacity capability. Based a survey 205 respondents directly involved in handling, c...

Effect handlers can be composed by applying them sequentially, each handling some operations and leaving other uninterpreted in the syntax tree. However, semantics of subtle---it is well known that different orders composing lead to drastically semantics. Determining correct order composition a non-trivial task. To alleviate this problem, paper presents systematic way deriving sufficient condit...

class Component { abstract void handleEvent(Event e); }void handleEvent(Event e); } Fig. 30. Base class of components in an event-based system sending messages to one another. Instead, each component is able to announce a set of events. Separately, other components can register to receive notification whenever a certain event is announced by providing a handler procedure for the event. When an ...