Athanasios E. Papathanasiou

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I/O prefetching serves to hide the latency of slow peripheral devices. Traditional OS-level prefetching strategies have tended to be conservative, fetching only those data that are very likely to be needed according to some simple heuristic, and only just in time for them to arrive before the first access. More aggressive policies, which might speculate(More)
During concurrent I/O workloads, sequential access to one I/O stream can be interrupted by accesses to other streams in the system. Frequent switching between multiple sequential I/O streams may severely affect I/O efficiency due to long disk seek and rotational delays of disk-based storage devices. Aggressive prefetching can improve the granularity of(More)
Although transactions have been a valuable abstraction of atomicity, persistency, and recoverability, they have not been widely used in programming environments today, mostly because of their high overheads that have been driven by the low performance of magnetic disks. A m a j o r c hallenge in transaction-based systems is to remove the magnetic disk from(More)
File systems and databases usually make several synchronous disk write accesses in order to make sure that the disk always has a consistent view of their data, and that data can be recovered in the case of a system crash. Since synchronous disk operations are slow, some systems choose to employ asynchronous disk write operations, at the cost of low(More)
BACKGROUND Catecholamine-producing tumours are called pheochromocytomas when they are located in the adrenal gland and sympathetic paragangliomas when they are located elsewhere in the abdomen. Rarely these tumours do not produce catecholamines and even more rarely they arise in the spermatic cord. Over the past decade, systematic mutation analysis of(More)
PURPOSE Pain rating scales are widely used for pain assessment. Nevertheless, a new tool is required for pain assessment needs in retrospective studies. METHODS The postoperative pain episodes, during the first postoperative day, of three patient groups were analyzed. Each pain episode was assessed by a visual analog scale, numerical rating scale, verbal(More)