1. Apparatus, comprising: a memory; and a processor, which is configured to send to a storage device a request from an application to retrieve data from the storage device, so as to cause the data to be transferred from the storage device to the memory, to send to the application an acknowledgement that the requested data is available in the memory before the data has been fully transferred from the storage device to the memory, and, when the fetched data is ready in the memory, to provide the data to the application.