HSLAB Prefetch Manager Business

When trouble shooting either Windows or program start-up issues, it might be helpful to disable the prefetcher using HSLAB Prefetch Manager, because it runs as a background service while other applications are running or loading. When a Windows XP system is booted, data is saved about all logical disk read operations. On later boots, this information is used to prefetch these files in parallel with other boot operations. During boot and application launch, a Windows system demands and pages a sizable amount of data in small chunks (4 KB to 64 KB), seeking between files, directories, and metadata. The Logical Prefetcher, which is new for Windows XP, brings much of this data into the system cache with efficient asynchronous disk I/Os that minimize seeks. During boot, the Logical Prefetcher finishes most of the disk I/Os that need to be done for starting the system in parallel to device initialization delays, providing faster boot and logon performance. Logical prefetching is accomplished by tracing frequently accessed pages in supported scenarios and efficiently bringing them into memory when the scenario is launched again. When a supported scenario is started, the transition page faults from mapped files are traced, recording which page of a file is accessed. When the scenario has completed (either the machine has booted or the application started), the trace is picked up by a user-mode maintenance service, the Task Scheduler. The information in the trace is used to update or create a prefetch-instructions file that specifies which pages from which files should be prefetched at the next launch.