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How Readyboost
increase the performance of the machine?
- Windows 7 supports Windows ReadyBoost. This feature uses external USB flash drives as a hard disk cache to improve disk read perfor¬mance. Supported external storage types include USB thumb drives, SD cards, and CF cards. Since ReadyBoost will not provide a perfor¬mance gain when the primary disk is an SSD, Windows 7 disables ReadyBoost when reading from an SSD drive.
- External storage must meet the following requirements:
- Capacity of at least 256 MB, with at least 64 kilobytes (KB) of free space.The 4-GB limit of Windows Vista has been removed.
- At least a 2.5 MB/sec throughput for 4-KB random reads
- At least a 1.75 MB/sec throughput for 1-MB random writes
- You can configure ReadyBoost by right-clicking the device in Windows Explorer, clicking Properties, and then clicking the ReadyBoost tab. The only configuration option is to configure the space reserved for the cache. You must reserve at least 256 MB. Larger caches can improve performance, but the ReadyBoost cache cannot be greater than 4 GB on a FAT32 file system or greater than 32 GB on an NTFS file system.
- Windows 7 use the Windows SuperFetch algorithm to determine which files should be stored in the cache. SuperFetch monitors files that users access (including system files, application files, and documents) and pre¬loads those files into the ReadyBoost cache. All files in the cache are encrypted using 128-bit AES if the flash storage device is removable, but hardware manufacturers can choose to disable encryption on internal, non-removable ReadyBoost devices. Because the ReadyBoost cache stores a copy of the files, the flash drive can be removed at any point without affecting the computer—Windows will simply read the original files from the disk.
- ReadyBoost provides the most significant performance improvement under the following circumstances:
- The computer has a slow hard disk drive. Computers with a primary hard disk Windows Experience Index (WEI) subscore lower than 4.0 will see the most significant improvements.
- The flash storage provides fast, random, non-sequential reads. Sequential read speed is less important.
- The flash storage is connected by a fast bus. Typically, USB memory card readers are not sufficiently fast. However, connecting flash memory to an internal memory card reader might provide sufficient performance.
· Can ReadyBoot functionality be somehow related to Hybrid Harddrives? What are Hybrid hard drives?
ReadyBoost was designed to "extend RAM" to help low-level machines, while hybrid drives are designed to improve disk performance for top level machines. The way how ReadyBoost works is: read data from HDD into RAM first, and if you out of RAM push data from RAM to flash drive. ReadyBoost can't improve performance if you have plenty of RAM (actually, it will rather slow your system down).
One major difference is that ReadyBoost is limited to USB 2.0 bandwidth (unless your computer has the ultra-rare and extremely bleeding edge USB 3.0), whereas the hard drive is on the much, much faster SATA interface.
ReadyBoost is also designed around relatively slow I/O constraints, which limits the scope of what it can do, too.
One major difference is that ReadyBoost is limited to USB 2.0 bandwidth (unless your computer has the ultra-rare and extremely bleeding edge USB 3.0), whereas the hard drive is on the much, much faster SATA interface.
ReadyBoost is also designed around relatively slow I/O constraints, which limits the scope of what it can do, too.
- A Memory-mapped file is a file that has been mapped (i.e., not copied) into virtual memory such that it looks as though it has been loaded into memory. Rather than actually being copied into virtual memory, a range of virtual memory addresses are simply marked off for use by the file. You (or Windows) can then access the file as though it were memory, freely changing parts of it without having to make file I/O calls. Windows transparently loads parts of the file into physical memory as you access them. You don’t have to concern yourself with which parts are and are not in memory at any given time.
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Where do you think
we can use MemoryMappedFiles in our projects? Did you make any POCs?http://blogs.msdn.com/b/khen1234/archive/2006/01/30/519483.aspx
- How are memory-mapped files used? Most commonly by Windows itself. Every time a binary image (an .EXE or .DLL, for example) is loaded into memory, it is actually loaded there as a memory-mapped file. The DLLs you see loaded into a process’s virtual memory address space are actually mapped there as memory-mapped files by Windows.
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Where do you think
we can use windows Messages can be used in our projects?
- IIS interacts with w3wp using windows messages
subclassing the form?
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