ReadyBoost

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ReadyBoost is a disk caching technology first included with Microsoft's Windows Vista operating system. It aims to make computers running Windows Vista more responsive by using flash memory on a USB 2.0 drive, SD card, CompactFlash, or other form of flash memory, in order to boost system performance.

ReadyBoost is also used to facilitate ReadyBoot, an updated version of Windows XP's prefetcher which performs analysis of boot-time disk usage patterns and creates a cache which is used in subsequent system boots.^[1]

Overview

Using ReadyBoost-capable flash memory devices for caching allows Windows Vista to service random disk reads with performance that is typically 80-100 times faster than random reads from traditional hard drives. This caching is applied to all disk content, not just the page file or system DLLs. Flash devices are typically slower than the hard drive for sequential I/O, so to maximize performance, ReadyBoost includes logic to recognize large, sequential read requests and then allows these requests to be serviced by the hard drive.^[2]

When a compatible device is plugged in, the Windows AutoPlay dialog offers an additional option to use it to speed up the system; an additional "ReadyBoost" tab is added to the drive's properties dialog where the amount of space to be used can be configured.^[3] Up to 4 gigabytes of flash memory can be assigned. ReadyBoost encrypts and compresses all data that is placed on the flash device; Microsoft has stated that a 2:1 compression ratio is typical, so that a 4GB cache could contain upwards of 8GB of data.^[1]

According to Jim Allchin, for future releases of Windows, ReadyBoost will be able to use spare RAM on other networked Vista PCs.^[4]

For a device to be compatible and useful it must conform to the following requirements:

• The capacity of the removable media must be at least 256 MB
• Devices larger than 4GB will have only 4GB used for ReadyBoost
• The device should have an access time of 1ms or less
• The device must be capable of 2.5 MB/s read speeds for 4 kB random reads spread uniformly across the entire device and 1.75 MB/s write speeds for 512 kB random writes spread uniformly across the device
• The device must have at least 235 MB of free space
• NTFS and FAT32 are supported
• The initial release of ReadyBoost supports one device

See also

• Features new to Windows Vista

References

1. ^ ^{a b} Mark Russinovich (March 2007). Inside the Windows Vista Kernel: Part 2. TechNet Magazine. Microsoft. Retrieved on 2007-03-01.
2. ^ Matt Ayers (June 2, 2006). ReadyBoost Q&A. Tom Archer's blog. MSDN Blogs. Retrieved on 2007-01-31.
3. ^ Tom Archer (April 14, 2006). ReadyBoost - Using Your USB Key to Speed Up Windows Vista. Tom Archer's Blog. Microsoft. Retrieved on 2006-05-21.
4. ^ Jim Allchin (23 May 2006). Retrieved on 2006-11-01.

External links

Microsoft links

• Windows Vista: Features Explained: Windows ReadyBoost
• Windows Vista Help Page on ReadyBoost
• Windows Vista: Features Explained: Performance Features (of which ReadyBoost is one)
• Channel9 interview with Michael Fortin on ReadyBoost and other performance technologies in Windows Vista

Other links

• SkiZoSnaKe's Blog: How enable Ready Boost on all USB Flash Memory
• ActiveWin ReadyBoost USB Stick test round up
• AnandTech: Windows Vista Performance Guide - ReadyBoost, ReadyBoost Performance Analysis, and Hard Drive Performance and ReadyBoost
• ExtremeTech: USB Flash Memory for Windows Vista ReadyBoost (September 20, 2006)
• In depth Tom's Hardware article with analyses of ReadyBoost and Superfetch
• Lists of compatible ReadyBoost hardware
• Using ReadyBoost on hardware not up to Vista spec