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zram

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This article is about the Linux zRam feature, previously known as "compcache"[1]. For the novel dynamic random-access memory technology Z-RAM, see Z-RAM.

zram is a module of the Linux kernel, previously called "compcache". zram increases performance by avoiding paging on disk and instead uses a compressed block device in RAM in which paging takes place until it is necessary to use the swap space on the hard disk drive. Since using RAM is faster than using disks, zram allows Linux to make more use of RAM when swapping/paging is required, especially on older computers with less RAM installed.[1][2]

Even though the cost of RAM hardware is relatively low this feature still offers advantages for netbooks and other lower-powered laptops, virtualization and in the case of embedded devices, especially those that use flash memories that have a limited lifespan, dependent on write-use and thus wear out quickly when used as a swap device.[2]

Efficiency

According to the Gentoo Linux wiki, zRAM typically averages a 3:1 ratio - that is 3Gb of virtual RAM into only 1Gb of physical memory.[citation needed]

Use

Google uses zRAM in Chrome OS and Android 4.4.[3]Google, Android KitKat | Android Developers</ref>

Ubuntu is considering enabling zRAM by default on machines with less RAM installed.[4]

References

  1. ^ a b "Increased performance in Linux with zram (virtual swap compressed in ram)". Web Upd8. 2 October 2011. Retrieved 8 November 2011. {{cite news}}: |first= missing |last= (help)
  2. ^ a b Google Code (27 April 2010). "compcache Compressed Caching for Linux". Retrieved 11 November 2011. {{cite web}}: |last= has generic name (help)
  3. ^ Larabel, Michael (28 March 2013). "Google is Enabling zRAM for Chrome OS By Default". Chrome Story. Retrieved 29 March 2013. {{cite web}}: Cite has empty unknown parameter: |1= (help)
  4. ^ Dinsan, Francis (8 December 2012). "Ubuntu Linux Considers Greater Usage of zRAM". Retrieved 30 October 2013. {{cite web}}: Cite has empty unknown parameter: |1= (help)
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