Non-Volatile File System: Difference between revisions

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'''Non-Volatile File System''' ('''NVFS''') is a [[Flash memory#Flash file systems|flash memory file system]] introduced in the release of [[Palm, Inc.|Palm's]] [[Personal Digital Assistant]] handheld models [[Tungsten T5]], [[Tungsten E2]], [[TX (handheld)|Palm TX]], [[Z22 (handheld)|Z22]], [[Treo 650]]/[[Treo 700p|700]]/[[Treo 680|680]]/[[Treo 755p|755p]], and [[Palm Centro]].

NVFS was developed to retain all data even if the battery runs out of power, a significant improvement from previous designs that lost all stored data upon power loss. The system uses NAND flash memory technology, which consumes less power and makes charging less frequent. However, due to NVFS's architecture, using clusters of 512-byte blocks, some power users have complained that files take up around 33% more space than in volatile file systems. palmOne addressed this by offering a free 128MB SD Card and committing to reduce NVFS overhead through updates. A notable update improved memory management efficiency by reducing the block size from 512 bytes to 16-32 bytes.

==Background==

===Overview of NVFS===

The NVFS, as claimed by palmOne, is a file system designed to keep all information safe should the battery run out of power. Previous non-flash memory designs would lose all stored data in the event of a power loss. ''NVFS'' is a derivative of [[Flashflash Memorymemory]], which continually stores all data even when no power is applied. palmOne invented NVFS in response to complaints that a handheld's data was destroyed when the battery power ran out. In the past, it was necessary to keep the handheld continuously charged to avoid losing data, since all information was stored in volatile memory.

A similar feature has been adopted by [[Personal digital assistant|PDAs]] running the [[Windows Mobile]] 5.0 [[operating system]], and is named "Persistent Storage".

===Architecture and specifications===

NVFS uses [[NAND flash memory]] technology to retain the handheld's data in the event of a battery swap or if the battery runs out of power. [[Palm, Inc.|palmOne]] claims that Flashflash memory is a plus for the majority of their consumers since many of them do not want to charge the handheld too often, and it consumes less overall power. NVFS uses a brand-new data architecture which might render incompatible some applications which ran very well with non-NVFS handhelds.

===Controversy and unfavorable remarks from power users===

Because the NVFS File System was designed to use clusters of 512 [[byte]] blocks, power users have complained that files take approximately 33% more space than in volatile file systems. In fact a volatile file system uses a block size of only 14 bytes, compared to the NVFS File System minimum block size of 512 bytes. palmOne responded to this complaint by offering a free 128 [[megabyte]] [[Secure Digital Card|SD Cardcard]] on request to selected customers.<ref>{{cite web |url=http://www.pcworld.com/news/article/0,aid,118736,00.asp |url-status=dead |archive-url=https://web.archive.org/web/20050207091154/http://pcworld.com/news/article/0,aid,118736,00.asp |archive-date=2005-02-07 |title=PCWorld.com - New File System Constrains Treo 650 Storage Capacity}}</ref> At the NVFS Early Release, Palm (at the time palmOne) would{{clarify|date=May 2016|reason=They would do this if what? The use of "would" here is confusing.}} commit itself to work on a ROM Flash Update to reduce the overhead of the NVFS Architecture. Currently Palm-branded products using NVFS should be shipped with the NVFS Fix already installed. (The Tungsten E2 uses 4kb blocks.) (It is recommended those having earlier versions of the Palm Treo 650 and Tungsten T5 install the NVFS Fix at the earliest possible convenience). Such controversy gave the [[Tungsten T5]] and the [[Treo 650]] unfavorable remarks from power users.{{citation needed|date=April 2012}}

===Later developments===