Non-Volatile File System

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

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 Flash Memory, 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 PDAs running the Windows Mobile 5.0 operating system, and is named "Persistent Storage".

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. palmOne claims that Flash 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.

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 SD Card on request to selected customers [1]. At the NVFS Early Release, Palm (at the time palmOne) would 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.

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