unexpectedly. The device can access its own file system while connected: (+) Re-indexing after unplugging can be avoided. Also helped by the inclusion of metadata with the transfer. (+) A separate file system for host exposure is unnecessary. This avoids the inflexibility of setting aside a fixed-size partition for this file system. (+) File system support: The host does not need to support the file system of the device. Conversely, the device manufacturer is free to choose a file system (usually a Linux filesystem unsupported by Windows) other than the widely supported FAT family of filesystems. (-) Undeletion: Filesystem recovery and undeletion tools on the computer cannot be used, since MTP is an abstraction layer that offers no block-level access. (-) Missing time stamps: Many MTP-attached devices, particularly older ones, do not report file timestamps via the protocol, causing them to be lost when files are copied/moved to or from a computer. Some file formats still store timestamps internally, such as JPEG photos with embedded Exif meta data, but the date and time information of files without such internal metadata would be lost. (-) Mislocation: Users have reported files occasionally showing up in incorrect locations as a result of poor communication between the MTP host (e.g. smartphone) and client (e.g. computer file manager). Should a directory be moved away from the MTP host without the client detecting all files, undetected files could end up deleted without all files having been transferred successfully. (-) Truncation: If a file has newly been created on the smartphone while it was connected to the computer through MTP, the computer's file manager could potentially misreport the file size as too small due to having loaded the directory listing in a moment where the file was not complete. Moving the file away from the phone could cause it to be truncated (incomplete) on the target path while being deleted from the source, since the file manager might wrongfully assume that the file has been fully transferred while it hasn't. Performance (-) MTP operations are not multiplexable – any ongoing operation must either complete or be aborted before another operation can begin. Unlike USB mass storage, where the host operating system is free to multiplex block transfers, and logical operations are an emergent phenomenon, the operations supported by MTP are more coarse-grained, such as transferring entire files. Neither protocol is parallel or asynchronous by itself (aside from