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27 Cards in this Set
- Front
- Back
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What is a device file?
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a file representing a system device. dont have data blocks so are small. usually found in the /dev directory.
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Character devices
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devices that transfer data to and from system character by character. slow data transfer. ex: keyboard
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Block devices
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devices that transfer chunks or blocks of data using main memory as the buffer. fast data transfer. ex: hard disk.
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Characteristics of a device file
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consists of file type (block or character), major number and minor number
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File system
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organization imposed on physical storage media
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major #
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points to devices driver in the linux kernel
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minor #
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indicates the device itself in particular
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using ls -l
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replaces the size of the dev files with these major and minor numbers
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formatting
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creating a filesystem on a device
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filesystem
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organization imposed on physical storage media. enables operating system to save and retrieve files.
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ext3
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a journaling file system. it's just ext2 but with journaling.
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journaling
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Journaling was designed for ext3 to help recover quickly from a crash
With a journaling filesystem, a log is kept of all write operations In the event of a crash, the operating system uses the log to restore files in the process of being written to their original state |
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tune2fs
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converts ext3 to ext2 and vice versa
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mounting
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Making a device accessible to users via the logical directory tree
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mount point
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a directory to which a device is attached. any existing directory can be a mount point.
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the Root filesystem
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When Linux boots, a filesystem on a partition of the hard drive is mounted to the / directory
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mount command
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used to mount devices to mount point directories or list all currently mounted filesystems in system if no arguments are implemented
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unmount command
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used to unmount devices
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partition
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a logical division of a disk. can have its own filesystem and mount point
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track
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areas on a hard disk that form cocentric circles
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sector
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smallest unit of data storage on a track, tracks are divided into segments called these
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block
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combination of sectors; commonly used by filesystem commands
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cylinder
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series consisting of the same concentric track on all of the platters inside a hard disk drive
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where are partition definitions stored?
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in the first readable sector of the hard disk (MBR)
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filesystem corruption
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errors in filesystem structure preventing retrieval of data. commonly occurs due to improper system shutdowns.
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syncing
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data to be written to disk is first stored in RAM. syncing is the process of writing data stored in RAM to the hard disk.
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bad blocks
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unusable areas of a disk. they cannot hold a magnetic charge. when found, they are placed in a bad block table so the OS does not try to use
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