Chapter 4 Flashcards
8.3 filename
A filename that consists of no more than eight characters plus an optional dot (.) and three-character extension. This file-naming limit exists in DOS and the original File Allocation Table (FAT) filesystem it uses.
ATA
A popular 16-bit interface standard that extends the ISA bus of the IBM PC-AT to attach peripherals; it has evolved through over 5 generations; the original ATA is better known as IDE.
BIOS
A simple, low-level operating system which supplies a uniform API to higher-level operating systems; BIOS is generally implemented in ROM of some sort.
Boot
To cause the operating system to begin to function. Takes its name from “pulling oneself up by the bootstraps”, a whimsical analogy applied to the BIOS loading itself and then running the “boot loader”.
CHS geometry
A method of hard disk addressing in which a triplet of numbers (a cylinder, a head, and a sector) is used to identify a specific sector. CHS geometry addressing contrasts with logical block addressing (LBA).
Compression
Removal of redundant information from a file or data stream, to reduce its size, the storage space it needs, or the time needed for transmission. Lossy compression actually discards information that is considered not essential, and is only appropriate for data like images or sound.
CPU
The main component that makes a computer work; these days usually a “micro-processor” on a single silicon chip. (See processor.)
CYlinder/head/sector (CHS) geometry
A method of hard disk addressing in which a triplet of numbers (a cylinder, a head, and a sector) is used to identify a specific sector. CHS geometry addressing contrasts with logical block addressing (LBA).
D-Bus
The Desktop Bus (D-Bus) provides a further abstraction of hardware information access. Like hald, D-Bus runs as a daemon. D-Bus enables processes to communicate with each other as well as to register to be notified of events, both by other processes and by hardware (such as the availability of a new USB device).
Direct memory addressing (DMA)
A means of transferring data between devices (such as sound cards or SCSI host adapters) and memory without directly involving the CPU.
DMA
A means of transferring data between devices (such as sound cards or SCSI host adapters) and memory without directly involving the CPU.
DMA Addresses
Direct memory addressing (DMA) is an alternative method of communication to I/O ports. Rather than have the CPU mediate the transfer of data between a device and memory, DMA permits the device to transfer data directly, without the CPU’s attention. The result can be lower CPU requirements for I/O activity, which can improve overall system performance.
EEPROM
Electronically erasable programmable read-only memory (EEPROM)
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A type of data storage chip that retains data when power has been turned off but that can be erased and rewritten electronically. Frequently used to store a computer’s or plug-in card’s firmware.
Electronically erasable programmable read-only memory
A type of data storage chip that retains data when power has been turned off but that can be erased and rewritten electronically. Frequently used to store a computer’s or plug-in card’s firmware.
Enhanced Host Controller Interface (EHCI)
A type of controller for USB 2.0 ports.
ext2
The most common filesystem (meaning 1) in Linux from the mid-1990s through approximately 2001.
Ext2fs
The most common native Linux filesystem (meaning 1) from the mid-1990s through approximately 2001.
ext3
A variant of the Second Extended Filesystem (ext2 or ext2fs) that adds a journal to reduce startup times after a power failure or system crash. See also journaling filesystem.
ext3fs
A variant of the Second Extended Filesystem (ext2 or ext2fs) that adds a journal to reduce startup times after a power failure or system crash. See also journaling filesystem.
ext4
The fourth version of the popular Linux filesystem. Ext4fs adds the ability to handle larger files and filesystems, as well as various performance enhancements, to the ext3fs feature set.
ext4fs
The fourth version of the popular Linux filesystem. Ext4fs adds the ability to handle larger files and filesystems, as well as various performance enhancements, to the ext3fs feature set.
Extended Partition
A type of disk partition in the MBR partitioning scheme. Extended partitions are placeholders for one or more logical partitions.
Extents File System (XFS)
One of several journaling filesystems for Linux. XFS was developed by Silicon Graphics (SGI) for its IRIX OS and then ported to Linux.
Filesystem
Filesystem
The low-level data structures recorded on a disk in order to direct the placement of file data. The filesystem determines characteristics like the maximum file size, the file-naming rules, and what extra data (time stamps, ownership, and so on) may be associated with a file.
The overall layout of files and directories on a computer. For instance, a Linux filesystem includes a root directory (/), several directories under this (/usr, /var, /boot, and others), subdirectories of these, and so on.
Floppy Disk
A magnetic storage medium with a flexible disk inside; See Hard disk.
Fourth Extended File System (ext4fs or ext4)
The fourth version of the popular Linux filesystem. Ext4fs adds the ability to handle larger files and filesystems, as well as various performance enhancements, to the ext3fs feature set.
GPT
A partition table type that’s intended to replace the older MBR system. GPT is defined as part of the EFI specification but can also be used on BIOS-based computers.
GUID
Item 28 of 92 Grade This Item Correct Alt C and Incorrect Alt I
Globally unique identifier (GUID)
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A 128-bit number, defined and expressed in a specific manner. When properly constructed, the odds of two programs, or two runs of the same program, generating identical GUIDs are extremely small.
GUID Partition Table (GPT)
A partition table type that’s intended to replace the older MBR system. GPT is defined as part of the EFI specification but can also be used on BIOS-based computers.
HAL Daemon
The Hardware Abstraction Layer (HAL) Daemon, or hald, is a user-space program that runs at all times (that is, as a daemon) that provides other user-space programs with information about available hardware.
Hard disk
A computer device that uses solid disks as magnetic medium to store data. See Floppy disk.
HFS
A filesystem used on Mac OS.
Hierarchical File System (HFS)
A filesystem used on Mac OS.
High-level formatting
A type of disk formatting that writes the data that define a filesystem. Also called making a filesystem. See also low-level formatting.
I/O addresses
I/O addresses (also referred to as I/O ports) are unique locations in memory that are reserved for communications between the CPU and specific physical hardware devices.
Industry Standard Architecture (ISA)
The expansion bus used on the original IBM PC. Most manufacturers began dropping ISA from their motherboards around 2001.
Inode
A filesystem data structure that contains critical information about the file, such as its size and location on the disk.
IRQ
An interrupt request (IRQ), or interrupt, is a signal sent to the CPU instructing it to suspend its current activity and to handle some external event such as keyboard input
ISA
The expansion bus used on the original IBM PC. Most manufacturers began dropping ISA from their motherboards around 2001.
JFS
One of several journaling filesystems for Linux. JFS was developed by IBM for its AIX OS. A subsequent implementation was created for OS/2, and Linux’s JFS is derived from this code.
Joliet
An ISO-9660 extension commonly used on CD-ROMs and related optical media. Joliet supports Microsoft-style long filenames and is frequently present on CD-ROMs.
Journal
An advanced filesystem feature that records data about pending disk operations. See journaling filesystem.
Journaled File System (JFS)
One of several journaling filesystems for Linux. JFS was developed by IBM for its AIX OS. A subsequent implementation was created for OS/2, and Linux’s JFS is derived from this code.
Journaling filesystem
A type of filesystem that maintains a record of its operations. Such filesystems can typically recover quickly after a power failure or system crash. Common Linux journaling filesystems are ext3fs, ReiserFS, JFS, and XFS. See also filesystem.
Kernel module
A driver or other kernel-level program that may be loaded or unloaded as required.
LBA
A method of accessing data on a disk that uses a single sector number to retrieve data from that sector. LBA contrasts with cylinder/head/sector (CHS) addressing. Some sources refer to LBA as linear block addressing.
Linear Block addressing (LBA)
A method of accessing data on a disk that uses a single sector number to retrieve data from that sector. LBA contrasts with cylinder/head/sector (CHS) addressing. Some sources refer to LBA as linear block addressing.
Link
A way of providing multiple names to reference a single file. Links are created with the ln command.
Linux
The open source OS kernel originally developed by Linus Torvalds and since then maintained and expanded by a large team of programmers.
An OS based on the Linux kernel, particularly if it follows the Unix model. Most Linux OSs rely heavily on software from the GNU project, so some people prefer the term GNU/Linux.
Logical Partition
A type of MBR hard disk partition that has no entry in the primary partition table. Instead, logical partitions are carried within an extended partition.
Low-level formatting
Creating data structures on a disk that define the locations of individual sectors and tracks. Hard disks are low-level formatted at the factory and should not normally be low-level formatted by end users. Floppy disks may need to be low-level formatted by end users via the Linux fdformat command. See also high-level formatting.
Module
A kernel driver or other kernel component that’s stored in a separate file. Linux can load modules on demand or on command, saving RAM when modules aren’t in use and reducing the size of the kernel.
Module Stack
A set of modules that build up to provide some set of features. For instance, to deliver sound, you may need to load several sound driver modules that make up a module stack.
Mount
The process of adding a filesystem (meaning 1) to a directory tree.
A command of the same name that performs this task.
Mount point
A directory to which a new filesystem (meaning 1) is attached. Mount points are typically empty directories before their host filesystems are mounted.
Mounted
The status of a filesystem that has been linked to a directory tree using the mount command.
New Technology File System (NTFS)
The favored filesystem on Windows NT/200x/XP/ Vista systems. Linux supports NTFS, but this support is limited.
NTFS
The favored filesystem on Windows NT/200x/XP/ Vista systems. Linux supports NTFS, but this support is limited.
OHCI
A common hardware standard for managing USB 1.x ports.
Open host controller interface (OHCI)
A common hardware standard for managing USB 1.x ports.
Parallel ATA (PATA)
The traditional form of ATA interface, in which several bits are transferred at once. See serial ATA (SATA).
Partition
An arbitrary region of a storage device (almost always a hard drive) created by partitioning software before data were stored. Specifically on IBM PC-compatibles: one of up to four distinct areas on a hard drive which can be dedicated to different operating systems. One of the partition types, “extended”, supports further “partitioning” into a maximum of four logical disks.
PATA
The traditional form of ATA interface, in which several bits are transferred at once. See serial ATA (SATA).
PCI
An expansion bus capable of much higher speeds than the older ISA bus. Modern computers usually include several PCI slots.
Peripheral Component Interconnect (PCI)
An expansion bus capable of much higher speeds than the older ISA bus. Modern computers usually include several PCI slots.
Plug and Play (PnP)
A set of hardware standards enabling automated, or at least software-based, configuration of hardware. This term applies mostly to ISA devices, although PCI and other devices are sometimes described as being PnP devices.
PnP
A set of hardware standards enabling automated, or at least software-based, configuration of hardware. This term applies mostly to ISA devices, although PCI and other devices are sometimes described as being PnP devices.
POST
A series of basic hardware checks performed by the motherboard’s firmware when the computer is first powered on and before the boot loader or OS boots. The POST can detect some, but not all, serious hardware problems before the OS boots.
Power-on self -test (POST)
A series of basic hardware checks performed by the motherboard’s firmware when the computer is first powered on and before the boot loader or OS boots. The POST can detect some, but not all, serious hardware problems before the OS boots.
Primary partition
A type of MBR partition that’s defined in a data structure contained in the hard disk’s partition table in the MBR. MBR is limited to four primary partitions per hard disk.
RAM
Volatile, writable memory that a computer uses as its main memory. Comes in flavors like EDO, ECC, SDRAM, etc. which are not equivalent but from the perspective of a sysadmin are very similar under normal use. See ROM.
Random access
A method of access to a storage device (RAM, hard disk, and so on) by which information may be stored or retrieved in an arbitrary order with little or no speed penalty. See sequential access.
Real-time clock (RTC)
A type of clock maintained by a running Linux system and used by most software programs that must refer to the time. See hardware clock.
ReiserFS
One of several journaling filesystems for Linux. Developed from scratch for Linux.
Rock Ridge
A set of extensions to the ISO-9660 filesystem that enable storage of Unixstyle long filenames, ownership, permissions, and other filesystem features on an ISO-9660 filesystem. See also ISO-9660 and Joliet.
RTC
A type of clock maintained by a running Linux system and used by most software programs that must refer to the time. See hardware clock.
SATA
A type of ATA interface that uses serial data transfer rather than the parallel data transfers used in older forms of ATA. See also parallel ATA (PATA).
SCSI
An interface standard for hard disks, CDROM drives, tape drives, scanners, and other devices.
Second Extended File System (ext2fs or ext2)
The most common filesystem (meaning 1) in Linux from the mid-1990s through approximately 2001.
Serial ATA (SATA)
A type of ATA interface that uses serial data transfer rather than the parallel data transfers used in older forms of ATA. See also parallel ATA (PATA).
Small Computer System Interface (SCSI)
An interface standard for hard disks, CDROM drives, tape drives, scanners, and other devices.
Swap partition
A disk partition configured to be used as swap space.
Swap space
Disk space used as an extension to a computer’s RAM. Enables a system to run more programs or to process larger data sets than would otherwise be possible.
Terminated
In the context of SCSI devices, refers to the presence of a resistor pack that prevents signals from bouncing back from the end of a SCSI chain. The devices on both ends of a SCSI chain must be terminated, but other devices must not be terminated.
Third Extended File System (ext3fs or ext3)
A variant of the Second Extended Filesystem (ext2 or ext2fs) that adds a journal to reduce startup times after a power failure or system crash. See also journaling filesystem.
UDF
A next-generation optical disc filesystem, frequently used on DVD-ROMs.
UHCI
A common hardware standard for managing USB 1.x ports.
Universal Disc Format (UDF)
A next-generation optical disc filesystem, frequently used on DVD-ROMs.
Universal Host Controller Interface (UHCI)
A common hardware standard for managing USB 1.x ports.
USB
USB is a protocol and hardware port for transferring data to and from devices. It allows for many more (and varied) devices per interface port than either ATA or SCSI and gives better speed than RS-232 serial and parallel ports.
USB hub
A piece of hardware that enables connecting multiple USB devices to a single USB connector on a computer.
XFS
One of several journaling filesystems for Linux. XFS was developed by Silicon Graphics (SGI) for its IRIX OS and then ported to Linux.
