Devices 2 Flashcards
Linux recognizes most optical storage drives as the SCSI devices ____, ____ and so on.
/dev/sr0
/dev/sr1
What are terminals?
Devices for moving characters between a user process and an I/O device, usually for text output to a terminal screen.
Where does the name terminal come from?
The terminal device interface goes back a long way, to the days when terminals were typewriter-based devices.
What are pseudoterminal devices?
Emulated terminals that understand the I/O features of real terminals, but rather than talk to a real piece of hardware, the kernel presents the I/O interface to a piece of software, such as the shell terminal window that you type most of your commands into.
Linux has two primary display modes. What are they?
text mode
X Window System server (graphics mode, usually via a display manager)
Although Linux systems traditionally booted in text mode, most distributions now use kernel parameters and interim graphical display mechanisms (_____ such as plymouth) to completely hide text mode as the system is booting.
bootsplashes
Unnecessary complexity in the kernel is dangerous because you can too easily introduce ________.
system instability
The kernel presents each partition as a ____________, just as it would an entire disk.
block device
Partitions are defined on a small area of the disk called a _____.
partition table.
There are many kinds of partition tables. The traditional table is the one found inside the ________. A newer standard starting to gain traction is the _______.
Master Boot Record (MBR)
Globally Unique Identifier Partition Table (GPT)
parted
a text-based tool that supports both MBR and GPT
gparted
a graphical version of parted
fdisk
the traditional text-based Linux disk partitioning tool. fdisk does not support GPT
gdisk
a version of fdisk that supports GPT but not MBR
The traditional MBR partition table is called _____ by parted
msdos
A filesystem is a form of database; it supplies the ______.
structure to transofrm a simple block device into the sophisticated hierarchy of files and subdirectories that users can understand.
Much as the SCSI subsystem standardizes communication between different device types and kernel control commands, Virtual File System (VFS) ensures that all _______.
all filesystem implementatoins support a standard interface so that user-space applications access files and directories in the same manner.
ext4
the fourth extended filesystem
The _________ was a longtime default for Linux systems inspried by traditional Unix filesystems such as the Unix File System (UFS) and the Fast File System (FFS0. The ______ added a journal feature (a small cache outside the normal filesystem data structure) to enhance data integrity and hasten booting. The ____ is an incremental improvement with support for larger files and a greater number of subdirectories.
second extended filesystem (ext2)
third extended filesystem (ext3)
fourth extended filesystem (ext4)
______ is a CD-ROM standard.
ISO 9660 (iso9660)
____ (msdos, vfat, umsdos) pertain to Microsoft systems.
FAT filesytems
What is HFS+?
HFS+ (hfsplus) is an Apple standard used on most Macintosh systems.
New Linux filesystems, such as ____, are under development and may be poised to replace the Extended series.
Btrfs
On Unix, the process of attaching a filesystem is called ______.
mounting
When the system boots, the kernel reads some configuration data and ___________.
mounts root (/) based on the configuration data.
If you run out of real memory, what can Linux do?
The Linux virtual memory system can automatically move pieces of memory to and from a disk storage.
What is it called when Linux virtual memory system moves pieces of memory to and from disk storage?
Swapping.
What is swapping?
Pieces of idle programs are swapped to the disk in exchange for active pieces residing on the disk.
The disk are used to store memory pages is called _____ or ____ for short.
swap space
swap
What is swap space?
The disk are used to store memory pages.
If you’re running many processess, it’s generally fine to swap out parts of inactive processes or even inactive pieces of active processes. However, if you’re constantly using the swap space because many active processes want to use the memory at once, _________.
you will suffer serious performance problems because disk I/O is just too slow to keep up with the rest of the system.
