What is a character device?
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I was trying to make a partition on my USB drive when I came across some files/entities in /dev/ which seemed unfamiliar (such as hidraw2). When I opened /dev in file manager and looked into their properties, it says that they are character devices. While searching about them, I came across posts that explain what 'block devices' are, but no such post for character devices so far.
I would like to know what a character device is and what it does. Also I wonder about why they are called devices.
usb files filesystem
asked Apr 2 at 18:44
NurShomik
515
add a comment |Â
up vote
7
down vote
favorite
I was trying to make a partition on my USB drive when I came across some files/entities in /dev/ which seemed unfamiliar (such as hidraw2). When I opened /dev in file manager and looked into their properties, it says that they are character devices. While searching about them, I came across posts that explain what 'block devices' are, but no such post for character devices so far.
I would like to know what a character device is and what it does. Also I wonder about why they are called devices.
usb files filesystem
asked Apr 2 at 18:44
NurShomik
515
1
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30
add a comment |Â
up vote
7
down vote
favorite
up vote
7
down vote
favorite
I was trying to make a partition on my USB drive when I came across some files/entities in /dev/ which seemed unfamiliar (such as hidraw2). When I opened /dev in file manager and looked into their properties, it says that they are character devices. While searching about them, I came across posts that explain what 'block devices' are, but no such post for character devices so far.
I would like to know what a character device is and what it does. Also I wonder about why they are called devices.
usb files filesystem
asked Apr 2 at 18:44
NurShomik
515
I was trying to make a partition on my USB drive when I came across some files/entities in /dev/ which seemed unfamiliar (such as hidraw2). When I opened /dev in file manager and looked into their properties, it says that they are character devices. While searching about them, I came across posts that explain what 'block devices' are, but no such post for character devices so far.
I would like to know what a character device is and what it does. Also I wonder about why they are called devices.
usb files filesystem
usb files filesystem
asked Apr 2 at 18:44
NurShomik
515
asked Apr 2 at 18:44
NurShomik
515
asked Apr 2 at 18:44
NurShomik
515
asked Apr 2 at 18:44
NurShomik
515
asked Apr 2 at 18:44
NurShomik
515
515
1
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30
add a comment |Â
1
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30
1
1
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
10
down vote
accepted
This is a simple explanation:
- A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, octets).
- A Block ('b') Device is one with which the Driver communicates by sending entire blocks of data.
- Examples for Character Devices: serial ports, parallel ports, sounds cards.
- Examples for Block Devices: hard disks, USB cameras, Disk-On-Key.
- For the user, the type of the Device (block or character) does not matter - you just care that this is a hard disk partition or a sound card.
- Driver programmers, however, do care.
Here is more:
16.1.4.2 Block and Character Devices
A block device is one that is designed to operate in terms of the block I/O supported by Digital UNIX. It is accessed through the buffer cache. A block device has an associated block device driver that performs I/O by using file system block-sized buffers from a buffer cache supplied by the kernel. Block device drivers are particularly well-suited for disk drives, the most common block devices.
A character device is any device that can have streams of characters read from or written to it. A character device has a character device driver associated with it that can be used for a device such as a line printer that handles one character at a time. However, character drivers are not limited to performing I/O a single character at a time (despite the name ``character'' driver). For example, tape drivers frequently perform I/O in 10K chunks. A character device driver can also be used where it is necessary to copy data directly to or from a user process. Because of their flexibility in handling I/O, many drivers are character drivers. Line printers, interactive terminals, and graphics displays are examples of devices that require character device drivers.
Sources:
http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html
https://arstechnica.com/civis/viewtopic.php?t=787631
edited Apr 2 at 19:37
wjandrea
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
10
down vote
accepted
This is a simple explanation:
- A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, octets).
- A Block ('b') Device is one with which the Driver communicates by sending entire blocks of data.
- Examples for Character Devices: serial ports, parallel ports, sounds cards.
- Examples for Block Devices: hard disks, USB cameras, Disk-On-Key.
- For the user, the type of the Device (block or character) does not matter - you just care that this is a hard disk partition or a sound card.
- Driver programmers, however, do care.
Here is more:
16.1.4.2 Block and Character Devices
A block device is one that is designed to operate in terms of the block I/O supported by Digital UNIX. It is accessed through the buffer cache. A block device has an associated block device driver that performs I/O by using file system block-sized buffers from a buffer cache supplied by the kernel. Block device drivers are particularly well-suited for disk drives, the most common block devices.
A character device is any device that can have streams of characters read from or written to it. A character device has a character device driver associated with it that can be used for a device such as a line printer that handles one character at a time. However, character drivers are not limited to performing I/O a single character at a time (despite the name ``character'' driver). For example, tape drivers frequently perform I/O in 10K chunks. A character device driver can also be used where it is necessary to copy data directly to or from a user process. Because of their flexibility in handling I/O, many drivers are character drivers. Line printers, interactive terminals, and graphics displays are examples of devices that require character device drivers.
Sources:
http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html
https://arstechnica.com/civis/viewtopic.php?t=787631
edited Apr 2 at 19:37
wjandrea
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
add a comment |Â
up vote
10
down vote
accepted
This is a simple explanation:
- A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, octets).
- A Block ('b') Device is one with which the Driver communicates by sending entire blocks of data.
- Examples for Character Devices: serial ports, parallel ports, sounds cards.
- Examples for Block Devices: hard disks, USB cameras, Disk-On-Key.
- For the user, the type of the Device (block or character) does not matter - you just care that this is a hard disk partition or a sound card.
- Driver programmers, however, do care.
Here is more:
16.1.4.2 Block and Character Devices
A block device is one that is designed to operate in terms of the block I/O supported by Digital UNIX. It is accessed through the buffer cache. A block device has an associated block device driver that performs I/O by using file system block-sized buffers from a buffer cache supplied by the kernel. Block device drivers are particularly well-suited for disk drives, the most common block devices.
A character device is any device that can have streams of characters read from or written to it. A character device has a character device driver associated with it that can be used for a device such as a line printer that handles one character at a time. However, character drivers are not limited to performing I/O a single character at a time (despite the name ``character'' driver). For example, tape drivers frequently perform I/O in 10K chunks. A character device driver can also be used where it is necessary to copy data directly to or from a user process. Because of their flexibility in handling I/O, many drivers are character drivers. Line printers, interactive terminals, and graphics displays are examples of devices that require character device drivers.
Sources:
http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html
https://arstechnica.com/civis/viewtopic.php?t=787631
edited Apr 2 at 19:37
wjandrea
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
add a comment |Â
up vote
10
down vote
accepted
up vote
10
down vote
accepted
This is a simple explanation:
- A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, octets).
- A Block ('b') Device is one with which the Driver communicates by sending entire blocks of data.
- Examples for Character Devices: serial ports, parallel ports, sounds cards.
- Examples for Block Devices: hard disks, USB cameras, Disk-On-Key.
- For the user, the type of the Device (block or character) does not matter - you just care that this is a hard disk partition or a sound card.
- Driver programmers, however, do care.
Here is more:
16.1.4.2 Block and Character Devices
A block device is one that is designed to operate in terms of the block I/O supported by Digital UNIX. It is accessed through the buffer cache. A block device has an associated block device driver that performs I/O by using file system block-sized buffers from a buffer cache supplied by the kernel. Block device drivers are particularly well-suited for disk drives, the most common block devices.
A character device is any device that can have streams of characters read from or written to it. A character device has a character device driver associated with it that can be used for a device such as a line printer that handles one character at a time. However, character drivers are not limited to performing I/O a single character at a time (despite the name ``character'' driver). For example, tape drivers frequently perform I/O in 10K chunks. A character device driver can also be used where it is necessary to copy data directly to or from a user process. Because of their flexibility in handling I/O, many drivers are character drivers. Line printers, interactive terminals, and graphics displays are examples of devices that require character device drivers.
Sources:
http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html
https://arstechnica.com/civis/viewtopic.php?t=787631
edited Apr 2 at 19:37
wjandrea
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
This is a simple explanation:
- A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, octets).
- A Block ('b') Device is one with which the Driver communicates by sending entire blocks of data.
- Examples for Character Devices: serial ports, parallel ports, sounds cards.
- Examples for Block Devices: hard disks, USB cameras, Disk-On-Key.
- For the user, the type of the Device (block or character) does not matter - you just care that this is a hard disk partition or a sound card.
- Driver programmers, however, do care.
Here is more:
16.1.4.2 Block and Character Devices
A block device is one that is designed to operate in terms of the block I/O supported by Digital UNIX. It is accessed through the buffer cache. A block device has an associated block device driver that performs I/O by using file system block-sized buffers from a buffer cache supplied by the kernel. Block device drivers are particularly well-suited for disk drives, the most common block devices.
A character device is any device that can have streams of characters read from or written to it. A character device has a character device driver associated with it that can be used for a device such as a line printer that handles one character at a time. However, character drivers are not limited to performing I/O a single character at a time (despite the name ``character'' driver). For example, tape drivers frequently perform I/O in 10K chunks. A character device driver can also be used where it is necessary to copy data directly to or from a user process. Because of their flexibility in handling I/O, many drivers are character drivers. Line printers, interactive terminals, and graphics displays are examples of devices that require character device drivers.
Sources:
http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html
https://arstechnica.com/civis/viewtopic.php?t=787631
edited Apr 2 at 19:37
wjandrea
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
edited Apr 2 at 19:37
wjandrea
7,18342255
edited Apr 2 at 19:37
wjandrea
7,18342255
edited Apr 2 at 19:37
wjandrea
7,18342255
7,18342255
answered Apr 2 at 19:01
George Udosen
17.2k93761
answered Apr 2 at 19:01
George Udosen
17.2k93761
answered Apr 2 at 19:01
George Udosen
17.2k93761
17.2k93761
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
add a comment |Â
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Thanks for response. This clearly explains both block and character devices.
– NurShomik
Apr 2 at 19:59
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
Your welcome @NurShomik!
– George Udosen
Apr 2 at 20:11
add a comment |Â
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1
Also, The hidraw driver provides a raw interface to USB and Bluetooth Human Interface Devices (HIDs).
– AbraCadaver
Apr 2 at 20:30