devices refers to questions about the Unix/Linux device special files, normally these are under /dev. Do not use this tag for physical devices (for that use e.g. usb or pci).

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4
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2answers
83 views

How to run an application with certain group permissions?

I have a 3D printer, with which my PC can communicate through /dev/ttyACM0: crw-rw---- 1 root uucp 166, 0 16 nov 14:58 ttyACM0 The 3D printing application repetierHost requires read/write access ...
2
votes
1answer
479 views

create several /dev/xconsole files automatically upon boot

I understand from my previous question that the /dev/xconsole file can be created using mkfifo. On my system (Debian Wheezy), /dev/xconsole gets created automatically. I am wondering who creates it (...
2
votes
1answer
888 views

Is it possible to simulate/force/fake an USB device unplug and replug on Linux?

So I've got a strange problem that I've been running onto. I've got a bitcoin usb miner, Bitfury, and I'm using CGMiner to mine. When I start the application, as root, the USB device is not detected ...
5
votes
1answer
1k views

How to be notified when a USB device was plugged in?

My system has to auto-mount USB devices; how can I be notified when a USB device is plugged in? Where can I read more about this subject? I would like to handle this problem via C or a shell script.
4
votes
1answer
348 views

How to disable USB devices based on their vendor ID on GNU/Linux?

In that question someone wanted a blacklist for all USB devices, and then only allow specific devices. In this question, we want to accept all USB devices, but prevent the driver (e.g. cdc_acm) from ...
7
votes
2answers
10k views

How to grant non-root user access to device files

I have device file that appears in /dev when a specific board is plugged in. The read and write operations to it work just fine, but in order to open the device file the program needs to be executed ...
1
vote
1answer
319 views

talk to modbus device

I currently have a minimal install of Red Hat 6.5 running, on the machine I need to talk to a modbus device. I am wondering what tools and drivers are needed on a linux machine to talk to a modbus ...
3
votes
0answers
110 views

Bad/strange USB device issue: failed to shutdown/restart

On a fresh Arch Linux installation with Intel i7 processor and an Nvidia graphics card, I noticed during boot log messages related to a usb device filled the screen before it reached the graphical ...
6
votes
2answers
3k views

What happens if I run fsck on /dev/sda instead of /dev/sda1?

When I have run fsck in the past I have always run it on what I thought was a filesystem partition, ie. fsck -yf /dev/sdaN, where N is the partition number on disk A. A friend of mine recently ran ...
2
votes
0answers
223 views

How/where are linux device capabilities / bitfields set?

I have a device that has this output in /proc/bus/input/devices: I: Bus=0003 Vendor=05b8 Product=3280 Version=0111 N: Name="PixArt USB Optical Mouse" P: Phys=usb-0000:00:1a.0-1.1/input0 S: Sysfs=/...
1
vote
1answer
179 views

create several /dev/xconsole files

I am using /dev/xconsole to send system logs from rsyslog. That works great, because I am don't have to store the logs on disk. I would like to have another similar file , i.e /dev/xconsole1 where I ...
2
votes
0answers
463 views

How do you determine the capabilities of a WebCam?

I have a collection of WebCam's lying around. Some of them are new, some go back a decade (gotta love not having to "upgrade" devices in Linux :). Somehow I've developed the impression that ...
3
votes
1answer
1k views

cannot create special file /dev/pts/0

When using midnight commander in console, I cannot "toggle" the window (using CTRL-o Not an xterm or Linux console; the panels cannot be toggled however, my $TERM is set to linux. After some ...
1
vote
0answers
25 views

character device file (rtai_shm) disappears under runlevel=5 in fedora9 (exists when runlevel=3)

I am trying to run Realtime (RTAI) on my Linux Fedora 9 machine. For that, it is needed to have a character device file, named rtai_shm, in /dev, that takes care of shared memory. I have made this ...
0
votes
1answer
145 views

Determine driver for network interface [duplicate]

I wanted to see which driver was associated with some of the network interfaces listed by ip link. My first thought was to find the network interfaces in /dev and look at the device major and minor ...
1
vote
1answer
206 views

USB 3G dongle internet keeps failing on Fedora 20 laptop

I use a 3G dongle for internet in my summerhouse, it has worked fine all summer, but since yesterday it has been losing connection, or something and I have to unplug it and insert it again for the ...
4
votes
1answer
3k views

can not create /dev/shm

I need to create /dev/shm on an embedded ARM system. From "Installed The Latest Changes to Current and......". I see that it can be created with mkdir /lib/udev/devices/shm, but I'm wondering what ...
1
vote
1answer
685 views

How do I send RTSP video to a program that reads from a character device?

I have an IP-CAM that streams video over RTSP and I want to detect bar codes from it with zbarcam (from Ubuntu's zbar-tools package). According zbarcam's manual, it expects to be given a video4linux ...
1
vote
3answers
431 views

Looking at the content of a character device's file [duplicate]

Why is it possible to look at the contents of a block device's file like /dev/sda using cat or a hex editor? Why can I not do the same for a character device like /dev/pts/3?
2
votes
1answer
965 views

udev Unable to Rename Network Device: Device or Resource Busy

I'm trying to use udev rules in order to give my network interfaces static, consistent names. However, it seems like there is some race condition happening preventing these rules from consistently ...
3
votes
3answers
781 views

equivalent of `grep -a /dev/sda1` on Darwin?

I want to run something like % sudo grep -i -a 'some-string' <drive device> On Linux, <drive device> would be something like /dev/sda1. How can I find the equivalent on Darwin? (In ...
4
votes
2answers
425 views

Transfering content of block devices

For the purpose of backups, I'd like to transfer (several) whole disk partitions over an ssh link. So the source is a block special device, and the target should be a regular file. Common tools seem ...
5
votes
1answer
2k views

look up the device from its tty file?

Here is from my Ubuntu $ ls /dev/*tty* /dev/tty /dev/tty17 /dev/tty26 /dev/tty35 /dev/tty44 /dev/tty53 /dev/tty62 /dev/ttyS12 /dev/ttyS21 /dev/ttyS30 /dev/tty0 /dev/tty18 /dev/tty27 ...
2
votes
0answers
413 views

/dev/sda not appearing after secure erase

I decided to wipe my SSD with a secure erase before installing Arch Linux, since the Arch wiki said that it would improve performance. I followed the instructions listed on the wiki, but now when I ...
12
votes
2answers
4k views

What’s the difference between a “raw” and a “cooked” device driver?

Does this concept only apply to terminal drivers (which is what most sites cover) or to any driver in general?
4
votes
1answer
5k views

Map physical USB device path to the Bus/Device number returned by lsusb

I need to get the title of the attached USB device. I can do that with lsusb. udev allows some substitutions when I write rules: say, we can use $kernel to get name of the device, or $devpath to get ...
2
votes
1answer
77 views

PCI header in my laptop looks different from free-electrons' PCI header

I'm trying to develope a pci driver but I can not compile it because my pci header is quite different from books and references. My distribution is 3.15.7-1-ARCH. http://lxr.free-electrons.com/source/...
7
votes
3answers
5k views

Why won't Linux let me play with /dev/dsp?

I'm working through a Linux textbook, and it's telling me about devices. It says that if I send the appropriate output to /dev/dsp, then it will play a sound. The example is cat file.wav > /dev/...
6
votes
1answer
375 views

Does Posix require any devices?

Does Posix require any devices? For example, /dev/urandom, /dev/zero or /dev/null? I suspect not because of non-*nix OSes, but wanted to ask for completeness.
4
votes
2answers
410 views

How to programatically detect when a device raises an interrupt?

How to programatically detect when a device raises an interrupt? This can be when a device is connected or disconnected. And also this case: for example: when a finger is held over a fingerprint ...
3
votes
1answer
397 views

Why does the SELinux filesystem have it's own null device?

Looking through /sys/fs/selinux, I found this: # ls -l /sys/fs/selinux/null crw-rw-rw-. 1 root root 1, 3 Jan 24 02:47 /sys/fs/selinux/null Which is identical to /dev/null: # ls -l /dev/null crw-rw-...
8
votes
1answer
3k views

Explain EV in /proc/bus/input/devices data

Can anybody explain to me what the EV value in /proc/bus/input/devices is? The keyboard always has value 120013. Why?
1
vote
2answers
713 views

Perform an action when a wireless keyboard is connected

I need to perform a command when I connect a bluetooth keyboard. How can I 'listen' this event?
1
vote
0answers
71 views

Hotplug Device Driver Priority

Is it possible to have more than one driver for one purpose (eg. USB) included in the Linux kernel? If so, then how does the kernel decide which one to load?
2
votes
1answer
2k views

Prevent USB storage from using different device on reset

I have a hard drive in a USB enclosure that I am doing some data recovery on. The drive is in extremely bad shape and frequently resets on reads. The device registers as /dev/sdb. Sometimes, probably ...
1
vote
1answer
36 views

console (driver) not opening using any of the editor

In my initramfs, I have; [root@xilinx Peta_Microzed_15_05]# ls initramfs/dev/ console [root@xilinx Peta_Microzed_15_05]# nano initramfs/dev/console [root@xilinx Peta_Microzed_15_05]# The above ...
12
votes
4answers
11k views

Shell command to read device registers?

On a single-board computer running Linux, is there a way to read the contents of the device configuration registers that control hardware? I think it would be a wrapper for inw(), more or less. I'm ...
3
votes
1answer
258 views

Can renaming a network device cause race conditions?

Arch uses predictable network interface names. MATLAB licenses are linked to the MAC address of eth0, so I need to rename one of my devices eth0. In a machines with only one NIC I can just turn off ...
3
votes
2answers
526 views

PCI configuration registers problem

I'm trying to get my new Realtek RTL-8169 NIC (over CardBus) to work, but I'm having this weird problem. My lspci -x output looks like this: [root@comp]# lspci -x -d *:8169 07:00.0 Non-VGA ...
0
votes
1answer
125 views

Two Linux Mint 16 systems Skyping--one can see both parties on webcam, the other can see neither

I installed Linux Mint 16 32-bit edition on my netbook and a friend's laptop. When we Skype, I can see her live image, and I can see my own live image, so everything looks and sounds right on my end. ...
4
votes
2answers
2k views

what is the difference between Device driver and kernel module

i know that driver is a software that can communicate with the hardware in order to control the device that attached to the computer.whereas kernel module is a small piece of code that can inserted ...
2
votes
2answers
341 views

Check if a drive has been Zeroed with xxd and uniq?

I'm looking for a way to check if the entire binary contents of a USB device are purely 0s. I'm trying this command: sudo xxd /dev/sdb | uniq but it has no output and just runs forever. I've ...
13
votes
2answers
21k views

How does cat know the baud rate of the serial port?

I regularly use cat to view debugging information in the console from my FPGA development board over the serial connection, but I never have had to tell linux what the baud rate is. How does cat know ...
0
votes
2answers
4k views

Can I change devices permissions with chmod?

Before read: I don't want to use any udev rule. I need to change (programmatically) the permissions of some device. But first in order to underestand what I have to do (in code) I want to make the ...
2
votes
0answers
235 views

Debian - cannot find cdrom

Having a jessie/sid debian box on kernel 3.13 (had same issue on kernel 3.10) First thing I notices was that k3b didn't find any optical drives. Then: The optical drives (dvd-writers) are found in ...
4
votes
1answer
2k views

How to get address of connected USB modem?

I just connected my N81 telephone as USB modem to Linux Mint 14. All works fine, just wondering how to find a full path to this device, something like /dev/tty*.
2
votes
1answer
396 views

Why does RTC device have 254,0 instead of 10,135 as Major,Minor numbers?

Why isn't /dev/rtc the well known "c 10 135" device that it's on x86, but a magic undocumented "c 254 0" device? Devices.txt lists this major number as LOCAL/EXPERIMENTAL USE. I'm working on a ...
3
votes
1answer
3k views

Unable to use busybox implementation of hwclock

I have a buildroot generated kernel (3.6.11) and root file system running on an x86 device. It uses busybox and I am trying to set the BIOS hardware clock using hwclock. I get this error whenever I ...
4
votes
1answer
5k views

How creation of new USB device file in /dev/bus/usb/001/ directory work?

I noticed that every time I connect a USB device, a new device gets created in the /dev/bus/usb/001/ directory. Further on each reconnection of the same device, the "Device Number" and "ID" change. ...
1
vote
0answers
249 views

Why is my embedded Linux unable to detect the sd device?

I have this ARM9 SAM9G25 embedded System, running a Linux 2.6.39 Kernel and a Busybox. I put the Images (of the bootloaders, and the linux+initramfs) on a SD so that in the end the system is booting ...