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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2
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1answer
24 views

Changing the /dev/tty* permissions at startup

My solution (ArchLinux ARM on RaspberryPi) requires that a non-privileged user has to have access to the /dev/ttyAMA0 port. In final implementation that user will be automatically logged in and a ...
4
votes
1answer
39 views

why isn't monitor listed under /dev in linux?

If /dev is suppose to list all the devices that is connected, like usb, hdd, webcam, how come on my ubuntu 15 VM I don't see a monitor? I am running the desktop edition so there should be a monitor. ...
3
votes
3answers
238 views

USB device to be detected at the “same” /dev point always?

In Linux (actually I'm with CentOS v6.5), whenever I plug in my USB Terminal/Character Device (some kind of USB Adapter) for the first time (after booted), it is detected at: /dev/ttyUSB0 But ...
1
vote
1answer
711 views

Can I use a parallel port as a CUPS input device?

I have an old piece of a hardware that does diagnostics on medical equipment. It prints out results over a parallel port. Is there any way to have CUPS accept jobs from a parallel port and redirect ...
5
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4answers
3k views

Prevent claiming of novelty usb device by usbhid so I can control it with libusb?

I have a USB rocket launcher that I wish to experiment with through libusb. However, libusb cannot claim the interface; presumably because the output of usb-devices lists 'usbhid' as the driver for ...
0
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0answers
13 views

Platform Device Drivers

I was just going through the code of kernel. I have a raspberry Pi board. I want to interface the touch screen with my board. I want to develop the Platform driver for that. As per the documentation ...
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0answers
4 views

Discrepancy in Owncloud drive size

I have ownCloud running on Debian Raspberry Pi with an 8Gb USB as the drive. Checking the USB is mounted correctly: df -h /dev/sda1 7.3G 20M 6.9G 1% /media/owncloud But my ownCloud Mac ...
3
votes
1answer
33 views

How do I check if sound card is in use and, if possible, which process is using it?

I want to know if a program is using my sound card without my knowledge. I thought about building a program that uses low-level device driver code to do the trick, but am now interested in seeing if I ...
8
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3answers
6k views

How can I tell whether a network interface is physical (device) or virtual (alias)?

I have a small home router running OpenWrt (Kind of embedded Linux for routers). It has five Ethernet ports, one labeled WAN and four labeld LAN 1 to 4. It has the following Network Interfaces defined ...
0
votes
1answer
638 views

What are high level and low level device drivers

Recently I read that there are two types of drivers (at least for disk), one that are called high level drivers and another called low level device drivers. Can some one tell me what these are, and ...
2
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2answers
38 views

How do I recreate /dev/ttyUSB## devices that I deleted?

Background It seems I only know enough linux to get myself in trouble. I'm working on a couple of embedded systems (two different models) both running linux. I've been troubleshooting a modem ...
1
vote
1answer
30 views

How to associate physical usb port with usb device number

I'm using Ubuntu 12.04. I need to send a command to a device that I have connected on a port of my PC. I can send the command by finding out what the Bus and Device number are. For example, lsusb ...
2
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1answer
63 views

mmap /dev/random

Why is it that I cannot mmap /dev/random or /dev/urandom on Linux? I get errno 19 which is ENODEV. When I try the same code with /dev/zero it works. int fd = open(path, O_RDONLY); assert ...
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0answers
17 views

Playing sound through /dev/dsp?

I have a USB soundcard attached to my Raspberry Pi. I used the command: sudo modprobe snd_pcm_oss which created /dev/dsp and /dev/dsp1. /dsp corresponds to the internal soundcard whereas /dsp1 ...
0
votes
1answer
27 views

Lvreduce online on RHEL 6 or centos 6 with ext4 file systems

Is it possible to reduce a mounting lv safely at RHEL6/CentOS6 with ext4 file system? If it is, how can I do that?
3
votes
2answers
1k views

Debian USB automount

Got my USB flash automount broken after reboot. Using Debian 6, GNOME 2 My NTFS hard disk is still mounting correctly. When i connect my Android smartphone (with SD and local drive) my messages log ...
1
vote
1answer
23 views

OSX: MBP: How does system detect sd card inserted?

I have a MacBookPro running Mavericks. I can insert one sd card into the slot and it mounts just fine. Another sd card I slip in and nothing happens. It does not appear in disk utility. It does ...
1
vote
1answer
2k views

Why is my Mac, upgraded from Mavericks to Yosemite, no longer giving VMware Fusion needed resources?

I have a Mac upgraded from Mavericks to Yosemite. When I tried to run VMware Fusion, I got an error stating: Could not open /dev/vmmon: No such file or directory. Please make sure that the kernel ...
6
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2answers
56 views

Can a linux filesystem be backed up by copying the file structure tree only?

This might be considered to be more of an academic question but here goes. Returning to Linux after some years away, I installed Ubuntu 15.04 Desktop on a small PC. Looking around the file system ...
0
votes
1answer
34 views

How to get a list of major number -> driver associations

http://www.nostarch.com/tlpi states: "Each device driver registers its association with a specific major device ID, and this association provides the connection between the device special file and the ...
1
vote
0answers
57 views

USB bar code scanner not working on Raspbian

My USB bar code scanner (SYMBOL LS2208) is recognized as a HID. hid-generic 0003:05E0:0600.000F: hiddev0,hidraw0: USB HID v1.10 Device [\xffffffef\xffffffbe\xffffffa9\xffffffbe\xffffffa9Symbol ...
7
votes
1answer
7k views

How to Reset/Cycle Power to a PCIe Device?

I have a PCIe device that only works correctly when the computer is fully powered off then on again. Issuing a simple reboot or reboot -p command does not appear to cycle the power to the PCIe card, ...
2
votes
1answer
68 views

Capturing data from a Fluke 1620a via Bash /dev/tcp file descriptor

I am currently trying to develop a script that will connect to a Fluke DewK 1620a Themo-Hygrometer and pull the current temperature and humidity readings from the device. While these devices have a ...
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0answers
83 views

LVM unknown device: how to recover?

I have a server with two hard drives that I thought I had correctly installed with LVM, until I discovered that the second hard-drive did not actually seem to be used. I investigated the problem and ...
36
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4answers
4k views

Why are network interfaces not in /dev like other devices?

I'm mostly curious, but why aren't network interfaces in /dev? Are there any other kinds of devices that aren't represented as a node under /dev?
2
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1answer
36 views

Why can X11 access the video card?

This one is maybe a bit theoretical, but... How the heck can X11 touch the video hardware? As I understand it, X11 is an unprivileged user-mode program. But only kernel-mode software can access the ...
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0answers
31 views

FreeBSD: Permanent nodes for usb devices

In FreeBSD, USB devices appear in /dev as (for example) /dev/ugen2.5, /dev/ugen2.6, etc... However, I noticed after a reboot sometimes these are pointing to different devices. Is there a way to lock ...
2
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0answers
28 views

Why reading from and writing to framebuffer shows no effect ?

I read a very short description of how to make a Screenshot by making use of the file which represents the framebuffer /dev/fb0. in order to write the screen content: cat /dev/fb0 > file in ...
3
votes
3answers
728 views

How to know if /dev/hda2 is Primary partition or Extended partition

If all four primary partitions exist on an IDE drive, they are numbered as follows: /dev/hda1 /dev/hda2 /dev/hda3 /dev/hda4 We have also the partitions on a disk with one primary partition and ...
4
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2answers
434 views

Using bash's `/dev/udp`, how would I know if the port was open?

I do not have access to netcat or nmap so I'm trying to use bash and the /dev/udp/ special files to test ports. I could do something like: echo "" > /dev/udp/example.com/8000 But $? is always 0 ...
0
votes
1answer
37 views

Sunix Low Level Parallel port driver not working

Background: I am currently in the process of updating a Industrial PC + software from Debian 4 (etch) to Debian 7 (Wheezy) due to hardware obsolescence, one of the few pieces of hardware being shared ...
1
vote
1answer
39 views

Can you scp a device file?

My flash is partitioned as /dev/mtd0 /dev/mtd1 etc....And I want to scp one of the partitions over to my pc so I can analyze it with a hex editor, but everytime I try to copy it with scp I get -not a ...
0
votes
1answer
38 views

Debian Fresh Install: IO_Page_Fault

I recently tried to install Debian alongside the mint installation I am using to type this. However, I keep getting this strange error whenever I try to boot it, even after a fresh install ...
2
votes
1answer
166 views

Why is “nodev” in /etc/fstab so important? How can character devices be used for hacking?

I am learning about linux security and struggling to understand why a USB stick with a character device on it is potentially dangerous. If I have a USB stick with a bash executable that has setuid ...
1
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0answers
46 views

Suse 10 - Same disk showed as IDE (hda) and SCSI (sda)

I have a strange problem with disk detection. I installed a Suse 10 and I see the same disk (scsi) showed as /dev/hda and /dev/sda. Here the fdisk output: sl0slmkmsd00:~ # fdisk -l /dev/hda Disk ...
1
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0answers
61 views

Bluetooth keyboard not showing up in /dev/input

I've just installed an Apple Wireless keyboard on a Debian system. I used this guide and only console tools — no X on that machine yet. The keyboard works fine. Now I want to remap a right Cmd key ...
1
vote
1answer
779 views

Why isn't sda1 showing up in dev and how can I fix that?

I have an embedded Linux device and I was trying to copy some files to it. I plugged in a USB stick, the dmesg shows that it was recognized, but for some reason /dev/sda1 never showed up. I'm trying ...
0
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0answers
69 views

No USB flash drive / dev / Galileo Intel Gen2

I have intel Galileo Gen2 and Debina installed on it from here: http://sourceforge.net/p/galileodebian/wiki/Home/ And I also have a problem with that, it does not appear in the / dev / any of the usb ...
12
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4answers
5k views

If I connect a physical device, how can I ever know which device file belongs to it?

Say I plug in several USB drives which don't get automatically mounted. How can I find out which device file belongs to which physical device, so I can mount it for example? I'm running Mac OS X but ...
-1
votes
1answer
30 views

Which of the following is a Linux representation of a physical USB device?

I'm trying to figure out which of these could be a physical USB device: /dev/hda /dev/hda1 /dev/bin /dev/sda /dev/sda2 What's the difference between hda and sda? Between hda and hda1? Which could ...
2
votes
0answers
30 views

How to temporarily disable mouse device?

I have wireless USB keyboard and mouse combo. I need a way to disable mouse while leaving keyboard function working and a way to enable it again after some time. I don't use X and I can't make it in ...
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0answers
32 views

Pipe a device via USB or wlan

I have an Android phone and I want to use some of its onboard device from PC. To be more clear, there is a node in /dev/ and I want to have on PC a file (or named pipe which is accessable as a file) ...
0
votes
1answer
26 views

How to figure out primary/secondary IDE channel via sysfs (if possible)

Though I've got quite a good basic understanding of sysfs meanwhile, there are still things I cannot solve on my own. For a starter, I'd like to figure out via sysfs (later by scripting of course) ...
0
votes
1answer
135 views

RHEL7: Why does 'nmcli conn show' & 'ip addr show' display different connections?

My 'nmcli conn show' & /'etc/sysconfig/network-scripts' config files don't match up, showing just one connection/devices of each: [root@ciroc network-scripts]# ls |grep ifcfg ifcfg-enp0s3 ...
1
vote
1answer
65 views

Run Out Of Space On /dev/sda2

My Linux (Mint 13) laptop reported that 'The volume "Fiilesystem root" has only 0 bytes disk space remaining'. When I ran a 'df' I got the following result:- HP-255-G1-Notebook-PC # df Filesystem ...
4
votes
1answer
329 views

Why did sshd delete my /dev/zero?

When I do lsof +c 0 | grep /dev/zero, I see the following two lines: sshd 19064 root DEL REG 0,4 497862 /dev/zero sshd 19064 root DEL REG 0,4 498725 /dev/zero ...
1
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1answer
1k views

Beaglebone Black Device Tree for LCD4 cape

The device tree for LCD4 cape is located at /lib/firmware/BB-BONE-LCD4-01-00A1.dts When I looked into it, the declaration of those GPIO buttons confuse me. There are five buttons according to ...
0
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0answers
24 views

Detecting and categorizing device drivers in a running system

How can I obtain what device drivers are incorporated in a running kernel? More than this, how can I categorize these device drivers? For instance, this is a Linux kernel conceptual map, from ...
2
votes
1answer
183 views

What are the two values in < > in a device tree .dts file?

Following is the code snippet in a device tree file: flash@0 { compatible = "n25q128"; reg = <0x0>; spi-max-frequency = <50000000>; ...
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0answers
50 views

Is the device tree compiler tied to the kernel version?

I have a situation in which same device trees are used with different kernels. Can the device trees be build only once and used with all kernels? The reason I ask this is because I found the device ...