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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6
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1answer
1k views

Find out if a specific device is an USB mass storage

Context I'm automating SD card imaging from an existing dd factory image. The SD card is always connected through an external USB card reader and thus appears in the system as a SCSI block device ...
0
votes
2answers
773 views

Cheap 100% Debian compatible ultrabooks [closed]

I'm looking for relatively cheap ultrabooks with 100% Debian compatible features. I have several ultrabooks on my list but they contain some additional features which i don't need (additional ...
2
votes
1answer
2k views

“PS/2 Generic Mouse” gets lost. How to reload without reboot?

I am running Ubuntu 12.04LTS on a ThinkPad E420s. My Trackpoint is recognized as "PS/2 Generic Mouse". My problem is that it doesn't load/disappears after booting or after suspension. I can't move ...
1
vote
0answers
602 views

Check if Keyboard and Mouse are plugged in

Is there a way to detect if a keyboard and a mouse is plugged in (and working) in Linux? This will be embedded in a PXE setup, so I only have Kernel + Modules and Busybox available. Bonus question: ...
5
votes
2answers
347 views

Can I query which processes (if any) are currently accessing the microphone?

I'm running Debian (technically Raspbian), trying to get a Star-Trek style voice-command system. I've got it mostly up and running, but in the interests of privacy and all that jazz, I don't want my ...
2
votes
1answer
87 views

Assigning static device path

I have 4 flash cards plugged in, sequentially named by system: /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 I want to assign static pathes to them, so every time the system boots up their pathes will ...
1
vote
2answers
192 views

/dev/console points to tty0?

I've been trying to understand the /dev/console device, but there are a few things I'm not clear on: What is the purpose of this device? From what I can gather it's just a place for the kernel to ...
2
votes
1answer
462 views

open() console for default file descriptors

I'm reading a shell program implementation in C ( the xv6 shell from MIT's 6.828 Operating System Engineering course ). The main() function for this shell starts with the following code: //Assumes ...
-1
votes
1answer
296 views

what type of device drivers are available in linux [closed]

The different types of device drivers used in linux are character device and block device. Is there another classification?
2
votes
2answers
247 views

Detecting the device of a crypto mount

I have an external eSATA-hdd on an OpenSUSE 12.2 system. The external hdd has an LVM on a dm-crypt partition. I mount it by powering it up and then doing rescan-scsi-bus.sh cryptsetup -v luksOpen ...
9
votes
1answer
8k views

using devtmpfs for /dev

I have noticed the following option in the kernel: CONFIG_DEVTMPFS Device Drivers -> Generic Driver Options -> Maintain devtmpfs to mount at /dev And I see that it is enabled by default in ...
1
vote
1answer
3k views

pvcreate error on partition

I can't create this partition, I'm getting this error shown below: Device /dev/mapper/vg_paperino-lv_rootp1 not found (or ignored by filtering) Below are the steps that I'm doing on CentOS: ...
1
vote
1answer
496 views

Creating a terminal device for interprocess communication

I'd like to know how to create a terminal device to simulate a piece of hardware connected through a serial port. Basically, tty device with a certain baud rate that can be read from and written to ...
1
vote
1answer
639 views

Installing a platform driver

I have recently acquired a device driver for an integrated watchdog timer on a x86 board on which I am running a minimal Linux system. The kernel is 3.6.11 and it has been built using buildroot. My ...
3
votes
2answers
405 views

Why doesn't `head -c 2 /dev/hwrng` work?

I have an Atmel 97SC3201 in my computer and set the following in the kernel: CONFIG_HW_RANDOM_TPM CONFIG_TCG_TPM CONFIG_TCG_ATMEL /dev has tpm0 and hwrng, but running this command returns the ...
5
votes
3answers
7k views

RHEL: Creating stable names for network interfaces

We have a RHEL 5.5 box with 8 interfaces. And the eth interface naming is flip flopping. Sometimes eth0 comes up on physical port 7th, and sometimes on another physical port. We want the naming to ...
3
votes
2answers
327 views

Automated partition selection in bash script

I'm trying to write a bash script to run from Linux on a CD or flashdrive that can mount Windows and change stuff, but I don't know how to go about detecting which partition/drive is Windows. My best ...
5
votes
2answers
3k views

Linux : Major and Minor device numbers

What types of devices fall under the major device number category and what types of devices fall under the minor device number category. What is the real difference between the two categories?
7
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2answers
4k views

wlan number assignment

How or where does Linux determine the assignment of a network device? Specifically, wlan0 or wlan1 for wireless USB devices. I plugged in a TP USB wireless a while ago, and it was assigned wlan0. I ...
5
votes
1answer
3k views

Why do my SATA devices show up under /proc/scsi/scsi?

I have 3 SATA devices on my system. They show up under /proc/scsi/scsi, although these are not SCSI devices. Why do my SATA devices show up under the SCSI directory? $ cat /proc/scsi/scsi Attached ...
10
votes
2answers
8k views

set baud speed for tty

How do I set the baud speed for a specific tty (in this case a serial port)? I tried using stty -F /dev/tty.iap ispeed 19200 But get the error Invalid argument for every speed I try (2400, 4800, ...
2
votes
0answers
162 views

Block Devices & Partitions

I partitioned a microSD card (mmcblk1) into two partitions mmcblk1p1 and mmcblk1p2. If use a dedicated card reader I am able to see the entire SD card and its partitions using various disk management ...
0
votes
0answers
21 views

How to associate device to sata port disk [duplicate]

I have 2 hard disks connected to 2 sata ports. The disks are associated to /dev/sda and /dev/sdb. These hard disks are in software raid so it happens that the system can go for some time with only ...
1
vote
4answers
6k views

Updated Fedora 18 - no sound devices, just dummy output

So, yesterday I updated the recently released Fedora 18, this has been done: Packages Altered: Updated grubby-8.20-1.fc18.x86_64 @?fedora Update 8.22-1.fc18.x86_64 ...
2
votes
0answers
223 views

Webcam Device Driver to support H.264

I have a Creative Live Cam Connect HD (id: 041e:4093) and this webcam has an on-board H.264 encoder. Unfortunately v4l2 only inputs the feed as MJPG. $ v4l2-ctl --list-formats ioctl: VIDIOC_ENUM_FMT ...
0
votes
2answers
84 views

Changes to files don't show up until the partition is unmounted

I have a FAT32 filesystem mounted. After changing a file on it, I can read the file back and still see the old version. My changes don't actually persist until I unmount and remount the partition. Is ...
2
votes
1answer
141 views

What is the source of truth for currently active tty/pts connections?

I'm looking for a simple way to determine the number of currently logged in users, using only the filesystem and basic bash functions (instead of using binaries). The uptime binary appears to be ...
0
votes
1answer
734 views

remove /dev/mapper/fedora-root and /dev/mapper/fedora-swap

I want to replace Fedora 18 with Ubuntu but I have these devices listed when partitioning. I only have a hard disk labelled sda, where does these virtual device come from? How I do remove them?
29
votes
4answers
24k views

What is the mknod command used for?

I just started using Ubuntu as my main OS and I wanted to learn about things I should not do, and learn by the bad things people have done in the past. I came across these email about horror stories ...
5
votes
1answer
2k views

Query USB current

How can I obtain information about the amount of current negotiated by a device attached to a USB port? I am looking for information similar to this presented by OS X in terms of current available ...
0
votes
2answers
409 views

Problem mounting my iRiver story HD on Ubuntu

I would like to connect my iRiver Story HD to my ubuntu 12.04 machine but as I connect it I get this error: Unable to mount Story HD Error mounting: mount: wrong fs type, bad option, bad ...
15
votes
2answers
3k views

bash script to detect and record mouse movements?

I need to be able to record the mouse movements every so often (every .2 of a second for example) and have them in a coordinate representation instead of a diff. I found the following script: ...
3
votes
0answers
218 views

How to route one video device to multiple programs

I'd like to direct the output of a single capture card (Hauppauge PVR-150) to two programs: VLC (for streaming on LAN) and MythTV for scheduled recording. I think it's possible to do this with the ...
2
votes
1answer
99 views

Standard way to expose device file to userland applications running on an unprivileged user account?

I just finished the first version of a Linux kernel module I've written in C. The module creates a device file (/dev/wn0) that controls a USB device with three LED lights. For example, running as ...
5
votes
4answers
876 views

Testing, from a script, if audio devices are in silent?

Is there a default program where I can check if my audio devices are in silent? Edit: By silence, I mean that if there is something playing on that (not just activated or opened) Something like ...
0
votes
2answers
165 views

What files are being updated or written in /dev/sda?

root@host [/etc]# iostat -xk Linux 2.6.32-279.19.1.el6.x86_64 (host.superhostsite.com) 01/13/2013 _x86_64_ (24 CPU) avg-cpu: %user %nice %system %iowait %steal %idle ...
2
votes
0answers
206 views

Connected Android device - brings the network down?

I have dealt with sensitive development under Android, and have recently decided to switch to Linux now sit under (Mint 13 - KDE). But strangely, when the Android device is connected, my network goes ...
4
votes
2answers
10k views

ttyUSB0 permission changes after restart

I'm trying to install a device. I plug in the device which creates a ttyUSB0 file. When I open it in the program I need it for, it says the permission is denied. I type in terminal sudo chmod 666 ...
13
votes
2answers
17k views

What are character special and block special files in a unix system?

How are character special files and block special files different from regular files in a Inix-like system? Why are they called “character special” and “block special” respectively?
15
votes
3answers
3k views

Monitor what is being sent to /dev/null?

Just for fun: Is there a way to monitor/capture/dump whatever is being written to /dev/null? On Debian, or FreeBSD, if it matters, any other OS specific solutions are also welcome.
6
votes
0answers
675 views

How do I let an SDL app (not running as root) use the console

I want to use an SDL-based program to display graphics on the console, without having to log on from the console, and without running the program as root. For example, I want to be able to run it via ...
2
votes
2answers
158 views

Why I have two /dev/sdx entries with a single disk?

In my laptop (running Linux) I have only one SSD, connected to the SATA3 port. Why I have two sdx entries in /dev directory? In particular I see /dev/sda and /dev/sdb, and /dev/sda is the SSD: # ...
4
votes
2answers
4k views

Prevent usbhid from claiming USB device

Directly related: Prevent claiming of novelty usb device by usbhid so I can control it with libusb? I want to access an RFID reader (works as HID device) from a program that uses libusb-0.1. In the ...
9
votes
3answers
7k views

Mount printers at /dev/usb and still use CUPS

Due to a new version of CUPS, I suddenly lost the direct path to my printers that was previously available under /dev/usb/lpXXX. I used this to print directly from the command line. echo "test" > ...
6
votes
2answers
6k views

What causes /dev/disk/by-label to be populated?

I've noticed that Linux distributions typically have a /dev/disk/by-label directory, but this isn't always the case (For example, the CirrOS Linux test image doesn't have one). What's required on a ...
4
votes
0answers
2k views

How do I find out the device node corresponding to my device in SuSE 8?

I'm forced to work with a bunch of point-of-sale systems running SuSE 8. They are my client's computers. We are stuck dealing with these old systems until they get to upgrade their whole fleet to SLE ...
2
votes
1answer
668 views

Why are there symlinks in /dev? (LVM)

[root@SERVER ~] ls -la /dev/vg/root lrwxrwxrwx 1 root root 17 2012-10-28 10:29 /dev/vg/root -> ../mapper/vg-root [root@SERVER ~] QUESTION: Why are there symlinks? Why there couldn't be only 1 ...
3
votes
3answers
755 views

Disk size management

I am using Fedora 16. My /dev/sda2, mounted on / (root) with something like 50G got filled 100%: [foampile@~ 13:13:39]> df Filesystem 1K-blocks Used Available Use% Mounted on rootfs ...
3
votes
1answer
75 views

Is 'device' synonymous with 'drive' in Unix-like OS's?

In Unix/Linux terminology, are the words 'device' and 'drive' synonymous?
2
votes
1answer
333 views

Why slowusb and scandelay?

I'm running linux-3.4.9 compiled with genkernel, and booting from a USB HDD. I was slightly annoyed by the slow boot process, in particular, during the execution of genkernel scripts at the modprobe ...