The devices tag has no wiki summary.
1
vote
1answer
43 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 ...
3
votes
0answers
37 views
What kernel module function gets called, when I say “cat myfile > /dev/sda” [migrated]
I've skimmed through the Linux Kernel Module Programming guide, but can't figure out:
When I say cat image.iso > /dev/sda, will it cause the write function of file_operations structure to be ...
1
vote
1answer
326 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 ...
0
votes
0answers
45 views
How to install driver for my Intel series PC
I installed Linux on an Intel Panel PC. Jockey cannot detect any drivers. I do not know how to install my graphics driver first so that I am be able to install touch screen.
Here's some info from ...
3
votes
3answers
65 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 ...
1
vote
2answers
49 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
72 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?
2
votes
0answers
38 views
How to know when a device is ready
I have firewire mixing console and I wrote an udev rule which calls a script to set up the whole audio chain (alsa -> pulseaudio -> jackd -> firewire) as soon an the console is switched on.
Now I ...
2
votes
1answer
76 views
Creating eth0 with consistent network device naming
From my understanding, Arch Linux uses Consistent Network Device Naming where the network devices are no longer named eth0, eth1, etc. I use the proprietary MATLAB software which requires a device ...
3
votes
2answers
47 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 ...
3
votes
2answers
57 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?
4
votes
1answer
88 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, ...
1
vote
1answer
91 views
A drive changes device file name after resuming from suspend (Linux Mint 14)
I'm running into a very odd problem: When I resume Mint 14 from suspend, one of my drives (/dev/sdc) changes letter / device file name (to /dev/sdd). fdisk -l shows that it has the same partitions, ...
4
votes
2answers
48 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 ...
3
votes
1answer
2k 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 ...
5
votes
2answers
229 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 ...
3
votes
2answers
101 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 ...
8
votes
2answers
1k 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, ...
0
votes
0answers
33 views
programming an Atmel Board with a USB to Serial converter, in Eclipse
I am actually trying to program an Atmel Evk1100 board directly from Mac OSX.
My MCU is UC3A0512
I used to use Atmel32 Studio on Windows, but It looks like there no Mac Version.
So, from what I've ...
2
votes
1answer
57 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
vote
0answers
43 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 ...
1
vote
2answers
36 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?
0
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0answers
18 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
2k 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
78 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
...
2
votes
2answers
96 views
Why doesn't xsetwacom work from udev?
I made a script to rotate my Wacom Bamboo tablet 180 degrees. It works fine when I execute it as myself (user) or root, but when started from udev (i.e. when plugging the tablet into a usb port) it ...
0
votes
2answers
41 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
66 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 ...
3
votes
1answer
277 views
Writing /dev/random to file?
If you ran the following, what would happen?
cat /dev/random > ~/randomFile # don't run
Would it be written until the drive runs out of space, or would the system see a problem with this and ...
0
votes
1answer
200 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?
16
votes
4answers
6k 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 ...
3
votes
1answer
216 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
141 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 ...
14
votes
2answers
998 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:
...
2
votes
0answers
84 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
48 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
252 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 ...
23
votes
7answers
45k views
How do I find out what hard disks are in the system?
I need to know what hard disks are available, including ones that aren't mounted and possibly aren't formatted. I can't find them in dmesg or /var/log/messages (too much to scroll through). I'm hoping ...
0
votes
2answers
91 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
81 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
3k 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 ...
2
votes
2answers
295 views
Why are there so many virtual terminal devices?
I've been reading the advanced linux programming book availalble free online linky and it mentiones about virtual terminals which if I understood it correctly it is a Linux specific feature (not in ...
0
votes
2answers
863 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?
12
votes
3answers
1k 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.
2
votes
0answers
165 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
83 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:
# ...
7
votes
2answers
454 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 ...
2
votes
2answers
615 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 ...
8
votes
3answers
2k 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" > ...
3
votes
1answer
1k views
/dev/sdb: No such file or directory (but /dev/sdb1 etc. exist)
I'm not sure what is wrong here but when running fdisk -l I don't get an output, and when running
fdisk /dev/sdb # I get this
fdisk: unable to open /dev/sdb: No such file or directory
I'm ...
