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57
votes
18answers
168k 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
229 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
70 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 ...
3
votes
1answer
93 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*.
1
vote
1answer
56 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 ...
0
votes
0answers
99 views

Editing a device tree to disable driver loading

Below is a section of device tree. ps7_ethernet_0: ps7-ethernet@e000b000 { #address-cells = <1>; #size-cells = <0>; ...
2
votes
1answer
935 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 ...
3
votes
1answer
1k 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
83 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 ...
3
votes
1answer
572 views

Is there a way to change device names in /dev directory?

I wrote this rule for testing purpose: SUBSYSTEMS=="usb", ATTRS{manufacturer}=="Kingston", ATTRS{serial}=="001CC0EC34A2BB318709004B", ATTRS{idVendor}=="0951", ATTRS{idProduct}=="1642", ...
5
votes
3answers
2k views

Mounting a device — role of /dev, /media and /mnt, and the mount command [closed]

I have several closely related questions about what happens when I insert a CD. The files on the CD /media/Ubuntu\ 11.04\ i386/, but from what I've seen /dev/cdrom is also involved. What is the ...
5
votes
1answer
874 views

Difference between /dev and /sys/class?

What is the difference between the device representation in /dev between the one in /sys/class? Is one prefered over the other? Is there something one offers and the other doesn't?
3
votes
2answers
2k views

Unable to find root device / sda partitions missing

I have installed Archlinux, and after that GRUB. I manually entered menu entries for both my Windows and Arch installation. GRUB has no problems booting, and can successfully load in Windows. It ...
1
vote
2answers
68 views

What is a device tree and a device tree blob?

What exactly is a device tree, and a device tree blob? Where can I get its source code for a particular linux version? I found such name while running linux on xilinx chips (having ARM 9), for ...
6
votes
1answer
2k 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 ...
19
votes
3answers
1k views

mv a file to /dev/null breaks dev/null

If I do: touch file; mv file /dev/null as root, /dev/null disappears. ls -lad /dev/null results in no such file or directory. This breaks applications which depend on /dev/null like SSH and can be ...
0
votes
1answer
87 views

Confusion about group `cdrom` in linux system

When I type command groups ubuntu, the output would we like, ubuntu : ubuntu adm dialout cdrom floppy audio dip video plugdev netdev admin I am interested in the cdrom group. What does the group ...
1
vote
0answers
28 views

Execute command when mouse is pluged/unpluged on GNU/Linux

Is it possible to have something like event handler for plugging unpluggig a mouse in Unix System? I want to have a script that will enable/disable touchpad but not only on startup (you can find ...
6
votes
1answer
659 views

USB connect/disconnect notification

I use Linux Mint 13 MATE, and I'm trying to set up notifications when I plug/unplug devices. First of all, I found udev-notify package, but unfortunately it almost doesn't work for me: it works for ...
2
votes
0answers
297 views

Fedora unable to detect USB or wireless networks? [closed]

I installed Fedora(Gnome) 19 on a Dell Inspiron with Intel i3 processor, and a factory built-in Windows 7 home premium OS. The installation process completed successfully. But now when I log into ...
1
vote
0answers
65 views

Mount partition with truecrypt using the commandline

I'm trying to mount a encrypted HDD with truecrypt, but I cann't find the device. Where can I finde my HDD and what is the command to mount it in truecrypt? I'm using Raspbian on Raspberypi.
0
votes
2answers
623 views

Allow non-root user to read/write /dev files

In my /dev folder, I would like the following files to be user readable and writable: /dev/ttyUSB0 /dev/gpib0 How do I do this without using chgrp? I can edit /etc/udev/rules.d but I do not know ...
1
vote
1answer
83 views

Getting message “Error trying to open /dev/dvd exclusively” at the end of a DVD burning process when using growisofs

I am using Linux Fedora Core 4 (have to work with a legacy system) and trying to burn DVDs as a non-root user using the growisofs utility. I seem to be getting this error message at the end of the ...
1
vote
1answer
54 views

Disable emulated scroll wheel (EmulateWheel) for specific programs

Is it possible to disable evdev's EmulateWheel option when using specific programs? In my use case, I would like to be able to interact with the Acme text editor and with some VMs using my Thinkpad's ...
0
votes
0answers
182 views

Debian 7.3 - Nautilus doesn't show devices and partitions in left panel after changing partitions

Today I changed some partitions (moving, resizing) on my second hard drive and after restarting Debian I noticed that Nautilus doesn't show either partitions nor removable devices in left panel. In ...
1
vote
1answer
82 views

Permission of DVD device file not being retained when machine is rebooted

I am using Linux Fedora 4 and would like a non-root user to be able to write to DVDs using the DVD drive. I was able to do this by adding write access to the group of the device file /dev/scd0 and ...
1
vote
0answers
53 views

Create a fake read only device like file with incrond

I need to generate UUID with uuidgen (not through any function call, but external command, because processes which will read the file cannot call any APIs or external commands directly). My idea is ...
3
votes
1answer
142 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 ...
2
votes
1answer
58 views

What happens under the hood when some data is sent/received on an uart (or similar)?

I am trying to understand how computers work and I was thinking about peripherals. Here is what I understand so far but some parts are missing. Using an Arduino, I send some text every second (a then ...
8
votes
3answers
5k views

what is stored in /dev/pts files and Can we open those?

I am curious to know that what is stored in /dev/pts/ files . Can we open those files ? According to my knowledge /dev/pts files are created for ssh or telnet session .
3
votes
2answers
95 views

Is there a uniform way to discover information about devices?

UPD: Changed question title from manage devices to discover information about devices One of the frequent thing I do is look up info about devices on my systems. And I am constantly find myself ...
4
votes
1answer
8k 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 ...
32
votes
3answers
3k 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?
0
votes
1answer
148 views

Using USB hub for keyboard and mouse in multiseat

I want to configure a 2 user multi-seat in Linux. Is it possible to configure keyboard and mouse for second seat with a USB hub on a single USB port or I need to connect each of them to a separate USB ...
3
votes
1answer
2k views

Change the number of generated /dev/tty devices

I'm building an embedded Linux system, based on Gentoo. Using udev, all tty devices are probed with a PROGRAM stanza to determine if they are a modem. Right now the system boots up with 64 /dev/tty*. ...
0
votes
1answer
162 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 ...
0
votes
1answer
173 views

How to debug a device that changes from /dev/ttyUSB0 to /dev/ttyUSB1 at will?

I have a device plugged to a CentOS server that changes randomly from /dev/ttyUSB0 to /dev/ttyUSB1 and vice versa. The device I'm trying to connect is this one. How can I debug this?
3
votes
3answers
8k views

GSM modem does not create /dev/ttyUSB file

I installed Kannel in a server, and I want to use a GSM 3G USB modem to send/receive SMS messages, as described in section SMS Centers > GSM Modem of the Kannel User Guide. I have already installed, ...
1
vote
1answer
376 views

Difference between Device file and device drivers

I am beginner in device driver programming. I don't get the difference between device drivers and device files in Linux. Can anyone explain the difference?
0
votes
0answers
323 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 ...
4
votes
2answers
475 views

How to take sha-1, sha-256 or MD5 of CDs / DVDs?

I just tried burning both a Debian CD and a Debian DVD from their .iso files and I've got a weird behavior: the checksum of the CD is correct but the one of the DVD ain't. Here's what working: ...
3
votes
5answers
3k views

GNU/Linux (Debian): detecting hard-disks mappings?

Let's suppose you have two hard-disks: one internal (boots GNU/Linux); one external (USB). "fdisk -l" detects both, but will not tell you which is /dev/sda and which is /dev/sdb. "lsusb" will tell ...
1
vote
1answer
98 views

2 or more programs in same USB serial converter

Having a network of lets say 10 devices in RS-485, connected to the linux PC with a RS-485 to USB Converter. Already there is a C program interacting with the serial converter at /dev/ttyUSB0. My ...
1
vote
0answers
68 views

Which Unixes support cross-device filesystem links (in particular for rename)?

Just read the following on the FreeBSD man page for the rename syscall: ... [EXDEV] The link named by to and the file named by from are on different logical devices (file systems). Note that ...
4
votes
2answers
128 views

Can you identify transport via sysfs?

I'm writing a script, and I'm interested in being able to identify the transport class (fc - "fibre channel", scsi, iscsi, etc.) for a given block device. I can retrieve this information via ls -l ...
2
votes
0answers
381 views

Debian Wheezy USB2 ehci_hcd

I have a friend who decided to switch to Linux from Windows. I was helping her to get up and running as quickly as possible but we ran into a problem which I can't seem to solve. She uses Debian ...
3
votes
2answers
175 views

Permissions to print directly to USB printer

I've a netbook with Linux. I've a usb/serial printer and I added the line chmod 666 /dev/tty* to rc.local and it prints straight after a reboot. When I close the lid of a netbook for a while and then ...
1
vote
1answer
224 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, ...
2
votes
0answers
97 views

How to rename devices for graphical output such as VGA0

On my Laptop the names of my graphical outputs change depending on what chip is activated in the BIOS. This leads to problems in some scripts where outputs such as VGA-0 or LVDS-0 are specified. So I ...
3
votes
2answers
909 views

Can I stop Linux from listening to a USB input device as a keyboard, but still capture events with a program?

I have a USB barcode scanner at /dev/input/event0 (/dev/input/by-id/usb-Metrologic_Metrologic_Scanner-event-kbd), and scanning a barcode causes it to send keypress events. I'm capturing these ...