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
553 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
656 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
73 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
280 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 ...
2
votes
2answers
767 views

Chroot Risks w/ /dev and /proc

I am planning to set up a few chroot jails for some users to run/test Java applications (lets just assume each application is untrusted). Is there any risk involved with mounting /dev and /proc into ...
9
votes
1answer
725 views

What happens when I do “cat debian.iso > /dev/sdX”?

I'm creating a live-USB and don't understand precisely: what happens when I copy a file (or even a file system) directly to a device node (as opposed to a file system)?
5
votes
1answer
150 views

Does the suid bit have any meaning for device files?

Does the suid bit have any special meaning for device files in Linux ?
3
votes
0answers
275 views

How to know the event by looking at /dev/input/by-id

I want to access the keyboard device driver. I usually accesses it by looking at /dev/input/by-name but the event provided by it gets changed every time I log in. After searchin on the Net, I found ...
4
votes
2answers
2k views

How does /dev/fd relate to /proc/self/fd/?

$ ls -l /dev/stdin /dev/fd/0 lrwx------ 1 tim tim 64 2011-08-07 09:53 /dev/fd/0 -> /dev/pts/2 lrwxrwxrwx 1 root root 15 2011-08-06 08:14 /dev/stdin -> /proc/self/fd/0 $ ls -l /dev/pts/2 ...
10
votes
1answer
6k views

Understand output of `udevadm info -a -n /dev/sdb`

I plug an external HDD into my laptop. I try to find out the information by $ udevadm info -a -n /dev/sdb Udevadm info starts with the device specified by the devpath and then walks up the chain of ...
3
votes
1answer
481 views

FreeBSD: Remove symlinks in devfs

Background I have been rebuilding a small home NAS. This server represents my first 'real' foray into the world of server administration and it has taught me quite a bit already. Originally, the ...
9
votes
1answer
890 views

What driver is behind a certain device file?

Given a device file, say /dev/sdb, is it possible to determine what driver is behind it? Specifically, I want to determine what driver my storage devices are using. fdisk -l lists 2 devices: /dev/sda ...
1
vote
1answer
350 views

Do I need ephemeral storage?

I was running a small instance on Amazon EC2. I'm trying to migrate it to a micro as it requires very minimal processing power. One thing I just learned though, is that micro instances do not come ...
2
votes
0answers
58 views

Limiting write rate of a device

How does one go about limiting the write/read rate of a device, E.G., USB drive, SD card? Motivation behind this question is covered here (superuser.com).
3
votes
2answers
463 views

Choosing a device name under /dev from the kernel command line

I am booting CentOS via a USB install. The boot method is simply booting the ISO from GRUB2 installed on the USB Key. The USB key always gets the "name" /dev/sda. Can I change that name from the ...
1
vote
0answers
104 views

“nopage” method for ISA vs PCI [closed]

This is with reference to LDD3 ch. 15, section "Mapping memory with nopage". I am having trouble understanding the third paragraph on page 429. It says: Note that this implementation works for ISA ...
2
votes
0answers
65 views

What are the differences between the current Linux kernel and the Unix SVR4 kernel in terms of device drivers+i/o and virtual files systems?

Yes I realize that Linux supports many more file systems and recognizes more devices than Unix SVR4. I'm interested in what the differences are in the abstraction on top of an actual file system, or ...
5
votes
1answer
395 views

Does the kernel delete entries in /dev on an initramfs?

I have a fully custom, minimal, embedded Linux (vanilla, 3.3.8, i486, Vortex86dx) system that boots from an initramfs image. No standard distribution scripts are used, just a single rcS file that does ...
1
vote
4answers
4k views

cfgmgr like command under Linux?

cfgmgr is a command under AIX/ksh that checks for new hardware; e.g. new HDD's that have been added without a shutdown. Question: Are there any similar commands under Linux? If "fdisk -l" doesn't ...
0
votes
1answer
272 views

Hidden ext4 partition?

Is there a way to hide an ext4 partition from e.g Thunar? And the open file/save dialog , I think they come from the same source.
3
votes
1answer
3k views

How can I uniquely identify which device is on USB `hub 6-0:1.0: port 2`?

How can I uniquely identify which device is on USB hub 6-0:1.0: port 2? I receive messages in my dmesg every now and then and I want the system to tell me which device is connected to that port. ...
5
votes
3answers
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 ...
10
votes
4answers
4k views

Can I setup a loopback audio device?

If I can send audio to the output devices, then I can record the same audio as a wave. With filesystems, you can just setup a loopback filesystem and write binary data on a file instead of a device. ...
3
votes
0answers
607 views

Build an Affordable Linux Tablet [closed]

I have 3 young children and my wife has asked that the girls get a tablet, for basic gaming, and online web tutorials (school work usually). Has anyone created or built a good affordable Linux ...
0
votes
0answers
137 views

problem exporting /media as an nfs share: why does it happen?

I've got two netbooks. One netbook has two installed Linux systems: openSUSE 11.04 and Debian testing. By default, in Debian, gnome mounts the /home filesystem for openSUSE, which shows up in gnome's ...
2
votes
1answer
224 views

Is there any way to control the light value of the Apple logo on a MacBook?

I'd like to mess around a bit with controlling the Apple logo on the outside of my MacBook Pro from Ubuntu. (I'd like to hook it up to my music and have it light up and down with the decibels :]) ...
1
vote
1answer
2k views

What's the difference between 'no caching page mode present' and 'assuming drive cache. write through.'

Post-POST, post-BIOS screen, post-GRUB; when I boot Debian with a SD card or USB stick plugged in, one of the first things to pop up on the screen (so quickly that usually I don't even notice) looks a ...
16
votes
2answers
3k views

Manipulating `/dev/video`

I'd like to take the video stream from /dev/video0, apply some effects or changes and make the result available on /dev/video1. /dev/video0 ---> Apply Effects ---> /dev/video1 For example, mplayer ...
2
votes
1answer
413 views

udev weirdness: /dev/hda1 mounted but file not present

I think my question is related to udev and/or udisks, but I am really not sure at all what's going on here. To start with, my system works more or less fine. The less part is due to the fact that, ...
23
votes
2answers
6k views

How to create /dev/null?

I successfully deleted my /dev/null. How can I restore it? The OS is Ubuntu.
5
votes
2answers
341 views

Unclaim a device

So I am using Ubuntu and trying to use some hardware which I had some problems with before. The problem before was that the company who made my hardware sold their internal parts to another company ...
0
votes
0answers
488 views

Silicon Wave USB Bluetooth Adapter doesn't work

I have been trying to use my usb bluetooth adapter(silicon wave) on ubuntu 11.10 server, it appears in the lsusb list but it doesn't work Bus 005 Device 003: ID 0c10:0000 root@i5-PC:/home/john# ...
0
votes
1answer
118 views

Applying an IO redirection&audio device example in Fedora

Here is an example I saw in a webpage which uses IO redirection to make the audio device make sound. less sound.wav > /dev/audio But I cannot do it in Fedora. It outputs the input data format is ...
11
votes
2answers
8k views

How do mouse events work in linux?

This is mostly out of curiosity, I'm trying to understand how event handling works on a low level, so please don't reference me to a software that'll do it for me. If for example I want to write a ...
4
votes
3answers
2k views

What do first column in /proc/mounts really mean in Linux?

Run cat /proc/mounts and I get this (simplified): rootfs / rootfs rw 0 0 proc /proc proc rw,relatime 0 0 /dev/sda1 / ext3 rw,relatime,errors=continue,barrier=1,data=ordered 0 0 io /etc/blkio cgroup ...
5
votes
3answers
644 views

How to get my USB key to auto mount

I'm currently working in a command line only environment. When I plug my USB key in, I see a new device file in /dev: ... sdi sdi1 ... If I simply sudo mount /dev/sdi1 /media/tmp, and umount it ...
3
votes
1answer
387 views

Vanishing permission on device file (RHEL 6.1)

I want to set world read/write permissions on a raw block device file (yeah, I know). I can set the permission to 666, but it goes back to 660 immediately after I touch it or write to it. Why? ...
23
votes
1answer
2k views

What do the device files in /dev actually do?

(Not a duplicate of Understanding /dev and its subdirs and files) I was browsing around my filesystem and for the first time I took a second to analyze my /dev directory. I was surprised by the ...
2
votes
1answer
1k views

How do I access a digital camera drive via usb after safely removing it?

In Ubuntu 11.04, I unwisely right clicked and "safely unmounted the drive" of my Sony HDR-XR150 connected via USB. Now, when I plug my digital camera into my computer via USB, Ubuntu either doesn't ...
1
vote
1answer
372 views

logical volume, logical disk, volume, partition, physical disk and filesystem

I was wondering how logical volume, logical disk, volume, partition, physical disk and filesystem are related and correspond to each other? I am confused about these concepts and would like to have ...
5
votes
2answers
2k views

Can I share a device from under /dev across hosts?

Here's the situation. I have a video device /dev/video0 on a VMware Server and I want to access this device from within a virtual machine. However for whatever reason I can't connect the device ...