The use of Unix in embedded computer systems such as networking equipment, mobile phones, media players, set-top boxes, etc.

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What are the minimum root filesystem applications that are required to fully boot linux?

It's a question about user space applications, but hear me out! 3 'applications', so to speak, are required to boot a funcitonal distro of Linux: Bootloader - For embedded typically that's U-Boot, ...
8
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3answers
644 views

Open Source router firmware options?

What distro's exist that are designed for routers? Please include the following link to the project page link to supported hardware list what distinguishes them, why pick this option friendly web ...
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1answer
3k views

Debian and Systemd: breaking ordering cycle error

I'm a new embedded developer I'm trying to make systemd 37 work with freescale vybrid board (A5 and M4) running on linux-3.0 After boot with some breaking ordering cycle error, I check with ps ...
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4answers
41k views

How to check password with Linux?

I want to check, from the linux command line, if a given cleartext password is the same of a crypted password on a /etc/shadow (I need this to authenticate web users. I'm running an embedded linux.) ...
10
votes
2answers
7k views

Attaching USB-Serial device with custom PID to ttyUSB0 on embedded

I'm attempting to get an FTDI USB-Serial device with a custom PID to automatically (or even manually) attach to ttyUSB%n, without much success. The device's normal VID/PID is 0403/6001. When ...
2
votes
1answer
269 views

Relative path to anything not working (while running from initramfs)

I'm working in an embedded Linux system trying to get it booting its root file system in ram using initramfs. The system comes up for the most part but then has trouble in the init scripts. I've ...
4
votes
3answers
945 views

Debugging ethernet before NFS boot

I'm trying to boot Linux from U-boot on an embedded ARM board using a filesystem on a remote machine served via NFS. It appears that the ethernet connection is not coming up correctly, which results ...
2
votes
1answer
268 views

What are the Linux shells that allow network traffic management (sending/receiving data to/from `/dev/tcp/host/port`) via redirectors?

Following this Bash tutorial, I have succeded in obtaining the code of a web page issuing simple commands by using this method: $ exec 3<>/dev/tcp/www.google.com/80 $ echo -e "GET / ...
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0answers
224 views

No network interface for the lan9118 emulated on QEMU 1.4.0 overo machine

Im using QEMU 1.4.0 Ubuntu 13.04 distribution. Im trying to make the virtrual machine part of the host network so Im ussing this command: sudo qemu-system-arm -M overo -m 1024 -sd ./test.img -clock ...
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2answers
4k views

Is using a read only root file system a good idea for embedded setup?

I have been tasked with running Linux as an operating system on an embedded device. The target has an x86 processor and has 8 GB CompactFlash device for storage. I have managed to use buildroot to ...
25
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5answers
7k views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
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2answers
9k views

How do I have Linux boot with a rootfs in RAM?

The rootfs is a squashfs image and my bootloader is loading it into some address in SDRAM. What parameters do I need to pass to the kernel so It can mount the rootfs from there? Squashfs support is ...
11
votes
2answers
4k views

Is it possible for a daemon (i.e. background) process to look for key-presses from a USB keyboard?

I'm working on an embedded Linux project where I will be developing a program that will run automatically on bootup and interact with the user via a character display and some sort of button array. ...
11
votes
5answers
1k views

Which minimal but extendable Linux distribution to choose

I need an extendable Linux distribution which I can easily reduce in size so much that it fits into a 64 mb CF card. In this stripped version it will run on a Via C7 and needed is Kernel, ...
4
votes
1answer
146 views

How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?

For an embedded Linux system, if I have two or more network interfaces, how do I ensure that they always get the same interface names every boot In other words, I want, for example, eth0 to always ...
8
votes
1answer
1k views

CLFS: Building GCC cross compiler

Currently I try to build a embedded Linux from scratch with the instructions from Cross Linux from Scratch. Everything worked fine until I tried to compile the GCC Cross-Compiler. I want to build the ...
5
votes
1answer
1k views

How to set the CPU freq. in Linux?

I'm using this ARM9 SAM9G25 embedded system, that when switched on, is only online for a few seconds and because I want to speed up the whole process, I'd like to check the CPU frequency, and set it ...
5
votes
1answer
346 views

How can I find the Secure Attention Key (SAK) on my system and can I disable it?

In answer to My process was killed but I cannot understand the kernel notice, I was pointed to some documentation on the Secure Attention Key (SAK) on Linux. I have a embedded system generated using ...
4
votes
4answers
424 views

How do I create small disk image with large partitions

I am building a disk image for an embedded system (to be placed on an 4GB SD card). I want the system to have two partitions. A 'Root'(200Mb), and a 'Data' partition(800Mb). I create an empty 1GB ...
3
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2answers
5k views

How do I cause a watchdog reset of my embedded Linux device

Is there a command like vi > out vi | out That I could use to cause a watchdog reset of my embedded linux device?
1
vote
1answer
4k views

/dev/console dynamic redirection

Is it possible to dynamically redirect all data sent to /dev/console into something else (for example - to /dev/null, /dev/tty9 or even /dev/null)? Of course, it can be done statically via ...
5
votes
3answers
1k views

Is making /etc directory read only a bad idea?

I have an embedded system setup built using buildroot and using initramfs. It runs on compact flash device where I have created separate ext3 partitions to mount /etc/ and /var directories as well as ...
5
votes
4answers
3k views

How do I install GCC on a system with no compiler?

I've been messing around with my NAS which runs on Linux. I have root access, but there is no compiler. I seem to remember something about being able to compile on another system, but I'm not certain. ...
4
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0answers
446 views

Confusion with how to restore corrupt ext3 files if power outage occurs during a file write

I am running a small embedded system. Because the system will never be gracefully shutdown and will just have the power cable unplugged, I am running an initramfs but mounting an ext3 partition on a ...
3
votes
1answer
2k views

How to custom build debian's busybox?

I'm building an embedded system based on debian 7, and I'd like to make the most out of busybox that comes with debian. The problem is default busybox build in debian seems quite minimal, for example ...
2
votes
1answer
860 views

How to connect to ssh-server running on embedded linux without /etc/passwd?

After installing ssh server on my remote machine (which runs embedded Linux), I tried to connect to ssh server from host machine but it failed. This is because I could not specify user account when ...
2
votes
1answer
885 views

lsmod returns nothing on my embedded device

I have put a vendor supplied embedded Linux installation (called X-Linux) onto a hardware device. I ran lsmod to see what modules are loaded and nothing at all is shown. Also there is no /proc/modules ...
2
votes
1answer
783 views

Good OpenWRT alternative? [duplicate]

Possible Duplicate: Open Source router firmware options? I own an ASUS wl-520gU (4 LAN, 1 WAN, WiFi, 1 USB, 4mb flash rom, 16mb ram. Broadcom BCM5354 @ 240). I am going to use it as a ...
1
vote
1answer
193 views

CLFS for ARMv7 neon

I am following CLFS book (GIT-20140613-arm version), and I have a issue when building GCC with armv7 and neon combination. Target info here. My host is a clean Debian 8 with gawk, build-essential, ...
1
vote
1answer
391 views

How to check my account on embedded linux without “/etc/passwd”?

On some embedded linux systems, there is no /etc/passwd file and /etc directory is not writable (which means I cannot set user account and password?). Then what is my (default) account name and ...
1
vote
1answer
481 views

Using ncurses for basic GUI on a process started inside an init script

I have a custom written application that runs on a embedded setup (buildroot). My application has to run every time the target device boots up and so I wrote an init script to do this and it works ...
1
vote
1answer
593 views

Unable to get embedded device to ping anything on the network

I have an embedded device, built using buildroot, kernel version 3.6.11 running busybox. The kernel is built with completely default options. I have configured the device according to what the network ...