Bootloader issues: what happens before the operating system itself starts.

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24
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5answers
16k views

Why does Linux allow ‘init=/bin/bash’?

I recently found out that if I edit GRUB before booting and I add rw init=/bin/bash I end up with a root shell. Being in a condition that I want to understand everything I would like to know why this ...
23
votes
5answers
15k views

SSH to decrypt encrypted LVM during headless server boot?

When I installed Ubuntu 10.04 and, now, 10.10, I was offered the option of enabling "encrypted LVM" for my hard drive. After choosing that option, I am prompted for my password during boot to decrypt ...
14
votes
3answers
43k views

How can I make a script in /etc/init.d start at boot?

I think I read something a while back about this, but I can't remember how it's done. Essentially, I have a service in /etc/init.d which I'd like to start automatically at boot time. I remember it ...
14
votes
5answers
17k views

What is the difference between LILO and GRUB?

I am running a web server under Debian and I currently have GRUB installed. Should I consider using LILO instead of GRUB? And what are the advantages of each?
14
votes
1answer
1k views

Rebooting without shutting off?

I have been using Linux Mint Debian with Debian unstable and noticed that when I press restart, instead of going all the way back to the BIOS, then grub, then booting up, I seem to be shutting down ...
13
votes
5answers
540 views

Why do most distributions chain UEFI and grub?

Most distributions install a additional boot loader on an UEFI system. UEFI itself is a boot loader, it offers a menu to select different operating systems or individual kernels. Furthermore, the UEFI ...
13
votes
4answers
7k views

How can I avoid “Run fsck manually” messages while allowing experimenting with system time changes?

I'm working with a system where we want to allow users to play around with the date and time if they want, and where reboots may happen arbitrarily. This is fine, except for one thing: if there's a ...
12
votes
4answers
14k views

How do I boot from a liveusb using qemu-kvm?

I am trying to get qemu-kvm to boot from my live usb stick. Is this possible?
12
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4answers
3k views

discribe in details tha boot process of any linux system

I am preparing a document in detail showing light on the boot sequence of Linux right from pressing of Power-on button the host to the login prompt appearance. It would be great if we could combine ...
12
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2answers
23k views

CentOS eth0 not starting

Why would my new CentOS Virtual Machine not start eth0 on startup? I have to start it manually every time. How can I fix this? Thanks.
10
votes
4answers
24k views

How to boot Linux to command-line mode instead of GUI?

I am using 32-bit Red Hat Linux in my VM. I want to boot it to command-line mode, not to GUI mode. I know that from there I can switch to GUI mode using startx command. How do I switch back to ...
10
votes
1answer
6k views

How can I test the RAM for data corruption on an ARM-based system?

I have an embedded device. It is ARM based, with Linux 2.6.31 and has 256 MB RAM. I wanted to get some ideas/tips on what is the most effective way to test the device RAM for data corruptions. Is ...
10
votes
5answers
12k views

Stop program running at startup in Linux

How do I stop a program running at startup in Linux. I want to remove some apps from startup to allow them to be managed by supervisord e.g apache2
10
votes
2answers
4k views

Why can't I specify my root fs with a UUID?

My system boots OK with this in my GRUB 2 config: linux /bzImage root=/dev/sda2 init=/usr/lib/systemd/systemd ro But if I replace /dev/sda2 with the corresponding UUID: linux /bzImage ...
10
votes
2answers
549 views

Removing abstraction from Ubuntu boot process

I have been using Linux after almost 5 years and observed that boot process has been almost abstracted. I mean, not much is visible to the user what is going on behind the scenes (Due to splash ...
10
votes
1answer
188 views

Why would a partition be in use by the system if it isn't mounted?

I've been migrating my system from btrfs to ext4 after running into performance issues with VMs. I have two hard drives in my laptop to work with. I've successfully moved my home partition, but the ...
9
votes
1answer
2k views

Relationship of keyboard layout and xmodmap

I'm using Xubuntu. Before login I can choose a keyboard layout. I'm using xmodmap for remmaping some keys. I'm interested in two things: How the state of keyboard mapping changes when I turn the ...
9
votes
2answers
2k views

What is Arch Fallback in Arch boot menu?

What is exactly "Arch Fallback" in the Arch boot menu?
9
votes
2answers
334 views

“Grep breaks, causing the boot process to hang forever”

Question within a question (from the Debian wiki): Should I use sid on my desktop? If you think you can handle a broken Debian system, sure. Do you know what to do if libpam0g breaks, ...
9
votes
1answer
4k views

Creating a bootable Linux installation USB without unetbootin

I want to install Scientific Linux from USB. I don't know why unetbootin doesn't work but I am not curious to find out: after all, I transferred to Linux from Windows to see and learn the underlying ...
9
votes
2answers
717 views

What is needed for a minimal systemd boot to launch getty on a virtual console?

For SysV init, I need /etc/inittab respawning getty entries, the /sbin/init binary, the binaries and shared libraries for the shell, login, the getty, the PAM/security/shadow stuff, and a few device ...
8
votes
2answers
8k views

Bash Script on Startup? (Linux)

Is there any way to make/run a bash script on reboot (like in Debian/Ubuntu for instance, since thats what my 2 boxes at home have) Also, any recommended guides for doing cron jobs? I'm completely ...
8
votes
1answer
589 views

Does Linux still have to reside within the first XX cylinders of a HDD?

It's been a while since I last bothered with partitioning my hard drive, but now it's time again and I remember last time I did this there was a requirement to put the root partition (or only GRUB?) ...
8
votes
5answers
6k views

Is it possible to put root in LVM without using initrd?

I have just set up a Gentoo base system (which means I can boot and log in and do stuff with it now). My root partition is in an LVM2 virtual group (with a separated /boot partition). In order to boot ...
8
votes
1answer
3k views

Load Linux bzImage in QEMU?

I compiled a Linux by doing make menuconfig then make and now I have compiled the most recent version of Linux. How can I load the kernel into QEMU?
8
votes
1answer
24k views

Booting linux from usb using EFI

I need to use a USB drive as an installation media for my Mint and Ubuntu. For that I have unetbootin to make the usb bootable. But my PC only supports EFI boot (while adding the boot device, I need ...
8
votes
1answer
4k views

Enable num-lock as default in Linux

There has been a similar question - but IMHO there has to be a simpler solution. If num-lock is on in the BIOS - why is it turned off during linux boot and/or KDE/Gnome/whatever startup?
8
votes
3answers
9k views

How to install GRUB to a whole ext4 disk without partition table?

Currently I have the entire disk /dev/sda formatted as ext4, and installed Gentoo. (There is no MBR, no partition at all. ) But finally, I can't install GRUB on it, because it seems like GRUB needs ...
8
votes
3answers
5k views

How to get rid of the “scanning for btrfs file systems” at start-up?

After upgrading from Ubuntu 12.04 to Ubuntu 12.10, I get a message "scanning for btrfs file systems" at starting-up. I don't have any BTRFS filesystem. It delays the booting for about 15 seconds. How ...
8
votes
1answer
351 views

Encrypted Booting

I want to boot the Linux from the /boot partition, and also want to encrypt this /boot partition. [ AFAIK, Grub is unable to find the kernel and initrd from an truecrypted partition or cryptsetup ...
8
votes
3answers
2k views

How should I configure grub for booting linux kernel from a USB hard drive?

I have a laptop hard drive in an external enclosure which I use as a large pendrive. For an added twist, I have installed Linux on it, so I can boot any machine with my distribution of choice (e.g. ...
7
votes
3answers
4k views

No space on device when removing a file under OpenSolaris

While trying to mount a NFS share (exported from an OpenIndiana server) on a client box, the OI server crashed. I got the black screen of death, what looked like a log dump, then the system restated. ...
7
votes
2answers
2k views

How to know if I'm booting using UEFI

I was searching, but didn't found an obvious way to know if GRUB is using UEFI in the system boot, or the BIOS compatibility mode or a full fledged BIOS. Only Windows methods. Is there something in ...
7
votes
3answers
1k views

What happens after loading the linux kernel image into RAM

I just to want to know the flow of activities happening after loading the linux kernel image into the RAM after boot process.
7
votes
2answers
19 views

Looking at the source files, where does Linux start executing?

I would like to read a bit of the source code to try and understand how it all fits together, but cannot see where to start. Which file in the Linux source code is the main file used to compile the ...
7
votes
3answers
3k views

Why does initramfs mount the root filesystem read-only

What is the reason for the root filesystem being mounted ro in the initramfs (and in initrd). For example the Gentoo initramfs guide mounts the root filesystem with: mount -o ro /dev/sda1 /mnt/root ...
7
votes
2answers
12k views

How to check on which drives grub2 has actually installed an MBR?

I'm on a Debian/Squeeze system (with a history going back to at least Woody) which was upgraded to grub2 as part of the Squeeze upgrade. All works well, but I'm about to mess with the disk ...
7
votes
1answer
2k views

How can you schedule a computer to boot at a specific time?

Usually BIOSes have an option to schedule a time to which to boot at. Is there a Unix/Linux interface to specify the scheduled boot?
7
votes
4answers
402 views

How to list all the files used during Linux boot

I would like to get the list of files that are used during the process of Linux boot. We are developing the protected enterprise system based on the RHEL 6.4. The integrity of specified files will be ...
7
votes
1answer
472 views

How is /etc/fstab accessed before root is mounted?

I was making some changes to /etc/fstab, when this chicken and egg question occurred to me - if /etc/fstab contains the instructions for mounting the file systems, including the root partition, then ...
7
votes
3answers
12k views

How to set global environment variables at boot through a script, and have them available for an application that runs before login?

I have a service that runs at boot, and in that service it calls a bash script in the background that exports some environment variables. The problem I'm having is that those environment variables ...
7
votes
1answer
2k views

booting qemu/kvm directly from a file system

Having used Xen and its pygrub for a while, I'm now trying to do something similar with KVM/qemu. Basically, I have a LVM logical volume (though that could as well be a file) that contains the root ...
7
votes
2answers
2k views

How to block loading kernel module only in single user boot when blacklist fails?

On a "Linux debian 2.6.32-5-amd64 #1 SMP" installation where loading a kernel module (mpt2sas) is desired to be delayed to be loaded after starting sshd and users can remotely login, the mpt2sas ...
7
votes
1answer
2k views

after BIOS splash, will not boot, asked to select OS, but can't

I'm running Linux Mint 13 MATE 64-bit. Everything has been working for several weeks. Yesterday, when I tried to boot up my computer, after the BIOS screen flashes I reach a screen with a black ...
7
votes
1answer
3k views

Fedora 17 Freezes on Boot

I have been having issues with Fedora 17 not booting after the latest round of updates. I am able to enter the pass for my disk encryption, the boot logo acts normally but after the animation is ...
7
votes
1answer
7k views

How do I add PC BSD / FreeBSD to Grub 2 boot loader?

I have Ubuntu 10.04 installed as my primary operating system, and I installed PC BSD in a different partition: /dev/sda4 without installing it's boot loader. I figured out that I need to edit ...
7
votes
1answer
8k views

rpcbind-“warning” on boot

On my debian testing system, I get these messages in my /var/log/boot file: Starting rpcbind daemon...rpcbind: Cannot open '/var/run/rpcbind/rpcbind.xdr' file for reading, errno 2 (No such file or ...
7
votes
2answers
552 views

Determine what program is in my MBR code

I've done a lot of partitioning / dual booting on my Macbook Pro. Right now I have Mac OS X installed along with Ubuntu 12.04, with Grub installed on the Ubuntu partition. I am wondering - what is ...
6
votes
5answers
899 views

Can you make a linux system halt and boot my Raspberry-pi at certain times?

How to make a system turn itself off and back on at different times. For example I would have my "server" turn off at 4 A.M then turn back on at 5 A.M every day. Is this possible? I am using a ...
6
votes
2answers
8k views

Why do iptables rules disappear when restarting my Debian system?

I add this rule: sudo iptables -t nat -A OUTPUT -d a.b.c.d -p tcp \ --dport 1723 -j DNAT --to-destination a.b.c.d:10000 When restart computer rules are deleted. Why? What I can do to make ...