General :: Boot Up Process- The Read Only Rootfs Into VFS?
Mar 15, 2011
I've been reading various tutorials of the boot process but still am not clear. I don't care about grub stage 1 and 1.5 at the starting point of when the root filesystem is loaded into VFS(Virtualfilesystem), who is loading it, and from that point on. 1) Does grub load the root filesystem(read only) into VFS?2) Does the kernel load the root filesystem(read only) into VFS?3) Does INIT load the root filesystem(read only) into VFS?after this is concluded....Does INIT or the Kernel create the real root filesystem(rw)...right before the pivot.root
First post from a very new Linux user....I am trying to create a BASH script that will allow user to provide multiple directory names, Checks if the directory exists and if not create the directory.
I am using the following code:
Which works fine as long as the user enters a single directory name. How can I modify this so it will process all directory names user enters on the read response?
When I add the line (sleep 5 ) & in the script then the "while read" loop does not read all lines from the file, but only prints the first line.But when I remove the ( sleep 5 ) & from the script, then the script prints all lines as defined in the file.And how to solve the problem? I want to create a new process (for which the sleep is just an example) in the while loop:
Ive tried to install ubuntu via wubi. When it boots and i select ubuntu it starts the final installation tasks. But halts with no rootfs defined and says i need to define one. However it wont continue to boot obviously so am unable to do so. My PC does have raid but its switched off in the bios. I know dual booting is one way to go but would prefer initially to have it in the file. I can boot into the demo version and there is an install option there but doesnt offer my boot disk.
is there any tool can show the thread/process schedule information? i would like to know when the thread/process wakeup, and when it was suspend? it includes kernel and user space. With this information, i can know the thread/process task schedule, and calculate the MIPs.Another, do you know whether LTT support User space thread trace?
I have OpenSUSE 11.2. I removed bootchart and forgot to run mkinitrd. Now, right at the start of the boot process, I get boot/93-bootchart.sh: line 17: 462 Terminated stopinitrd 5
I Can't find any 93-bootchart.sh anywhere. Earlier I got an error message about non existing /sbin/bootchartd, but I just copied /bin/cat to /sbin/bootchartd using a GParted boot disk. I tried to use chroot with an OpenSUSE boot disk, but mkinitrd can't find the root device, which is there actually (/dev/sda5). How can I make my system boot again? now I managed to re-install the bootchart rpm, using OpenSUSE boot disk and chmod. The system starts again. But that annoying bootchart is still there. I will not try again to remove it. First I will try to figure out, how to disable it during the boot process.
I'm using CentOS 5.3. After booting up, where can I find the log file that contains if all services where successfully loaded or not? For example when computer boots you get a list of start services and they can be OK or FAILED. Is there a log file where this information is kept? I had a look in the following directory /var/log/ but not sure which one will contain the informaiton that I need.
I'm trying to upgrad from kernel 2.6.32.9 to 2.6.34.3 and I'm having problems.The boot finished with that old gem "Kernel panic - not syncing: Attempting to kill init !"I suspect that it's something to do with my PATA IDE driver because there have been kernel changes in this area.My problem is all the boot messages scroll off the top of the screen before I can read them and it's no use saying look at dmesg or /var/log/messages because the root fs isn't there - another reason why I think it's to do with the drivers.So my question is, is there some way I can slow down the boot process so that I have a chance of reading the messages ?
I have 2 Dell Inspirons 2200, I've installed F14 on in the past. Both laptops fail to initialize, I've verified media, and I'm able to boot the DVD on another system. The install fails at: Trying to unpack rootfs image as initramfs...
I have just installed the centos 5.3 on my server machine. It looks for a USB media to boot. But I am not able to figure it out what i have done wrong. Why does it asks for USB media?If I have created a dependency of USB to boot, Is there any way i can remove this dependency. Or I have to reinstall the OS again?
I got home today to find that my KDE login screen would not let me log in. It said the authentication process failed or something and I needed to terminate the screen lock process manually. So I go over to another virtual terminal and try to log in. As soon as I enter my user name, a bunch of errors come up and I am unable to log in. "This can't be good" I think to myself, and reboot.
I am greeted by this error upon booting: The error says that it says it cannot find /sbin/init. I loaded up a Ubuntu live CD and verified that /sbin/init is indeed present and all my other files still seem to be there. I tried booting into arch fallback on grub but that didn't work either. Midway through the day I SSHed my desktop from my phone and started it doing an upgrade. I was able to login.
For the past few days I was putting effort on understanding the software control flow starting from "Boot loader" to "Linux User space".
I am consolidating the entire process and putting forth in this forum...It would be great if someone can validate this..It might be useful to other new bees too.
Step 1 : Power up the board
Step 2 : The CPU control goes to EEPROM/storage memory where BIOS resides
Step 3: BIOS gets loaded in RAM and gets executed
Step 4: During execution, the selection of Boot device has to be done with the help of BIOS Menu [Blue screen appearance during start up in normal PC's]
Step 5: BIOS shall access the Bootloader stored in boot device [for eg.,Hard disk]. Boot loader is stored in MBR area.
for explanation purpose I take the following configurations
Bootloader = GRUB Boot Device = Hard Disk
Step 6: GRUB shall be loaded in RAM and gets executed
Step 7: GRUB shall load the KERNEL image to RAM. Kernel image is stored in Hard Disk.
The question of "How the GRUB knows where the Kernel image is stored".
The answer is 1. In the "Grub.config" file, the location of "Kernel Image" and " Ramdisk Image" [which will be discussed later in the section] is being given.
Step 8: Kernel Image followed by Ramdisk Image is loaded in RAM by GRUB bootloader
Step 9: Kernel Image gets executed...During execution, top portion of the code shall make initial hardware initialization and latter part of the code shall just decompress the Kernel Image
Step 10 : After decompressing the Kernel Image, it shall decompress the already loaded Ramdisk Image
Ram disk is just creating a temporary hard disk in RAM. The main responsibility includes it consists of minimal driver files, executables, directory structures to created a TEMPORARY ROOT FILE SYSTEM.
This Temporary Root File system shall be used by Kernel Image
1. Execute the executables to access the Hard disk 2. For creating Permanent Root File System in HARD DISK
Step 11 : Kernel Shall look for the file /Linuxrc in Ramdisk. Linuxrc is a USER script file [not sure]
Step 12: At the end of script file Linuxrc, the Ramdisk shall give the control to "USER SPACE" [path for writing the script not known]in Linux kernel
I am using Gentoo Linux and for a while now, the root file system is mounted read-only on booting. For obvious reasons, this is quite annoying as most services do not start up correctly (I do not use a separate file system for /var). After the system is up, I have to log in, remount the root file system read-write, fix /etc/mtab, mount all other file systems in from /etc/fstab and then start up all the missing daemons. I know that there are ways to make a system run properly with a read-only file system, but I would rather restore the old behaviour of a writable root file system.
The strange thing is that after running mount / -o remount,rw, the file system is mounted in writable mode without any errors. I suspected some problem with fsck, but now I have disabled automatic file system checks on the partition (tune2fs -c0 -i0).When I run dmesg, only these lines mention the partition at all, although I am not sure if not something gets lost because /var/log is not writable:
EXT3-fs (sda5): mounted filesystem with writeback data mode</code> EXT3-fs (sda5): using internal journal The line in /etc/fstab looks like this:
I have a high priority service that I start with sudo nice -n -10 process. This process does not need superuser rights though, except for the priority elevation. But nice requires superuser privileges to elevate priority.
Description of what the code does or what i intended to do:
1. Created a child process from parent process using 'fork()'
2. Sent a signal 'SIGALRM' from child process to parent process using 'sigqueue' function.
(The Third parameter of 'siqueue' function contains the message (message msg) which the child process wants to send to the parent process.'msg' is a stucture instance containing a) pid of child and b) string) 5. Print the 'msg' sent by child process inside the signal handler function 'sig_action_function' of the parent process I am getting some junk value when this line is executed
Code:
printf("%d ",msg->cpid);
I expected to get the pid of child process, which the child process sent to parent process through the signal.
as we all know Process Scheduler does Process scheduling and its a process as well. I was just wondering that if this happens then the Process "Process Scheduler" should be a part of Process queue as well.
So if there are 5 process are there in Process queue & process scheduler is administrating them then since its also a process, once it puts a process under RUN state it should itself go inside queue because at one instant only one process can get executed on a processor. This is quite confusing for me. Please help me out. I tried to search on this but could not find any relevant topics.
I have a process running on Linux.When i do ps -eaf | grep <myProcess>, it show muliple entries for <myProcess> with different pids for each entry.Kindly tell me what could be the reason for a process having multiple pids?
I want my samba to keep my windows attributes exactly what the user setted in windows I mean if it has read only file in win box and copy it to samba share ,samba keep it read only and same for other attributes but it does not do it now with my configuration:Quote:
[global] workgroup = DOMAIN server string = File Server
I've had a hell of a time with an extremely unpredictable recently built computer. I don't even know where to start with thetory, so I'll try to share some key facts.Running Fc12It is a Gigabyte GA-EP45T-UD3LR. Reviews on NewEgg havee complaints about instability and it's lack of claimed DDR3 support. I had to use setting described by another reviewer to underclock my memory to get it to work. It has since passed memtest many times.I've encountered mutliple occasions of a complete system freeze.
Booting after freeze seems to require a random amount of restarts to get it to come up. Sometimes I have to hit the reset button 30+ times until I can get the log in prompt to come up.Right now, I have one SATA HDD, in IDE compatibility mode in the system. dropped the FC12 Stable dvd in, the very DVD I installed the current system with, to install it again on another partition. I get to the same point every time, where it hangs:"trying to unpack rootfs image as initramfs"Googling that didn't help me much, since it mostly seemed to address people messing with their own kernel builds.
If I choose "boot from local drive" on the options list from the install DVD, it goes to "PRESS ANY KEY TO REBOOT" with a blinking underscore cursor. Where when I boot normally, it will either give me JUST the blinking underscore alone, or the FC loading screen with no progress. I suspect this motherboard is a pile of **** and needs to be RMA'ed, or simply returned. Anyone care to support or reject that hypothesis?
I've been running my shellscript for about half an hour now. It's taking longer than I thought to process all the data. I have the process ID of it. Is it possible to save the process and log out then log in and continue the process? I know how to pause a process using kill -pause pID and continue it using kill -cont pID. But that only work if you don't log out after pausing it.
