COMP 3000 2011 Report: ttylinux - Revision history

Kmacmart: /* References */

2011-12-14T03:22:52Z

References

← Older revision		Revision as of 03:22, 14 December 2011
Line 142:		Line 142:

	==References==		==References==
	"ttylinux Homepage" Minimal Linux. Web. 19 Oct, 2011. <http://~~www~~.~~minimalinux.org/ttylinux/~~>		"ttylinux Homepage" Minimal Linux. Web. 19 Oct, 2011. <http://ttylinux.net>

	"ttylinux User Guide" Minimal Linux. Web. 18 Nov, 2011. <http://~~www~~.~~minimalinux.org/ttylinux~~/Documents/single/temp.html>		"ttylinux User Guide" Minimal Linux. Web. 18 Nov, 2011. <http://ttylinux.net/Documents/single/temp.html>

	"Dropbear SSH server and client" Matt Johnston. Web. 5 Dec, 2011. <https://matt.ucc.asn.au/dropbear/dropbear.html>		"Dropbear SSH server and client" Matt Johnston. Web. 5 Dec, 2011. <https://matt.ucc.asn.au/dropbear/dropbear.html>

Kmacmart: /* Usage Evaluation */

2011-12-14T03:22:12Z

Usage Evaluation

← Older revision		Revision as of 03:22, 14 December 2011
Line 47:		Line 47:

	==Usage Evaluation==		==Usage Evaluation==
	To see if ttylinux would really live up to its name, I ran the command "# du -c -m /" and was impressed to find that the full i686 install only took up ~25 megabytes. The ttylinux [[http://~~www~~.~~minimalinux.org/ttylinux/~~ project website]] reports on its front page that it "has an 8 MB file system and runs on i486 computers within 28 MB of RAM, but provides a complete command line environment and is ready for internet access", but digging a bit deeper I found that this is only true for the 'sm' version that uses a static '/dev' environment and uClib instead of Glibc, unlike the 'ut' version I installed, which the website states that it should have a 24 megabyte filesystem, just like the one I installed.		To see if ttylinux would really live up to its name, I ran the command "# du -c -m /" and was impressed to find that the full i686 install only took up ~25 megabytes. The ttylinux [[http://ttylinux.net project website]] reports on its front page that it "has an 8 MB file system and runs on i486 computers within 28 MB of RAM, but provides a complete command line environment and is ready for internet access", but digging a bit deeper I found that this is only true for the 'sm' version that uses a static '/dev' environment and uClib instead of Glibc, unlike the 'ut' version I installed, which the website states that it should have a 24 megabyte filesystem, just like the one I installed.

	Command line programs that are typically included in distributions of Linux like 'file', 'man' and 'tree', are left out of ttylinux to conserve space, and while it did take some getting used to initially, not having them in the end slowed me down at times, but it never prevented me from doing what I'd intended to. I was sad to find 'vi' in my $PATH instead of 'vim', which brings much more to the table than a tailing 'm', but in the same respect as the command line applications that weren't included, the decision to choose 'vi' instead is understandable if you consider how much more space 'vim' would have taken up. Taking a look at what ttylinux '''does''' include on the other hand, I discovered that it actually has a fairly respectable array of functionality packed in its ~25 megabytes. It uses Busybox to provide a basic structure and set of Unix utilities, then includes a carefully selected collection of programs like 'adduser', 'wget' and 'fuser', which all seem to perform a commonly required task that would either be difficult or impossible to do without. There are also [[http://~~www.minimalinux~~.~~org/ttylinux~~/addons.html add-ons]] available to provide support for ntfs, the calc utility and an http server, and a [[http://~~www.minimalinux~~.~~org/ttylinux~~/source.html source distribution]] exists that includes a build system if additional functionality is required.		Command line programs that are typically included in distributions of Linux like 'file', 'man' and 'tree', are left out of ttylinux to conserve space, and while it did take some getting used to initially, not having them in the end slowed me down at times, but it never prevented me from doing what I'd intended to. I was sad to find 'vi' in my $PATH instead of 'vim', which brings much more to the table than a tailing 'm', but in the same respect as the command line applications that weren't included, the decision to choose 'vi' instead is understandable if you consider how much more space 'vim' would have taken up. Taking a look at what ttylinux '''does''' include on the other hand, I discovered that it actually has a fairly respectable array of functionality packed in its ~25 megabytes. It uses Busybox to provide a basic structure and set of Unix utilities, then includes a carefully selected collection of programs like 'adduser', 'wget' and 'fuser', which all seem to perform a commonly required task that would either be difficult or impossible to do without. There are also [[http://ttylinux.net/addons.html add-ons]] available to provide support for ntfs, the calc utility and an http server, and a [[http://ttylinux.net/source.html source distribution]] exists that includes a build system if additional functionality is required.

	Being minimalist by design, ttylinux is a lean OS that does an excellent job at providing an up-to-date, functional distribution that still manages to be one of the smallest on the ''block''. I can't really fault it for what it doesn't include, and if anyone with a bit more space might want to use ttylinux as a basis to work from, the 'ws' variant available on the [[http://~~www~~.~~minimalinux.org/ttylinux~~/downloadPC.html downloads]] page includes Alsa and more importantly GCC, so new applications can be built. Thinking back on my experience with ttylinux, the only real critique I can make at this point is for including the package selection feature in the non-beta ttylinux-installer script when it's clearly not yet stable, but overall I really do feel like it does a good job of accomplishing what it set out to do, and that it does it well.		Being minimalist by design, ttylinux is a lean OS that does an excellent job at providing an up-to-date, functional distribution that still manages to be one of the smallest on the ''block''. I can't really fault it for what it doesn't include, and if anyone with a bit more space might want to use ttylinux as a basis to work from, the 'ws' variant available on the [[http://ttylinux.net/downloadPC.html downloads]] page includes Alsa and more importantly GCC, so new applications can be built. Thinking back on my experience with ttylinux, the only real critique I can make at this point is for including the package selection feature in the non-beta ttylinux-installer script when it's clearly not yet stable, but overall I really do feel like it does a good job of accomplishing what it set out to do, and that it does it well.

	=Part 2=		=Part 2=

Kmacmart: /* Installation */

2011-12-14T03:21:14Z

Installation

← Older revision		Revision as of 03:21, 14 December 2011
Line 11:		Line 11:
	To test this distribution, I used Oracle VM VirtualBox Version 4.1.0r73009 and created a new VM using the Linux 2.6 presets and 2 gigabytes of storage, I configured it to have 16 megabytes of video memory, 64 megabytes ram and a bridged Ethernet device to connect directly through my network's router. I then used the virtual media manager in VirtualBox to mount the ~35 megabyte ut-ttylinux-i686-12.6.iso, which is an image of the most recent version (12.6) of the smallest i686 variant 'ut', and booted the virtual machine.		To test this distribution, I used Oracle VM VirtualBox Version 4.1.0r73009 and created a new VM using the Linux 2.6 presets and 2 gigabytes of storage, I configured it to have 16 megabytes of video memory, 64 megabytes ram and a bridged Ethernet device to connect directly through my network's router. I then used the virtual media manager in VirtualBox to mount the ~35 megabyte ut-ttylinux-i686-12.6.iso, which is an image of the most recent version (12.6) of the smallest i686 variant 'ut', and booted the virtual machine.

	The ttylinux installer initially greeted me with some boot options that allowed a number of settings and services available during the installation to be tweaked, and not needing any of these things to be changed, I pressed ''enter'' to begin the installation. It loaded into a live ttylinux environment that wasn't too different from the final installed version, and it presented a shell prompt that I was able use to login as 'root' with the password 'password'. The decidedly out of date [[http://~~www~~.~~minimalinux.org/ttylinux~~/Documents/single/temp.html ttylinux User Guide]] explained a method of installation that appeared to be a somewhat manual process, but when I discovered a file named 'install.conf' in my user's home directory explaining a much more automated process, I decided to leave the ttylinux User Guide behind.		The ttylinux installer initially greeted me with some boot options that allowed a number of settings and services available during the installation to be tweaked, and not needing any of these things to be changed, I pressed ''enter'' to begin the installation. It loaded into a live ttylinux environment that wasn't too different from the final installed version, and it presented a shell prompt that I was able use to login as 'root' with the password 'password'. The decidedly out of date [[http://ttylinux.net/Documents/single/temp.html ttylinux User Guide]] explained a method of installation that appeared to be a somewhat manual process, but when I discovered a file named 'install.conf' in my user's home directory explaining a much more automated process, I decided to leave the ttylinux User Guide behind.

	To install ttylinux using 'install.conf', I needed to use fdisk to partition the VM's disk first, and I used a similar configuration to the one in the sample that the default 'install.conf' provides. I then used 'vi' to edit the 'fstab' section in 'install.conf' to reflect the the partitions I created, and to test ttylinux's claim of being up to date, I set the filesystems of everything (except for swap, of course) to ext4, resulting in the following configuration:		To install ttylinux using 'install.conf', I needed to use fdisk to partition the VM's disk first, and I used a similar configuration to the one in the sample that the default 'install.conf' provides. I then used 'vi' to edit the 'fstab' section in 'install.conf' to reflect the the partitions I created, and to test ttylinux's claim of being up to date, I set the filesystems of everything (except for swap, of course) to ext4, resulting in the following configuration:

Kmacmart: /* Background */

2011-12-14T03:20:37Z

Background

← Older revision		Revision as of 03:20, 14 December 2011
Line 3:		Line 3:
	The distribution I chose to discuss is called '''ttylinux''', and its named after its initial orientation towards ''TeleTYpewriter'' (or TTY serial) interfaces. It caters to an audience of users looking to get older hardware running on the web or lightweight systems they can boot from USB, and to developers who are looking for an OS they can base their own variant of Linux on, including possibly one modified to run on embedded systems. It was initially developed in 2001 by ''Pascal Schmidt'', who focused on getting it running on serial interfaces over networks, but when ''Douglas Jerome'' took his place in 2008, the focus of the project moved away from connecting to serial interfaces and towards its intended purpose of being "one of the smallest up-to-date Linux systems that is similar to a larger distribution", as stated on the website.		The distribution I chose to discuss is called '''ttylinux''', and its named after its initial orientation towards ''TeleTYpewriter'' (or TTY serial) interfaces. It caters to an audience of users looking to get older hardware running on the web or lightweight systems they can boot from USB, and to developers who are looking for an OS they can base their own variant of Linux on, including possibly one modified to run on embedded systems. It was initially developed in 2001 by ''Pascal Schmidt'', who focused on getting it running on serial interfaces over networks, but when ''Douglas Jerome'' took his place in 2008, the focus of the project moved away from connecting to serial interfaces and towards its intended purpose of being "one of the smallest up-to-date Linux systems that is similar to a larger distribution", as stated on the website.

	You can download ttylinux from the [[http://~~www~~.~~minimalinux.org/ttylinux~~/ project website]] or one of a number of the mirrors listed there. Derived from scratch, the smallest variant of ttylinux called 'em' has a mere ~8 megabyte filesystem, and it only takes up ~12 megabytes including the kernel. That said, the smallest variant available for i686 called 'ut' uses ~25 megabytes, and this is what I've used to test with for this report.		You can download ttylinux from the [[http://ttylinux.net/ project website]] or one of a number of the mirrors listed there. Derived from scratch, the smallest variant of ttylinux called 'em' has a mere ~8 megabyte filesystem, and it only takes up ~12 megabytes including the kernel. That said, the smallest variant available for i686 called 'ut' uses ~25 megabytes, and this is what I've used to test with for this report.

	==Installation/Startup==		==Installation/Startup==

Kmacmart: /* References */

2011-12-06T09:54:52Z

References

← Older revision		Revision as of 09:54, 6 December 2011
Line 185:		Line 185:

	"Bash" GNU Project. Web. 5 Dec, 2011. <http://www.gnu.org/software/bash/bash.html>		"Bash" GNU Project. Web. 5 Dec, 2011. <http://www.gnu.org/software/bash/bash.html>

			"proc(5) - Linux man page" die.net. Web. 5 Dec, 2011. <http://linux.die.net/man/5/proc>

	Linux man pages: <man init>		Linux man pages: <man init>

Kmacmart: /* Initialization */

2011-12-06T09:48:34Z

Initialization

← Older revision		Revision as of 09:48, 6 December 2011
Line 139:		Line 139:
	The next part of '/etc/rc.d/rc.sysinit' loads a collection of optional features such as networking support, whether logins are allowed etc, and these use the values in the local variables defined earlier using '/proc/cmdline'. It then executes a hack to prevent ssh from generating keys if the cpu is too slow, and includes '/etc/rc.d/rc.local' to run any user-supplied scripts it might include. Any system services placed in '/etc/rc.d/rc.startup/' (context, crond, firewall, gpm, inetd, network, random, rnd-pwd, sshd, syslog) will now load, and what follows is a series of checks to see what state the computer is in (first boot?), so it can provide the appropriate clean-up and/or fixes required before finally returning to '/etc/inittab' to finish initializing the system.		The next part of '/etc/rc.d/rc.sysinit' loads a collection of optional features such as networking support, whether logins are allowed etc, and these use the values in the local variables defined earlier using '/proc/cmdline'. It then executes a hack to prevent ssh from generating keys if the cpu is too slow, and includes '/etc/rc.d/rc.local' to run any user-supplied scripts it might include. Any system services placed in '/etc/rc.d/rc.startup/' (context, crond, firewall, gpm, inetd, network, random, rnd-pwd, sshd, syslog) will now load, and what follows is a series of checks to see what state the computer is in (first boot?), so it can provide the appropriate clean-up and/or fixes required before finally returning to '/etc/inittab' to finish initializing the system.

	Six tty consoles are now loaded thanks to '/etc/inittab', which then sets the key combination ctrl-alt-del to launch '/sbin/reboot', and the shutdown script '/etc/rc.d/rc.sysdone' to run as the computer shuts itself down. The greeting above the login prompt is generated from the file '/etc/issue', and the the login prompt below it allows you to login and finally use the system!		Six tty consoles are now loaded thanks to '/etc/inittab', which then sets the key combination ctrl-alt-del to launch '/sbin/reboot' and the shutdown script '/etc/rc.d/rc.sysdone' to run as the computer shuts itself down. The greeting above the login prompt is generated from the file '/etc/issue', and the the login prompt below it allows you to login and finally use the system!

	==References==		==References==

Kmacmart: /* Initialization */

2011-12-06T09:41:21Z

Initialization

← Older revision		Revision as of 09:41, 6 December 2011
Line 137:		Line 137:
	Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.		Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.

	The next part of '/etc/rc.d/rc.sysinit' loads a collection of optional features such as networking support, and the ~~resulting configuration is defined by those~~ variables defined earlier using '/proc/cmdline'. It then executes a hack to prevent ssh from generating keys if the cpu is too slow, and includes '/etc/rc.d/rc.local' to run any user-supplied scripts. Any system services ~~that are set to start at boot by being~~ placed in '/etc/rc.d/rc.startup/' (context, crond, firewall, gpm, inetd, network, random, rnd-pwd, sshd, syslog) ~~are then loaded before the script runs through~~ a series of checks ~~for things like whether it's~~ the ~~PC's~~ first boot, and ~~then cleans~~/fixes ~~things up where appropriate~~ before finally returning to '/etc/inittab' to finish initializing the system.		The next part of '/etc/rc.d/rc.sysinit' loads a collection of optional features such as networking support, whether logins are allowed etc, and these use the values in the local variables defined earlier using '/proc/cmdline'. It then executes a hack to prevent ssh from generating keys if the cpu is too slow, and includes '/etc/rc.d/rc.local' to run any user-supplied scripts it might include. Any system services placed in '/etc/rc.d/rc.startup/' (context, crond, firewall, gpm, inetd, network, random, rnd-pwd, sshd, syslog) will now load, and what follows is a series of checks to see what state the computer is in (first boot?), so it can provide the appropriate clean-up and/or fixes required before finally returning to '/etc/inittab' to finish initializing the system.

	Six tty consoles are now loaded thanks to '/etc/inittab', which then sets the key combination ctrl-alt-del to launch '/sbin/reboot', and the shutdown script '/etc/rc.d/rc.sysdone' to run as the computer shuts itself down. The greeting above the login prompt is generated from the file '/etc/issue', and the the login prompt below allows you to login and finally use ~~your~~ system!		Six tty consoles are now loaded thanks to '/etc/inittab', which then sets the key combination ctrl-alt-del to launch '/sbin/reboot', and the shutdown script '/etc/rc.d/rc.sysdone' to run as the computer shuts itself down. The greeting above the login prompt is generated from the file '/etc/issue', and the the login prompt below it allows you to login and finally use the system!

	==References==		==References==

Kmacmart: /* Initialization */

2011-12-06T09:09:22Z

Initialization

← Older revision		Revision as of 09:09, 6 December 2011
Line 133:		Line 133:
	The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.		The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.

	Next, '/etc/rc.d/rc.sysinit' defines a number of local variables with empty default values, and it uses '/proc/cmdline' to give them the value supplied as a command line argument if one was given. ~~Checking~~ to see if the kernel was passed a hostname, ~~then updating~~ '/etc/HOSTNAME' and '/etc/hosts' if it was~~, $HOSTNAME is~~ then ~~set to the value in~~ '/etc/HOSTNAME' or 'localhost' if it'~~s empty, and the hostname is then set to this value after the ttylinux startup banner is configured to show~~. The kernel parameters ~~provided~~ by '/~~etc~~/sysctl~~.conf~~' ~~are then set~~ by '/~~sbin~~/sysctl', and the kernel log level is ~~set. Kernel~~ modules that haven't already been loaded ~~for reasons such as needing specific hardware that requires a module to be involved in the boot process, and which aren't loaded automatically as needed~~ by udev~~, will then be~~ loaded ~~using~~ the list of modules defined in /etc/modtab.		Next, '/etc/rc.d/rc.sysinit' defines a number of local variables with empty default values, and it uses '/proc/cmdline' to give them the value supplied as a command line argument if one was given. The script checks to see if the kernel was passed a hostname, and updates both '/etc/HOSTNAME' and '/etc/hosts' if it was. It then uses '/etc/HOSTNAME' to provide a value for $HOSTNAME if it contains one, or exports $HOSTNAME='localhost' if it doesn't. The kernel parameters are then set by '/sbin/sysctl' using the values provided by '/etc/sysctl.conf', and the kernel log level is then defined before any modules that haven't already been loaded by udev or the init script are now loaded from the list of modules defined in '/etc/modtab'.

	Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.		Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.

Kmacmart: /* Initialization */

2011-12-06T08:52:50Z

Initialization

← Older revision		Revision as of 08:52, 6 December 2011
Line 133:		Line 133:
	The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.		The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.

	Next, '/etc/rc.d/rc.sysinit' ~~sets default values for~~ a number of local variables ~~before assigning the ones specified in~~ '/proc/cmdline' ~~their~~ given ~~values, which will be used later on in the script~~. Checking to see if the kernel was passed a hostname, then updating '/etc/HOSTNAME' and '/etc/hosts' if it was, $HOSTNAME is then set to the value in '/etc/HOSTNAME' or 'localhost' if it's empty, and the hostname is then set to this value after the ttylinux startup banner is configured to show. The kernel parameters provided by '/etc/sysctl.conf' are then set by '/sbin/sysctl', and the kernel log level is set. Kernel modules that haven't already been loaded for reasons such as needing specific hardware that requires a module to be involved in the boot process, and which aren't loaded automatically as needed by udev, will then be loaded using the list of modules defined in /etc/modtab.		Next, '/etc/rc.d/rc.sysinit' defines a number of local variables with empty default values, and it uses '/proc/cmdline' to give them the value supplied as a command line argument if one was given. Checking to see if the kernel was passed a hostname, then updating '/etc/HOSTNAME' and '/etc/hosts' if it was, $HOSTNAME is then set to the value in '/etc/HOSTNAME' or 'localhost' if it's empty, and the hostname is then set to this value after the ttylinux startup banner is configured to show. The kernel parameters provided by '/etc/sysctl.conf' are then set by '/sbin/sysctl', and the kernel log level is set. Kernel modules that haven't already been loaded for reasons such as needing specific hardware that requires a module to be involved in the boot process, and which aren't loaded automatically as needed by udev, will then be loaded using the list of modules defined in /etc/modtab.

	Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.		Udev is then started by '/etc/rc.d/rc.sysinit', and '/dev', 'tmpfs' and '/dev/root' are all initialized before the script enables some low level features such as swapping, and the clock's time-zone is configured using '/etc/sysconfig/clock'. The root filesystem is remounted read-only before the script runs 'fsck' to check/fix any errors, and it's then remounted again back to read-write. The script attempts to mount a filesystem on /tmp, and then uses 'fsck' to check/fix the other filesystems before finally mounting them as well. With '/usr' available now, the script then exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and initializes console fonts and keyboard interactivity before attempting to load any scsi drives that may exist too and tidying up temporary files left behind. Now that the system is almost finished starting, the script attempts to load any module dependencies that might still be required by running 'depmod.

Kmacmart: /* Initialization */

2011-12-06T08:37:49Z

Initialization

← Older revision		Revision as of 08:37, 6 December 2011
Line 131:		Line 131:
	Most GNU/Linux environments (including ttylinux) execute a program called 'init' when they begin to load, and this program uses the configuration in a file called 'inittab' to then load the system. I took a look through ttylinux's rather brief '/etc/inittab', and found that it invokes '/etc/rc.d/rc.sysinit' almost immediately.		Most GNU/Linux environments (including ttylinux) execute a program called 'init' when they begin to load, and this program uses the configuration in a file called 'inittab' to then load the system. I took a look through ttylinux's rather brief '/etc/inittab', and found that it invokes '/etc/rc.d/rc.sysinit' almost immediately.

	The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports ~~the~~ $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.		The script in '/etc/rc.d/rc.sysinit' begins by configuring the the shell to avoid closing when it receives a keyboard interrupt, a non-zero exit status, or the use of unset variables. It then includes '/etc/rc.d/rc.functions', which exports $PATH='/bin:/sbin:/usr/bin:/usr/sbin' and the values of a number of other environment variables too before defining a collection of functions that get used later on. When '/etc/rc.d/rc.functions' returns, '/etc/rc.d/rc.sysinit' exports $PATH='/bin:/sbin' before proceeding to set the console loglevel to 1, mounting the pseudo file-systems 'sys', 'proc' and '/proc/bus/usb', and finally remounting the Root filesystem as read-write before setting up '/etc/mtab' so the boot process can really start.

	Next, '/etc/rc.d/rc.sysinit' sets default values for a number of local variables before assigning the ones specified in '/proc/cmdline' their given values, which will be used later on in the script. Checking to see if the kernel was passed a hostname, then updating '/etc/HOSTNAME' and '/etc/hosts' if it was, $HOSTNAME is then set to the value in '/etc/HOSTNAME' or 'localhost' if it's empty, and the hostname is then set to this value after the ttylinux startup banner is configured to show. The kernel parameters provided by '/etc/sysctl.conf' are then set by '/sbin/sysctl', and the kernel log level is set. Kernel modules that haven't already been loaded for reasons such as needing specific hardware that requires a module to be involved in the boot process, and which aren't loaded automatically as needed by udev, will then be loaded using the list of modules defined in /etc/modtab.		Next, '/etc/rc.d/rc.sysinit' sets default values for a number of local variables before assigning the ones specified in '/proc/cmdline' their given values, which will be used later on in the script. Checking to see if the kernel was passed a hostname, then updating '/etc/HOSTNAME' and '/etc/hosts' if it was, $HOSTNAME is then set to the value in '/etc/HOSTNAME' or 'localhost' if it's empty, and the hostname is then set to this value after the ttylinux startup banner is configured to show. The kernel parameters provided by '/etc/sysctl.conf' are then set by '/sbin/sysctl', and the kernel log level is set. Kernel modules that haven't already been loaded for reasons such as needing specific hardware that requires a module to be involved in the boot process, and which aren't loaded automatically as needed by udev, will then be loaded using the list of modules defined in /etc/modtab.