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dcore:core_concepts_explained [2015/05/04 13:39] – [dCore specifics] sm8psdcore:core_concepts_explained [2024/07/17 04:51] (current) – Link correction - dCore welcome page bernhard
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-====== dCore Concepts explained ======+====== dCore Concepts ======
  
-dCore, like TinyCore, uses standard technologies common to all Linux distributions in an ingenious way. A layman's understanding of these concepts helps understand the necessary steps for setting-up and managing a dCore installation.+dCore, like Tiny Core, uses standard technologies common to all Linux distributions in an ingenious way. A layman's understanding of these concepts helps understand the necessary steps for setting-up and managing a dCore installation. This simplified explanation cuts some technical corners and is meant to outline Tiny Core Linux to new users.
  
-===== Operating principles of Core-Linux ===== +===== Linux Operating System  ===== 
-The following presentation is extremely simplified and cuts some technical corners. It is meant to point out the technologies used by Core-Linux to new-comers. +To operate a modern computer, one needs an [[https://en.wikipedia.org/wiki/Operating_system|operating system]],in our case [[https://en.wikipedia.org/wiki/Linux|Linux]]. More precisely, we use the Linux [[http://en.wikipedia.org/wiki/Kernel_%28operating_system%29|kernel]] but that is not all it takes. The kernel operates your computer, that is it manages the hardware components including RAM, video, network, input devices like keyboard or mouse, hard-disks, USB- and other interfaces etc. Furthermore, it keeps an eye on files, users and permissions (and of course does a lot more work, too). 
- +
-==== Linux operating system  ==== +
-To operate a modern computer, one needs an operating system, [[http://en.wikipedia.org/wiki/Linux_kernel|Linux]] in our case. More precisely, we use the Linux [[http://en.wikipedia.org/wiki/Kernel_%28operating_system%29|kernel]] but that is not all it takes. The kernel operates your computer, that is it manages the hardware components including RAM, video, network, input devices like keyboard or mouse, hard-disks, USB- and other interfaces etc. Furthermore, it keeps an eye on files, users and permissions (and of course does a lot more work, too). +
  
 Simply put, the kernel is the first program running on a computer (neglecting BIOS/EFI and boot-loader). It does not do much on its own; instead it provides a platform for running user space programs. After the initial boot phase which makes the kernel run, control usually is handed over to the so-called [[http://en.wikipedia.org/wiki/Init|init-process]] ('/sbin/init') which calls the individual init-scripts. Simply put, the kernel is the first program running on a computer (neglecting BIOS/EFI and boot-loader). It does not do much on its own; instead it provides a platform for running user space programs. After the initial boot phase which makes the kernel run, control usually is handed over to the so-called [[http://en.wikipedia.org/wiki/Init|init-process]] ('/sbin/init') which calls the individual init-scripts.
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 Due to its very frugal nature, dCore makes use of [[http://en.wikipedia.org/wiki/BusyBox|BusyBox]] to provide shell and system tools. The shell provided by BusyBox is [[http://en.wikipedia.org/wiki/Almquist_shell|Ash]] (Almquist shell). It is "virtually" POSIX-compatible does not provide all the extras of other shells like Bash or Dash. Due to its very frugal nature, dCore makes use of [[http://en.wikipedia.org/wiki/BusyBox|BusyBox]] to provide shell and system tools. The shell provided by BusyBox is [[http://en.wikipedia.org/wiki/Almquist_shell|Ash]] (Almquist shell). It is "virtually" POSIX-compatible does not provide all the extras of other shells like Bash or Dash.
  
-==== dCore specifics ====+**[[http://wiki.tinycorelinux.net/dcore:welcome|> Return to the dCore Wiki Welcome page]]** 
 +===== dCore Specifics =====
 Running from RAM yields some interesting consequences which mostly revolve about the fact that the root file system used is not only minimal but also ephemeral in the sense that any change to it will be only written to RAM but not back to the initrd archive on disk. Running from RAM yields some interesting consequences which mostly revolve about the fact that the root file system used is not only minimal but also ephemeral in the sense that any change to it will be only written to RAM but not back to the initrd archive on disk.
  
 === Running from arbitrary file systems === === Running from arbitrary file systems ===
-dCore needs two files to run, namely the Linux kernel and the initrd. Both files can be loaded from arbitrary file systems, most notably FAT32 commonly used on USB-sticks. The file systems does not need to support the [[http://en.wikipedia.org/wiki/File_system_permissions|Linux file system permissions]].+dCore needs two files to run, namely the Linux kernel and the initrd. Both files can be loaded from arbitrary file systems, most notably FAT32 commonly used on USB-sticks. The file systems does not need to support the Linux file system [[http://en.wikipedia.org/wiki/File_system_permissions|permissions]].
  
 === Pristine image === === Pristine image ===
 At every boot the root system is in its pristine initial state. So there is no way of inadvertently breaking the system by mis-configuring any system files (but cf. [[#Persistence|below]]). At every boot the root system is in its pristine initial state. So there is no way of inadvertently breaking the system by mis-configuring any system files (but cf. [[#Persistence|below]]).
  
 +Picture yourself, or somebody else for that matter, issueing the command ''sudo mv ./* ~/data/'' but //omitting the tiny dot// by a lapse of concentration.
 +Sure enough, you will get an interesting collection of data in that folder, there will be error messages about Linux' fundamental inability of moving '/proc/', '/sys/' and maybe some more and, to round off the whole [[http://en.wikipedia.org/wiki/Snafu|snafu]], no further command will succeed and you won't even be recognized as valid system user any more. 
 +
 +Time to re-install from scratch on any regular operating system, probably.
 +With dCore you simply shut off the system ([[http://en.wikipedia.org/wiki/Magic_SysRq_key|magic SysRq]] should still work, although your keyboard layout might be messed up as well) and re-boot. Nothing more is left to do other than cleaning out your home directory.
 + 
 === Need for boot parameters === === Need for boot parameters ===
 As the root file system is loaded from the initrd there is no other way to influence early startup options than to specify them as boot parameters (e.g. black-listing kernel modules). As the root file system is loaded from the initrd there is no other way to influence early startup options than to specify them as boot parameters (e.g. black-listing kernel modules).
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 The '/home' and '/opt' directories can be included in the persistent storage or also put somewhere on a regular file system to make it persistent. The latter avoids (de-)compressing the full home folder at every bootup or shutdown. The '/home' and '/opt' directories can be included in the persistent storage or also put somewhere on a regular file system to make it persistent. The latter avoids (de-)compressing the full home folder at every bootup or shutdown.
  
 +**[[https://wiki.tinycorelinux.net/doku.php?id=dcore:welcome|> Return to the dCore Wiki Welcome page]]**
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