Split dev-filesystem

Author: cirosantilli

README.md

@@ -30,7 +30,7 @@ Includes Linux concepts and utilities that work on Linux, not necessarily in the
     1. [dmesg](demesg.md)
     1. [installkernel](installkernel.md)
 1.  Initialization
-    1. [Install OS](install-os.md): how to install a new OS
+    1. [Install Operating System](install-operating-system.md): how to install a new OS
     1. [Boot](boot.md)
     1. [GRUB](grub.md)
     1. [Init](init.md): System V, Upstart
@@ -53,6 +53,7 @@ Includes Linux concepts and utilities that work on Linux, not necessarily in the
     1.  [mountall](mountall.md)
     1.  [pathchk](pathchk.md)
     1.  [swap partition](swap-partition.md)
+    1.  [tune2fs](tune2fs.md)
     1.  [UUID](uuid.md)
     1.  ext filesystems
         1. [e2label](e2label.md)
@@ -63,6 +64,8 @@ Includes Linux concepts and utilities that work on Linux, not necessarily in the
         1.  [proc filesystem](proc-filesystem.md)
         1.  [dev filesystem](dev-filesystem.md)
             1. [mknod](mknod.md)
+            1. [/dev/loop](/dev/loop.md)
+            1. [/dev/sr0](/dev/sr0.md)
         1.  [sysfs](sysfs.md)
         1.  [ramfs](ramfs.md)
         1.  [binfmt_misc filesystem](binfmt-misc-filesystem.md)
@@ -89,6 +92,9 @@ Includes Linux concepts and utilities that work on Linux, not necessarily in the
     1.  File managers
         1. [Krusader](krusader.md)
         1. [vifm](vifm.md)
+    1.  Partitions
+        1.  [parted](parted.md)
+        1.  [gparted](gparted.md)
     1.  [CD DVD](cd-dvd.md)
         [isoinfo](isoinfo.md)
         [eject](eject.md)

cloc.md

@@ -4,6 +4,10 @@ Count files, line of code, empty lines and comment lines under directory.
 
     cloc .
 
+Does not seem possible to add new languages. For more flexibility see: <http://stackoverflow.com/questions/1358540/how-to-count-all-the-lines-of-code-in-a-directory-recursively> A good one is:
+
+    ( find ./ -name '*.tex' -print0 | xargs -0 cat ) | wc -l
+
 Sample output for GDB:
 
         4770 text files.

dd.md

@@ -46,19 +46,19 @@ Default values: 512 B.
 
 ## count
 
-Copy up to count blocks (defined by bs):
+Copy up to count blocks (defined by `bs`):
 
-    [ `echo -n 1234 | dd status=none bs=2 count=1` = 12 ] || exit 1
-    [ `echo -n 1234 | dd status=none bs=1 count=3` = 123 ] || exit 1
+    [ "$(printf '1234' | dd status=none bs=2 count=1)" = '12' ] || exit 1
+    [ "$(printf '1234' | dd status=none bs=1 count=3)" = '123' ] || exit 1
 
 ## size suffixes
 
--`c`: 1 (char)
--`w`: 2 (word)
--`kB`: 1000
--`K`: 1024
--`MB`: 1000*1000
--`M`: 1024*1024
+- `c`: 1 (char)
+- `w`: 2 (word)
+- `kB`: 1000
+- `K`: 1024
+- `MB`: 1000*1000
+- `M`: 1024*1024
 
 and so on for G, T, P, E, Z and Y!
 
@@ -101,6 +101,12 @@ Most useful ones:
 
 TODO
 
+## verbose
+
+## Monitor progress
+
+Not easy: <http://askubuntu.com/questions/215505/how-do-you-monitor-the-progress-of-dd>
+
 ## Applications
 
 Copy one hard disk to another:
@@ -132,7 +138,7 @@ We recommend sticking to the GNU version, as it is maintained by an organization
 
 Basic usage:
 
-    dd -fv /dev/from /dev/to ddrescue.log
+    ddrescue -fv /dev/from /dev/to ddrescue.log
 
 - `-f`: write even if destination exists already. Required to copy device files to other device files.
 - `-v`: print the transfer status while it is going on.

dev-filesystem.md

@@ -1,12 +1,11 @@
 # dev filesystem
 
-Contains device driver files.
+Contains device driver files, and things related to device drivers like symlinks that give nice names to device drives.
 
-To really understand what is going on, learn how to make a minimal device driver yourself. This is not documented here.
+To understand what is going on, make a minimal device driver yourself. This is not documented here. Prerequisites you will learn when you do that:
 
-Standard device number and paths are documented at: <http://www.lanana.org/docs/device-list/devices-2.6+.txt>, which is part of the LSB.
-
-Some devices are created automatically by the Kernel even if there is no corresponding hardware to offer services under read write, e.g. random number generation.
+- what do the type, major and minor numbers mean
+- you can device arbitrary effects to standard file system calls like `open` and `close` on device files. They are usually not represented on disk in any way.
 
 ## devtmpfs
 
@@ -148,6 +147,18 @@ Discussion: <http://unix.stackexchange.com/questions/60641/linux-difference-betw
 
 Device files of this type represent block devices such as hard disks or flash memory.
 
+Type, major, minor: block, 8, X, one per partition:
+
+    brw-rw---- 1 root disk 8, 0 Aug 23 03:45 /dev/sda
+    brw-rw---- 1 root disk 8, 1 Aug 23 04:43 /dev/sda1
+    brw-rw---- 1 root disk 8, 2 Aug 23 03:45 /dev/sda2
+    brw-rw---- 1 root disk 8, 3 Aug 23 03:45 /dev/sda3
+    brw-rw---- 1 root disk 8, 4 Aug 23 03:45 /dev/sda4
+    brw-rw---- 1 root disk 8, 5 Aug 23 03:45 /dev/sda5
+    brw-rw---- 1 root disk 8, 6 Aug 23 03:45 /dev/sda6
+    brw-rw---- 1 root disk 8, 7 Aug 23 03:45 /dev/sda7
+    brw-rw---- 1 root disk 8, 8 Aug 23 03:45 /dev/sda8
+
 The first device is `sda`, the second `sdb`, and so on.
 
 Also, partitions inside those devices have device files for them too.
@@ -182,18 +193,42 @@ Now note that when you move the mouse, cat spits something out to the screen!
 
 `mice` is the combination of all mice, and each other `mouseX` is a single mouse device.
 
-## loop
+## /dev/shm
 
-## loop0
+Files created by `shm_open` calls. This function is part of POSIX, but creation of the files under `/dev` is not.
 
-## loop1
+## /dev/disk
 
-TODO
+Symlinks to partition identifiers.
 
-Type, major, minor: block, 7, `X` for `loopX`
+Allows you to get identifier info.
 
-Used to mount regular files that contain filesystems instead of device files as is usual.
+If id no present, link not there.
 
-## /dev/shm
+TODO what is the name of the subsystem that implements this? Where is it documented?
 
-Files created by `shm_open` calls. This function is part of POSIX, but creation of the files under `/dev` is not.
+Example:
+
+    ls -l /dev/disk/
+
+Sample output:
+
+    total 0
+    drwxr-xr-x 2 root root 420 Aug 23  2015 by-id
+    drwxr-xr-x 2 root root 100 Aug 23  2015 by-label
+    drwxr-xr-x 2 root root 180 Aug 23  2015 by-uuid
+
+Then:
+
+    ls -l /dev/disk/by-id/
+
+Sample output:
+
+    total 0
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 322246df-fed3-42f7-ba4d-4d72d6cce95f -> ../../sda5
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 5CE89967E8994066 -> ../../sda3
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 84f8087d-fc74-45b8-a6a2-180856b48982 -> ../../sda6
+    lrwxrwxrwx 1 root root 10 Aug 23 04:43 A6DA9BF3DA9BBE4D -> ../../sda1
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 D0EC9F59EC9F38A4 -> ../../sda2
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 e45497f8-6295-41da-ad8c-90dbbac264e8 -> ../../sda8
+    lrwxrwxrwx 1 root root 10 Aug 23 03:45 ff1b6e50-82ff-4696-823f-774b0f803298 -> ../../sda7

fdisk.md

@@ -2,12 +2,14 @@
 
 View and edit partition tables and disk parameters.
 
+Mnemonic: Format disk.
+
+util-linux package.
+
 REPL interface.
 
 Does not create filesystems. For that see: `mke2fs` for ext systems.
 
-Mnemonic: Format disk.
-
 Better use gparted for simple operations if you have X11
 
 To view/edit partitions with interactive CLI prompt interface.
@@ -37,6 +39,8 @@ Sample output for each disk:
     /dev/sda6    940277760  948099071   3910656  82 Linux swap / Solaris
     /dev/sda7    907640832  940267519  16313344  83 Linux
 
+TODO: what is the `boot` column?
+
 ## REPL
 
 Edit partitions for `sdb` on REPL interface:
@@ -48,9 +52,9 @@ Operation: make a list of changes to be made, then write them all to disk and ex
 Most useful commands:
 
 - `-m`: list options
-- `-p`: print info on partition, same as using `-l` option.
-- `-o`: create new DOS partition table.
-- `-n`: create new partition.
-- `-d`: delete a partition.
-- `-w`: write enqueued changes and exit.
+- `-p`: print info on partition, same as using `-l` option
+- `-o`: create new DOS partition table
+- `-n`: create new partition
+- `-d`: delete a partition
+- `-w`: write enqueued changes and exit
 

filesystem.md

@@ -119,10 +119,6 @@ The MBR can only be at the start of a physical partition, not of a logical parti
 
 This is why on bootloader configurations you give `/dev/sda`, instead of `/dev/sda1-4`.
 
-## fuseblk
-
-TODO. NTFS partitions as such.
-
 ## Format disks
 
 To format a disk is to prepare it for initial utilization, often destroying all data it contains.
@@ -188,47 +184,12 @@ You should only use on partition devices (ex: `sda1`), not on the entire devices
 
 If you want to edit the partition table, first use a tool like `fdisk`.
 
-## tune2fs
-
-Get and set parameters of ext filesystems that can be tuned after creation.
-
-List all parameters:
-
-    sudo tune2fs -l /dev/sda5
-
-## gparted
-
-GUI to `fdisk` + `mke2fs.`
-
-Very powerful and simple to use.
-
-## parted
-
-Get information on all partitions
-
-Very useful output form:
-
-    sudo parted -l
-
-Sample output:
-
-    Number Start  End   Size  Type   File system   Flags
-    1   1049kB 1574MB 1573MB primary  ntfs      boot
-    2   1574MB 102GB  100GB  primary  ntfs
-    4   102GB  485GB  384GB  extended
-    5   102GB  465GB  363GB  logical  ext4
-    7   465GB  481GB  16.7GB logical  ext4
-    6   481GB  485GB  4005MB logical  linux-swap(v1)
-    3   485GB  500GB  14.7GB primary  ntfs
-
 ## sda
 
 ## sdb
 
 ## hda
 
-## Device files
-
 Each hard disk and partition corresponds to device file.
 
 There are many types of device files. In particular, hard disks and partitions are block device files.
@@ -264,6 +225,10 @@ If a MBR is not present and a filesystem starts directly at the start of the dev
 
 ### IDE
 
+### PATA
+
+### Parallel ATA
+
 ### hd vs sd
 
 `hd` is for IDE disks, `sd` for SATA disks.
@@ -274,45 +239,18 @@ SATA stands for Serial Advanced Technology Attachment (or Serial ATA) and IDE is
 
 But by the beginning of 2007, SATA had largely replaced IDE in all new systems.
 
-<http://www.diffen.com/difference/IDE_vs_SATA>
-
-## Raw device
-
-<http://en.wikipedia.org/wiki/Raw_device>
-
-Bypasses the OSs filesystem management like caching, allowing user programs to do it
-
-## sr0
-
-CD DVD.
-
-`/dev/cdrom` is a symlink to it.
+Both have the same device number 8.
 
-## mmcblk0
-
-A SanDisk SD card had a device named `mmcblk0`.
-
-## /dev/disk
-
-Symlinks to partition identifiers.
-
-Allows you to get identifier info.
-
-If id no present, link not there.
+<http://www.diffen.com/difference/IDE_vs_SATA>
 
-Example:
+### SCSI
 
-    cd /dev/disk/
-    ls -l
-    by-id
-    by-label
-    by-path
-    by-uuid
+Both SATA and IDE are SCSI. This is why both `hd` and `sd` have the same major device number.
 
-    ls -l by-id
+<https://en.wikipedia.org/wiki/SCSI>
 
-## fsck
+## Raw device
 
-File System Check.
+<http://en.wikipedia.org/wiki/Raw_device>
 
-Check and repair Linux filesystems.
+Bypasses the OSs filesystem management like caching, allowing user programs to do it

getconf.md

@@ -0,0 +1,13 @@
+# getconf
+
+Get system configuration variables.
+
+TODO how are those obtained from the Linux kernel? Via `getrlimit`?
+
+Get all:
+
+    getconf -a
+
+Get one:
+
+    getconf MAX_ARG

gparted.md

@@ -0,0 +1,5 @@
+# gparted
+
+GUI to `fdisk` + `mke2fs.`
+
+Very powerful and simple to use.

gpu.md

@@ -69,3 +69,13 @@ For example, from the `lspci` output, in `GF108M [NVS 5400M]`:
 ### NVIDIA settings
 
 To check that the installation is working, use `nvidia-settings`, which monitors the GPU, and will show if the GPU is not properly installed.
+
+## dGPU
+
+Discrete GPU, a traditional GPU separate from the CPU, with it's own internal memory.
+
+## IGP
+
+Intermediate between CPU and GPU, uses RAM memory.
+
+<http://en.wikipedia.org/wiki/Graphics_processing_unit#Integrated_graphics_solutions>

grub.md

@@ -159,6 +159,14 @@ Recognizes Linux and Windows.
 
 TODO how to use it
 
+## Multiboot specification
+
+<https://en.wikipedia.org/wiki/Multiboot_Specification>
+
+Standard created by GRUB for booting OSes.
+
+Followed by Linux and many NIXes, but not Windows or Mac.
+
 ## Bibliography
 
 -   <http://www.dedoimedo.com/computers/grub-2.html>