|
56 | 56 | and hand control over to a boot loader stored on a |
57 | 57 | persistent storage device. This boot loader will then |
58 | 58 | invoke an OS kernel from disk (or the network). In the |
59 | | - Linux case this kernel (optionally) extracts and |
60 | | - executes an initial RAM disk image (initrd) such as |
61 | | - <citerefentry><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| 59 | + Linux case, this kernel (optionally) extracts and |
| 60 | + executes an initial RAM disk image (initrd), such as |
| 61 | + generated by |
| 62 | + <citerefentry><refentrytitle>dracut</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
62 | 63 | which looks for the root file system (possibly using |
63 | 64 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
64 | 65 | for this). After the root file system is found and |
65 | | - mounted the initrd hands over control to the host's |
| 66 | + mounted, the initrd hands over control to the host's |
66 | 67 | system manager (such as |
67 | 68 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>) |
68 | | - stored on the OS image which is then responsible for |
| 69 | + stored on the OS image, which is then responsible for |
69 | 70 | probing all remaining hardware, mounting all necessary |
70 | 71 | file systems and spawning all configured |
71 | 72 | services.</para> |
72 | 73 |
|
73 | | - <para>On shutdown the system manager stops all |
| 74 | + <para>On shutdown, the system manager stops all |
74 | 75 | services, unmounts all file systems (detaching the |
75 | 76 | storage technologies backing them), and then |
76 | 77 | (optionally) jumps back into the initrd code which |
77 | 78 | unmounts/detaches the root file system and the storage |
78 | | - it resides on. As last step the system is powered down.</para> |
| 79 | + it resides on. As a last step, the system is powered down.</para> |
79 | 80 |
|
80 | 81 | <para>Additional information about the system boot |
81 | 82 | process may be found in |
|
90 | 91 | systems, services and drivers that are necessary for |
91 | 92 | operation of the system. On |
92 | 93 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
93 | | - systems this process is split up in various discrete |
| 94 | + systems, this process is split up in various discrete |
94 | 95 | steps which are exposed as target units. (See |
95 | 96 | <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
96 | 97 | for detailed information about target units.) The |
|
99 | 100 | deterministic, but still adheres to a limited amount |
100 | 101 | of ordering structure.</para> |
101 | 102 |
|
102 | | - <para>When systemd starts up the system it will |
| 103 | + <para>When systemd starts up the system, it will |
103 | 104 | activate all units that are dependencies of |
104 | 105 | <filename>default.target</filename> (as well as |
105 | 106 | recursively all dependencies of these |
106 | | - dependencies). Usually |
| 107 | + dependencies). Usually, |
107 | 108 | <filename>default.target</filename> is simply an alias |
108 | 109 | of <filename>graphical.target</filename> or |
109 | | - <filename>multi-user.target</filename> depending on |
| 110 | + <filename>multi-user.target</filename>, depending on |
110 | 111 | whether the system is configured for a graphical UI or |
111 | 112 | only for a text console. To enforce minimal ordering |
112 | | - between the units pulled in a number of well-known |
| 113 | + between the units pulled in, a number of well-known |
113 | 114 | target units are available, as listed on |
114 | 115 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
115 | 116 |
|
|
178 | 179 | <refsect1> |
179 | 180 | <title>Bootup in the Initial RAM Disk (initrd)</title> |
180 | 181 | <para>The initial RAM disk implementation (initrd) can |
181 | | - be set up using systemd as well. In this case boot up |
| 182 | + be set up using systemd as well. In this case, boot up |
182 | 183 | inside the initrd follows the following |
183 | 184 | structure.</para> |
184 | 185 |
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