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--- notes:lpic-1_notes [2026/06/12 09:54]
103.173.138.215 old revision restored (2026/05/27 23:57)
+++ notes:lpic-1_notes [2026/06/13 20:26] (current)
216.73.216.69 old revision restored (2026/06/12 15:49)
@@ Line 76: / Line 76: @@
   * Runlevels - 0=shutdown, 1/s/S=single-user_maintenance, 2=multi-user, 3=multi-user_no-X, 5=multi-user_with-X 6=reboot
   * On Debian, 2 is default and 3,5 are not used. On Redhat, 3 is the default.
+  * /etc/rc script to change runlevels on redhat (also init/telinit script)
+  * /etc/rc.sysinit (Redhat) or /etc/init.d/rcS (Debian) - system init script launched by init before system daemons
+  * /etc/rc.local- local startup actions called at end of startup
+  * /etc/init.d contains startup/shutdown scripts for all system services
+  * /etc/rc0.d - /etc/rc6.d contain softlinks KNNservice or SNNservice specifying whether to start or stop services and in what order for that runlevel (done by init process). Kills done before starts.
+  * /etc/inittab contains "id:N:initdefault:" for default runlevel N
+  * //runlevel// shows current and previous runlevel
+  * //shutdown [options] time [warning message]//  - -f=fastboot -h=halt -r=reboot -F=force-startup-checks -k=just-send-warning . Time is "now" or "+N" in N minutes or absolute time e.g. 23:58.
 ==== 102 Installation and Package Management 18% ====
@@ Line 85: / Line 92: @@
   * Knowledge of basic features of LVM
   * Terms: / (root) filesystem, /var filesystem, /home filesystem, swap space, mount points, partitions
+==Notes==
+  * choosing a disk layout for linux depends on amount of disk space, purpose of the system, size of the system and backup strategy. Some general guidelines are
+    * If diskspace is limited, just /boot, / and /swap
+    * /boot is a separate 50MB partition because older kernels/BIOS require kernels under a 1024 cylinder limit.
+    * For larger systems keep / smaller/simpler to reduce risk of corruption.
+    * Can use separate partitions for /var (to isolate system logs), /tmp (to isolate tempfiles), /home (for backup and RAIDing of user's data)
+    * Using a separate partition for /usr allows it to be shared via read-only NFS which allows for saving space and easier maintenance of apps/updates.
+  * Superblock on filesystem contains critical metadata so multiple redundant copies are kept.
+  * Filesystems must be mounted (listed in filesystem table) before being accessible. /etc/fstab is a list of filesystems to mount on boot up.
+  * Master Boot Record on first 512 bytes of first sector of disk contains info on partitions and bootup. Can be backed up and restored with <code>
+dd if=/dev/hda of=~/mbr.txt count=1 bs=512
+dd if=~/mbr.txt of=/dev/hda count=1 bs=512
+</code>
+  * To backup/restore just the partition layout, use sfdisk <code>
+sfdisk -d /dev/hda > partition_backup.txt
+sfdisk /dev/hda < partition_backup.txt
+</code>
+  * Linux may also be booted from Live USB which allows for persistent modifications. If the BIOS does nto support this, a bootable CD can be used first.
+  * Swap space allows main memory to be temporarily copied to disk. As a starting point set swap to twice the memory size (at least the same size).
 === 102.2 Install a boot manager (LCN-5 CTL-5) ===
@@ Line 110: / Line 138: @@
   * Determine what files a package provides, as well as find which package a specific file comes from
   * Terms: rpm, rpm2cpio, /etc/yum.conf, /etc/yum.repos.d/, yum, yumdownloader
 ==== 103 GNU / Unix Commands 43%   ====

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