Study Notes

Chkconfig: maintain /etc/rc.d directory structure, add, remove change serivce, list time stamp information. Check the state of particular service.
# chkconfig –list sendmail
# chkconfig –level 4 sendmail off

The “ntsysv” command takes the functionality of chkconfig and wraps it into an easy-to-use screen interface.

kdbconfig: set the type of keyboard, refer to “/etc/sysconfig/keyboard”
timeconfig: set time zone, refer to “/etc/sysconfig/clock”
mouseconfi: set mouse, refer to “/etc/sysconfig/mouse”
sndconfig: screen-oriented interface to make install sound card.

NT boot, NT’s loader installs to the master boot record(MBR) and relies on three major files: ntdetect.com, ntldr, boot.ini.

Once you have a working LILO boot disk, you can simply copy the boot sector from the disk instead of the harddriver,eg:
# dd if=/dev/fd0 of=/bootsect1n1 bs=512 count=1
I think the first 512 byte in /dev/fd0 may record the boot information.

RAID: Only three are implemented in Linux, linear,0,1,5
You can assign additional disks from failover, called spare disks within the RAID set, when one disk fails it is marked as bad and the data is reconstructed on the first space disk, which is used as replacement, resulting in litter or no downtime. When using fdisk to format RAID component disks, the Partition ID must be set as “FD”.
# mk2fs -b 4096 -R stride=8 /dev/md0

To check what interrupts you are using:
# cat /proc/interrrupts
i386 PC have up to 15 usable interrupts out of 16: 0-15

To get a list of IO address and DMA channels used:
# cat /proc/ioports

To check DMA resources:
# cat /proc/dma

To load modules into kernel:
# modprobe sb irq=5 io=0x220 dma=0
comment, here “sb” means sound device.

Laptops have a special peripheral interface bus called PCMCIA, that requires a special set of drivers and service to handle it. Whenever a card is loaded, you can check the “/var/run/stab”. To see waht setting your card is set to, you can issue the “cardctl” command.

Advanced Power Management(APM)
When the BIOS tells the daemon about a pending suspend or a standbycall, it immediately calls sync(and writes all cached file system information to disk immediatelly). It will then sleep for two seconds and tell BIOS to continute.

# runlevel
5 3
means, you were in level 5 last and are now in level 3.

LCD: Liquid Crystal Display

To have the kernel dynamically load and unload modules as needed, a special kernel thread, “kmod” is called upon to control the loading and unloading of modules. Refer to “/etc/modules.conf”.

To load modules on command line:
# depmod -a
# modproble eth0
Place modules in “modules.conf” to have them automatic loaded.

Two limits manage disk consumption:
1. Limit the number fo inodes a user may have;
2. Limit the number of disk blocks a user’s file may consume

Quota are enabled on a file system basis only, they CAN NOT be set on directories.