what is file system?what are the different types of file systems in solaris?

File system is collection of control structures used to store data in a efficient way.
3 types of file systems
  1)Disk based FS
   2)Distributed FS
   3)Virtual file systems

1)Disk Based FS:-
    UFS-unix file system.used to access the data from the disk.
    hsfs-high seira file system.used to access from cd-rom
    udfs-Universal device file system.used to access the DVD roms
    pcfs-personal computer file system.used to access the flash drives and usb's
2)Distributes file systems:-
    NFS and Autofs
3)Virtual based file system
    1)procfs-process file system.it contains process ids.
    2)devfs-it contains all device drivers information in directory /devices.
    3)swapfs-if ram is fulled then it access from swap.
    4)mntfs:-currently mounted file systems
    5)tempfs:-when we create any thing in this directory.it not permanent.when we reboot the system it is empty.

OK boot prompt commands in Solaris ?

By giving #init 0 it goes to ok boot prompt or by pressing stop+a.

Following are the some commonly used ok boot prompt commands

ok .speed--------->display processor speed

ok .enet-addr------>display MAC addresses.

ok show-devs------>display all connected devices.

ok show-disks------->display disks connected

ok devalias------------->display all device alias names.

ok setenv auto-boot?true----->giving default auto-boot is true.

ok probe-scsi----------------->display only locally connected devices.

ok probe-scsi-all------------->display all devices connected to internal and external.

ok reset-all---------------------->reset prom settings by default.

ok watch-net------------->check the network card statistics.

ok boot -r ------->reconfigure at boot

What is soft link and hard link?

Hard link:-Two files which are having same i-node number.when we update data in a source file ,the same data can be accessed from target.if we delete the source file we can retrieve data from target file due to the same i-node value.
Hard links are applied to files not for directories.
syntax:# ln  <sourse>  <target>

Soft link :-It is a symbolic link and acts as a shortcut.two files which are having soft link will have different i-node values.if we update any thing on source access from target.but if we delete source file,target file does not exist.due to the different i-node number.
syntax:-ls -l <source> <target>

What is RAID5 ?

RAID5 refers to a type of RAID that involves block-level disk striping with distributed parity. In this configuration, every drive except one must be functional for the RAID to be operational. If a second drive fails, data loss is likely to occur. Block-level disk striping refers to blocks of data being stored sequentially across drives. Blocks include multiple bytes of data. Distributed parity refers to parity data spanning across all drives in the array, not just being stored on a separate disk. RAID5 is supported by FreeBSD, Linux, Microsoft Windows server operating systems, NetBSD, OpenBSD, OpenSolaris and Solaris 10.

In solaris how to find used and free inodes?

#df -F ufs -o i

Boot process in Solaris

Following is the Boot process Phases  in Solaris
1)Boot PROM phase
2)Boot program phase
3)Kernel initialization
4)Init initialization

Boot PROM phase:-
  When we power on the system it displays banner.Banner includes prom version,host id,MAC address,memory.After displaying banner to start POST(power on self test) to all connected hardware devices.then it start boot program phase.

Boot program phase:-
  Here it looks for default boot device and start reading boot program.boot program is located in 1-15 sectors of the hard disk.it contains UFS file system.it is responsible for to load the secondary boot program called UFS Boot loader.

Kernel initialization:-
  Ufs boot loader loads kernel in to memory.after loading the kernel it unmaps the ufsbootloader for loading and locating  o.s modules to get control over the o.s and start mounting the root file system.

Init initialization phase:--
   Here it starts /sbin/init process.which invokes /svc/lib/svc.startd process responsible for following.
     ->mounting all the F.S
    ->configuring all network devices
    ->Enabling all services
    ->run rc script to bring the machine in to multiuser mod.

In solaris10 svc.startd acts as a separate booting phase