computer science related thread

[selvakumar]

indha questionukum yaravadhu answer therinja post pannunga

" what should happen if the kernel attempts to awaken all the processes sleeping on an event,but no processes are asleep on the event at the time of wakeup"

I am not sure whether this can happen. Kernel controls how a semaphore and other locking mechanisms should release the processes waiting for an event. Semaphores are actually implemented at the CORE OS LEVEL. (More or less in the binary code specific for particular architecture) The release & wait are controlled by kernel. I think processes cannot come out of the sleep themselves in that case. Again, not clear. Must revisit these things

[Vivasaayi]

does anyone have the idea of why "inode" index of filesystems starts from 1 unlike the array index which starts from 0.

i need to know it urgently

I am not sure on this since I have lost my touch on kernel related stuffs. My Guess - What about super block ? For calculation of block, block 0 could be (Not sure) assigned for Super block.. illaya
Let me try.

selva,

i thought today u would be on leave.so i dint pm u.

i found the answer.

actually the boot loader file has the inode number 0.

the bad blocks are given inode number 1

i guess its correct...google panadhula...kadaiseela engeyo oru moolaila evano oruthan eludhirundhan...avana nambiten HEHE

[Vivasaayi]

indha questionukum yaravadhu answer therinja post pannunga

" what should happen if the kernel attempts to awaken all the processes sleeping on an event,but no processes are asleep on the event at the time of wakeup"

I am not sure whether this can happen. Kernel controls how a semaphore and other locking mechanisms should release the processes waiting for an event. Semaphores are actually implemented at the CORE OS LEVEL. (More or less in the binary code specific for particular architecture) The release & wait are controlled by kernel. I think processes cannot come out of the sleep themselves in that case. Again, not clear. Must revisit these things

idhethan naanum yosichen...but this question was given in the exercise of "the design of unix operating systems" by maurice j bach

naanum andha exercise ku solution key thedi salichuten.

how abt waiting for a certain period of time for the shared variable to be used by some other process and changing the variable status from a shared variable to normal variable...oru guessuthan

[Vivasaayi]

ext2fs filesystemoda inode list

The first ten inodes on the filesystem are special inodes:

* Inode 1 is the bad blocks inode - I believe that its data blocks contain a list of the bad blocks in the filesystem, which should not be allocated.
* Inode 2 is the root inode - The inode of the root directory. It is the starting point for reaching a known path in the filesystem.
* Inode 3 is the acl index inode. Access control lists are currently not supported by the ext2 filesystem, so I believe this inode is not used.
* Inode 4 is the acl data inode. Of course, the above applies here too.
* Inode 5 is the boot loader inode. I don't know its usage.
* Inode 6 is the undelete directory inode. It is also a foundation for future enhancements, and is currently not used.
* Inodes 7-10 are reserved and currently not used.

All block and inode addresses start at 1. The first block on the disk is block 1. 0 is used to indicate no block. (Sparse files can have these inside them)

shabaaa...oru vazhiya answer kandupichachu

[Raghu]

R there any SQL Server 2005 developers/dba here or Oracle developers??