computer science related thread

[Vivasaayi]

hardware or software

front end or backend

anything related system can be clarified here

[Designer]

Hi Vivasaayi, there's already a similar topic here if you would like to post some info -

http://forumhub.mayyam.com/hub/viewtopic.php?t=9715&postdays=0&postorder=asc&start=0

[Vivasaayi]

but that thread was more like for endusers...not regarding programming i thought :confused2:

[Sanjeevi]

but that thread was more like for endusers...not regarding programming i thought :confused2:

This is programming related-a? :)

appadina I am more familiar with C# and .net

[MADDY]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

[Thalafanz]

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

Reboot is something like setting the system back to its normal/functional state. Or I shall say 'reset'. So, thats why it works. Just my opinion.
Maybe others can come up with more good explanation(s). :)

[littlemaster1982]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

Sometime back, my uncle called me from my home saying that our TV remote has gone crazy (When the volume button is pressed, the channel got changed). Not having a clue, I asked him to remove the batteries and put it back. It worked!!!

[Wibha]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

Sometime back, my uncle called me from my home saying that our TV remote has gone crazy (When the volume button is pressed, the channel got changed). Not having a clue, I asked him to remove the batteries and put it back. It worked!!!

my friend told me to do the same for calculator.........he never explained why :?

[anbu_kathir]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

Sometime back, my uncle called me from my home saying that our TV remote has gone crazy (When the volume button is pressed, the channel got changed). Not having a clue, I asked him to remove the batteries and put it back. It worked!!!

my friend told me to do the same for calculator.........he never explained why :?

Google vaazhga. :P.


Rebooting your computer is the most common first-step remedy for most PC ailments. Rebooting returns all of your computer's software (and hardware) to a known initial state, which in theory should eliminate fluctuating problems. The issue could be as simple as a software error or as complex as a motherboard or hard drive failure, but you really can't narrow down the options until you try a few things.

Since you have to take a logical scientific approach to identify the true source of your computer's problems, you should really eliminate all "unknowns" that could possibly exist when trying to get your computer back to a previous "known" state. For example, there could be some hardware that is "stuck" that causes a Blue Screen of Death, and it won't fix itself until the card is powered down (i.e. a hard reboot)... all the soft reboots in the world will not fix the problem.

You may have to wait a few seconds before power is completely exhausted. You may have heard the tech support guy from India state that "you need to wait 30 seconds before you turn your computer on", and there is some truth to this. The large capacitors inside your PC's power supply store electricity (which is why it's dangerous to touch them even when the power is off), and they can take some time to discharge. Thirty seconds may be a little excessive, though... my motherboard's LED usually goes out within 5 seconds.



Love and Light.

[Vivasaayi]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

i think u ask this...if im elimentary pardon me :D

normally the application crashes due to the incorrect access of data or storing data in incorrect address inside RAM.Shortly,its accessing or writing data in address space of other programs .so when the code sections of a program inside the ram is overwritten by some other program the application crashes.

the memory dump can be viewed to see what has happened when the applications crashed.

to overcome this,when a system is reboot the RAM is completely cleared and refreshed.the programs are newly loaded from the hard disk to the fresh and clean ram.In short,the program that is corrupted was removed completely from the ram(ofcourse along with all other programs) and the the program in loaded from the harddisk to the RAM newly.

now when the code that is corrupted is that of the OS(kernel),then its os crash.

idha pathithana ask paneenga

[MADDY]

appadina I am more familiar with C# and .net

i'm with ESPN and SUNTV programmes :) ...

as a sys admin, i have never been able to give a convincing answer to any of our clients/IT managers as to why "reboot always works" from a calculator to high end super dome servers :roll: :lol: ......can anyone explain here :wink:

i think u ask this...if im elimentary pardon me :D

normally the application crashes due to the incorrect access of data or storing data in incorrect address inside RAM.Shortly,its accessing or writing data in address space of other programs .so when the code sections of a program inside the ram is overwritten by some other program the application crashes.

the memory dump can be viewed to see what has happened when the applications crashed.

to overcome this,when a system is reboot the RAM is completely cleared and refreshed.the programs are newly loaded from the hard disk to the fresh and clean ram.In short,the program that is corrupted was removed completely from the ram(ofcourse along with all other programs) and the the program in loaded from the harddisk to the RAM newly.

now when the code that is corrupted is that of the OS(kernel),then its os crash.

idha pathithana ask paneenga

yes u r 100% right - and nothing is elementary in computer world :wink: ..........and anbu_kathir's link was also very informative...thanks :)

i dont know how it explains reboot of calculator or some storage boxes which just have a processor and disk arrays :roll:

[Vivasaayi]

MADDY,

calculator also has memory.when u reset the calc with the pin backside the calc the memory is reset back to the factory settings.

calculator has an embedded os in it.Its is a typical example of embedded system.embedded system is the deicated operating system as u know.

it handles the input,output and memory operations

just like computer.but a dedicated operating system-embedded system.

:D

[app_engine]

This is a "sametime connect" question -

At times it "hangs" (means I cannot invoke anyone for a chat window while sametime shows all of them as active - green squires).

What is the command line option to reset and restart sametime? I didn't know and had to reboot the computer this morning:-(

(Similar thing also happens at times with the lotus notes and I used to reboot...then one lotus notes guy helped me with the command line option : cd \notes and then nsd -kill. Is there a similar kill to sametime and if so what is the command?)

The above example also illustrates that sometimes it could be a bug in the application that "hangs" it (not related to RAM clash or HDD error). We can continue to use the machine for other apps, but if we want the specific app, reboot helps (i.e. if we don't know to kill the specific executable to restart the app).

[app_engine]

I have observed that sometimes such bugs (like the one above with sametime and notes) are not related to the main functionality of the app but the interaction with the network device on the machine and the server. Mostly related to "reconnect" errors. 99 times out of 100 they reconnect properly (when we disconnect lan cable and reconnect or get out of a "good-wireless-signal" range momentarily and then get back in) but occasionally 'hang':-(

[app_engine]

Digital telephone systems (telephone exchanges and other switching equipments) are another example of embedded systems (most of them using realtime OS) and often prone to "hanging" (my experiences were with a lot of beta systems and situation is much worse there).

AhAh, andha 'reset' switch mattum illAtti, life rombakkashtam:-) Sometimes when I'm stuck with some real-life problems, I wish there is a reset switch:-))

[Vivasaayi]

Anyone into Embedded systems here

[app_engine]

[quote="Vivasaayi"]Anyone into Embedded systems here[/quote

I was, i.e. till 2002.

[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 :?

[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"

:roll:

[selvakumar]

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.

[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"

:roll:

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 :oops:

[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 :D 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"

:roll:

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 :oops:

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

:oops:

[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??