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For resetting bios password we used to relocate jumper and reset it,How does changing jumper helps in resetting password?
What happens to Bios password while we change jumper ,how does the manual hardware (jumper) relocation changes/resets the password?
BlueBerry - Vignesh4303
Posted 2013-08-26T05:06:23.670
Reputation: 7 221
4
It simply wipes out the volatile part of the memory of the bios, leaving a pristine, default set of settings, including an empty password. I believe it does so by disconnecting the power from the bios, which should be the same as removing the battery, and waiting for any residual power to drain out. This is why you need to do so with the system switched off.
Journeyman Geek
Posted 2013-08-26T05:06:23.670
Reputation: 119 122
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Removing the jumper breaks the circuit the CMOS needs to retain data. Moving the jumper grounds out any residual charge. After returning the jumper to the original position and powering up, the default settings are restored to the CMOS from the EEPROM that was set at the factory. Some devices store passwords in the EEPROM, in which case moving the jumper will not reset the password (or any data stored in the EEPROM).
one.time
Posted 2013-08-26T05:06:23.670
Reputation: 623
Its simply a convenience feature. – Keltari – 2013-08-26T05:10:57.460
As an aside, some systems with TPM Chips will store the password in non-volitile memory so even if you move the jumper or remove the battery it will still preserve the password lock. – Scott Chamberlain – 2013-08-26T05:22:52.120
1Also, the main reason they use volatile memory (despite the prevalence of non-volatile memory these days) is for safety. If you mess up your configuration settings or forget the password, you can simply remove power to reset it - this mechanism does not depend on your computer being in a working state. It's still reasonably secure - the first rule of computer security is that hardware access is full access (with the partial exception of full disk encryption), but you'll still know if someone has reset it (tamper evident). – Bob – 2013-08-26T05:53:02.653