CMOS checksum

catford

p c failed to boot up twice-then 3rd time gave the message CMOS checksum error default loaded.what does checksum error mean??

choosewisely

It means the BIOS has lost it's settings and has reverted back to it's factory default. You may need to enter the BIOS setup and reset the time, hard disk setup etc. If it keeps happening you probably need a new CMOS battery.

Genghis

catford wrote:

what does checksum error mean??

The checksum is just a basic function which checks a message before and after its sent to ensure its the same size.. if its not, its assumed there was an error along the way.

In a nutshell.. when a message is sent, a number is generated relating to the size of the message in bits and is sent with the message.. and when the message is received, the receiver recreates the number based on the number of bits received and compares it with the number sent.. I think..!

boogiemaster

It just checks to see if you have added any new hard drives or CD ROMs.
It stores your settings and the battery backs them up.
If the battery is low? You will loose the settings and it will load defaults from factory.

catford

and if the numbers dont match---checksum error!! thanks ghengis,easy when you know how!

catford

new battery for us then?its the big watch type job isnt it?-what voltage? or are they all different??

choosewisely

3v type CR2032 usually - probably worth checking your old one if you have a voltmeter first.

Sometimes it can be a loose connection so check the springy bit of metal that is holding it in too.