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Questions tagged [cmos]

CMOS (stands for complementary metal-oxide-semiconductor) is a type of technology used in the manufacture of integrated circuits which include elements of digital logic.

191 questions
37
votes
8 answers

How can a CMOS battery store data?

How does a CMOS battery store information on it? I know it stores information such as the time, date, passwords and drive configuration, but how? How can a battery store data?
ryryan
  • 511
36
votes
6 answers

Windows 10 time falling an hour behind when dual booting

I've checked and my BIOS clock stays correct so it can't be the CMOS battery. Also when I boot Windows 10 and the clock is an hour behind if I got and sync the clock with the time server it shows correctly. So I'm not sure what could be causing the…
jshbrntt
  • 605
30
votes
3 answers

Why do PCs still require a CMOS battery?

Why do PCs still require a CMOS battery, given that they're already plugged in? We are providing lots of power to the PC by plugging it into AC mains electricity, so why does it still require a CMOS battery?
Joseph Philipson
  • 465
28
votes
2 answers

When I hit DEL during start up, am I entering CMOS or BIOS?

For the longest time I assumed I was entering the BIOS setup and CMOS is a chip that holds the settings I set in BIOS in its memory. I recently read somewhere that when I am configuring the boot order and etc, that that's actually CMOS setup. I'm…
Space Ghost
  • 1,113
23
votes
3 answers

Is a CMOS battery rechargeable?

Is a CMOS battery rechargeable? If so, what does its charger look like?
Timo Huovinen
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17
votes
8 answers

Checking CMOS battery without going into the BIOS

Today, I found my Windows 10 date and time too far ahead by about 26.5 hours. The time zone is fine, and I corrected the problem by clicking on a "Sync" button to sync with a Microsoft server. Googling indicates that the problem might be caused by…
user2153235
  • 1,543
13
votes
8 answers

How long does CMOS battery (3V) on a motherboard last?

Just wondering usually how long does CMOS battery last on a regular motherboard? I read that motherboard leakage current of about 3 - 6 micro ampere. I did a calculation below but I believe that i may have missed something. What is the minimal…
Kevin H
  • 364
10
votes
1 answer

What "TYPE" of harddrive is in my old 286

I have a very old(1989?) 80286 computer. I can tell it was a very good machine in it's day. It has a harddrive installed. I finally got a PS/2 to AT keyboard plug today and got it to boot. Now I have a problem though. It's CMOS battery must've died…
Earlz
  • 4,564
10
votes
2 answers

How can I re-program/flash a backup of the bios?

I have some computers that have a particular bios setting that keeps everything running smoothly. The setting is not the default setting for the motherboard. So, when the CMOS battery dies, the setting is erased and causes the user problems. How…
user285705
8
votes
2 answers

Monitor is blank (no signal)

Custom built desktop computer. It was working fine (used as a server), but I needed to change the IP address, so for the heck of it, I went into the BIOS and: Loaded factory defaults Changed video from PCI Express to on-board VGA Saved settings…
JohnB
  • 1,305
6
votes
3 answers

"Please enter SETUP to recover BIOS setting" message on boot

When I boot the PC it gives the following error: Please enter SETUP to recover BIOS setting Press F1 to run SETUP Press F2 to load default values and continue I have tried to set these settings, but it come out every boot time. It can't save these…
plaidshirt
  • 247
5
votes
2 answers

How to fake having a CMOS battery for RTC

I have an embedded computer running Ubuntu Server 14.04 that has no CMOS battery (temporary, I hope) so it always boots to December 31, 2008 ... Currently I'm developing an application that depends on some installed hardware. I start Gnome from the…
Nate Lockwood
  • 189
5
votes
4 answers

How to reset BIOS on ASUS F5?

My BIOS is password-protected, so that I can't access the BIOS settings (I don't have problems with booting into Windows XP). The BIOS is made by American Megatrends (AMI). I've been trying some utilities to reset the BIOS from Windows, but I don't…
Alexandru
  • 51
5
votes
2 answers

Laptop BIOS clock resets on reboot?

I have a fairly new Sony Vaio laptop that had some power problems, and they put in a new motherboard yesterday. It fixed my old problems, but now the clock is acting weird. The BIOS clock gets reset whenever I restart the computer, and the Windows…
kurthc
  • 51
4
votes
4 answers

CMOS Battery recharged

My pc was unused for several months(its a 5 year old acer desktop) and on boot up a screen came up indicating that the CMOS battery was low. Any time I restarted, as expected, the same screen came up and the time and date reset. However, I left the…
Alex Roy
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