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.
185
questions
37
votes
8
answers
17k
views
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?
- 511
35
votes
6
answers
53k
views
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 ...
- 595
30
votes
3
answers
18k
views
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 ...
- 465
28
votes
2
answers
4k
views
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 ...
- 1,113
22
votes
3
answers
61k
views
Is a CMOS battery rechargeable?
Is a CMOS battery rechargeable? If so, what does its charger look like?
- 613
15
votes
8
answers
21k
views
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 ...
- 1,201
13
votes
8
answers
84k
views
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 ...
- 344
10
votes
1
answer
3k
views
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 ...
- 4,474
10
votes
2
answers
996
views
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 ...
user285705
8
votes
2
answers
1k
views
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 ...
- 1,295
6
votes
3
answers
55k
views
"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 ...
- 247
5
votes
2
answers
4k
views
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 ...
- 51
5
votes
2
answers
556
views
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 ...
- 189
5
votes
4
answers
20k
views
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 ...
- 51
4
votes
1
answer
2k
views
Can't boot up after clearing the CMOS
My computer always ask to set CMOS set up during boot up. i think my CMOS has problem and i tried to clear the CMOS by using the jumper for clear CMOS. i did not unplug the PSU when i did this and ...
- 41
4
votes
3
answers
32k
views
WIndows 10 time zone keeps reverting back
I've got a user whose Windows 10 computer won't hold the correct time zone. Specifically, the time zone randomly changes back. The user is in Pacific Time, but the laptop would have been set up at a ...
- 65
4
votes
4
answers
8k
views
CMOS Battery recharged [duplicate]
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 ...
- 51
3
votes
1
answer
2k
views
How do I find the CMOS Battery Health in a PC
This is exhausting, and I'm wondering if there is any solution.
Trying to find info specifically on my CMOS battery on my computer. It is a PC, not a laptop.
The PC is working fine, but CoPilot only ...
- 31
3
votes
2
answers
11k
views
What does this beep code mean?
When I wanted to start my laptop today (an Acer Aspire 8920G), the laptop started beeping. I know this beeping is a POST error code, but I can not figure out which one it is. The motherboard of the ...
- 95
3
votes
2
answers
7k
views
Wipe windows 10 info from bios or cmos
I've read that windows 10 writes it's registration/configuration information into the bios (or was it cmos...) of your motherboard to close the loop of using the same product key as both a dual boot ...
- 148
3
votes
1
answer
15k
views
How to reset a laptop BIOS with no CMOS battery?
I have an Asus X455LD and I tried to update its BIOS and it went wrong. The laptop turned off when the process finished, and now when I press power button it does not turn on. The power led turns on, ...
- 33
3
votes
3
answers
709
views
Unable to access my BIOS although the OS boots fine
I have an MSI GT602OC Laptop upon which I'm using an Ubuntu 15.04 (only OS). I can access my OS, it boots fine, no problems here.
But when I try to access the BIOS (through the DEL key that I used ...
- 31
3
votes
4
answers
47k
views
Forgotten BIOS supervisor password--Lenovo B570
I've tried everything possible to reset the supervisor password on my Lenovo B570 laptop: looking for a non-existent CMOS battery, trying to run some of those software tools that are supposed to give ...
2
votes
2
answers
424
views
CMOS Time problem
Whenever i switch on the system an error is showing that Date & time is not correct. I have to set the time manually in bios to work the system. What is the reason for this error. How can i solve ...
- 1,079
2
votes
3
answers
19k
views
Checking NVRAM on BootUp
I've recently encountered with my desktop the other day. the problems were like this
Computer boots up. and Shows this Message
F1 for Setup and Configuration
F2 to load default values
...
- 161
2
votes
1
answer
3k
views
Where is the CMOS setup utility stored?
I am reading an old A+ certification book that is going over BIOS and CMOS.
Some background info (this may all very well be incorrect):
From what I understand, BIOS is a set of programs on the ...
- 123
2
votes
1
answer
400
views
CMOS Battery. Forgot to put it in
Well. I am a complete idiot. I had to replace my keyboard. And the only way to do that was to completely take it apart. While I was at it I was going to replace my CMOS battery. I took it out. Went to ...
- 181
2
votes
4
answers
456
views
Home server clock runs too fast
I have a Debian server running on some hardware from ca 2004, and the real time clock is running too fast. I have set it to run ntpdate every hour, so the clock is mostly correct, but this seems kinda ...
- 720
2
votes
1
answer
2k
views
What defines a CMOS checksum in a BIOS system?
I am sure that many of you have seen and experienced the dreaded "CMOS checksum error" first hand. But what is it?
CMOS Checksum error
What is it a checksum of? The entire content of the CMOS data?...
- 20.9k
2
votes
2
answers
3k
views
How the PC boots even after the CMOS battery failure?
Whenever I do switch on, my pc boots straightaway. It doesnt wait for me to press the Power button. When I plug the cable and power on, computer also automatically gets powered. So I replaced the CMOS ...
- 915
2
votes
1
answer
986
views
Does removing CMOS battery clear CMOS?
I thought CMOS battery kept CMOS memories alive. In light of this, I find this section of my SuperMicro motherboard's manual puzzling:
Why remove the battery and then short some connections? Wouldn't ...
- 524
2
votes
2
answers
20k
views
Can you remove the CMOS battery from a powered computer?
I want to take out the CMOS battery while my machine was working to check how much charge it had left in it and I'm curious whether it's going to whack my CMOS settings.
Does the BIOS chip draw power ...
- 21
2
votes
1
answer
5k
views
Can laptops run without a Cmos Battery
So while I start the process of getting a new cmos battery. Will my laptop run without one if I remove the old one? Since a lot of you said it might leak can I remove it and still run?
- 43
2
votes
3
answers
9k
views
Motherboard keeps giving checksum error after installing new battery
I am repairing a computer with an ASUS M2NBP-VM CSM ACPI motherboard (I am not sure this is the correct description of the motherboard but, at least, this is what gets printed to the screen during ...
- 207
2
votes
2
answers
2k
views
PC Stuck on verifying DMI pool - taken many steps
I have an old computer I am attempting to restore. It's a msi 945g series chipset board. I began with no POST beeps and no monitor signal being detected.
I have....
Removed, Cleaned and Reseated ...
- 169
2
votes
1
answer
963
views
What is the rationale behind the default values for adjtimex --adjust?
The adjtimex utility has an --adjust mode that can be used to compare the system clock with the CMOS clock, calculate suggested values for the tick and frequency offset kernel time variables, and ...
- 515
2
votes
1
answer
1k
views
How can I restore my Lenovo T500 to Switchable Graphics without being able to see the screen?
I changed my Lenovo T500 from 'Switchable Graphics' to 'Discrete Graphics' in the BIOS.
Now I don't get any display out on the internal LCD, or an external VGA monitor. Not even the POST screen.
How ...
- 181
2
votes
1
answer
2k
views
CCD vs. CMOS webcams [closed]
Several years ago, I tried a CMOS-based webcam and it really sucked. It needed an extremely brightly-lit room to work. Around the same time, I also tried a CCD camera and it worked great. But since ...
- 14.3k
2
votes
1
answer
2k
views
CMOS checksum error after upgrading BIOS and clearing CMOS
The system is a Gateway DX4831-3, with a MB.GAJ09.001 motherboard. The updated BIOS is revision P01.B1, downloaded from Gateway's website in the support/drivers section.
I was able to flash the BIOS ...
- 191
2
votes
0
answers
168
views
There are two PSW switches on this motherboard. What are they for?
Im checking out the motherboard on an Asus Vivo AiO (all-in-one) computer. The computer model is: m241. The motherboard model is: V241DA.
Originally, I'm having an issue viewing BIOS, POST, Advanced ...
- 21
2
votes
0
answers
188
views
PC double boots before POST, then boots normally
When turned on from any power state (S1-S5), including sleep modes, my PC turns on, then off, then back on and boots as if from shutdown, thus losing work and closing programs. The shutdown occurs ...
- 21
2
votes
0
answers
3k
views
Thinkpad T410 not booting: Simple solution?
I have a Lenovo Thinkpad T410 which I left outdoors overnight after a BBQ... No rain but likely some humidity.
Symptoms?
- Initially, screen remains black, nothing happens upon pressing power button....
- 21
2
votes
1
answer
2k
views
PC won't start unless I reset CMOS
Situation: My PC is dead in the water. Both power buttons (Case/MB) have no effect. If I pull the power cable, reset CMOS, reconnect the power cable, then press either power button the PC fires right ...
- 850
2
votes
0
answers
174
views
Clearing the CMOS fixed my computer but I want to know why it was necessary
After a shutdown my PC would turn on, but would not boot (nothing appeared on the monitor). I cleared the CMOS on my motherboard via the jumper, and then was able to enter the BIOS setup menu and ...
- 21
2
votes
1
answer
2k
views
Toshiba Laptop Not Retaining BIOS
We have a Toshiba Satellite L50-C-1FR laptop.
For some reason, one day it stopped retaining all the BIOS information (time, date, etc). The info has to be set every time it's booted. The first thing ...
1
vote
4
answers
27k
views
Remove BIOS password on netbook
A friend of mine asked me me to fix her daughters netbook. It has a BOOTMNG missing error, so I decided to install windows again. But, windows is not installing, because the BIOS has a password, and ...
user149961
1
vote
4
answers
5k
views
Why won't my ASUS P5MT-M motherboard allow me to enter the CMOS setup?
When the system POSTs, it doesn't display any options for entering the system setup.
The official manual for this motherboard claims that you need to press <Del> to enter setup, and I've ...
- 1,052
1
vote
2
answers
24k
views
Do modern laptops with non-removable battery still retain the CMOS battery?
Today, laptops with non-removable batteries are becoming more and more common due to a pressure to make laptops lighterweight and thinner.
Historically, computers have had a CMOS battery to operate ...
- 2,004
1
vote
1
answer
66
views
Is there an un-bypassable way to protect my bios settings?
Is there a way to protect my bios settings beyond any sort of method of bypassing? I just set a long bios password but if it as easy as merely removing the CMOS battery to bypass the password, what ...
1
vote
1
answer
1k
views
What used to happen when the non-rechargeable CMOS battery ran out?
I'm taking a uni course on electrical engineering and my textbook says that the CMOS battery used to last between 2 and 10 years. Since preserving BIOS settings seems quite important to me, I was ...
- 152