Good afternoon,
In the "f24 boot fails; need help" topic, a log file extract had these 2 lines:
1533 [ 4.022605] coyote systemd-fsck[428]: /dev/sda6: Superblock last mount time is in the future. 1534 [ 4.022745] coyote systemd-fsck[428]: (by less than a day, probably due to the hardware clock being incorrectly set)
One person noted "The time problem suggests that the little pancake battery on the MB that maintains the clock might be out of juice. I think these are 2032 style for PCs. It would be a good idea to replace it."
I responded "I didn't know workstations nowadays had batteries. When the system is back on its feet, I'll try to check that. It was bought in 2013."
I knew that the older motherboards had batteries. But I thought the newer ones used something like flash (or other persistent) memory. It did not occur to me that booting might want the date/time before the boot process reached the point of being able to access the internet.
Two people corrected me. Someone else in the discussion said it well: I sit corrected!
Fedora seems to have a huge number of commands. Does Fedora have a command to report the condition of a full-sized tower motherboard battery? If yes, what is that command?
thanks, Bill.
On Thu, 18 May 2017 16:25:34 -0600 William mattison.computer@yahoo.com wrote:
[snip]
I knew that the older motherboards had batteries. But I thought the newer ones used something like flash (or other persistent) memory. It did not occur to me that booting might want the date/time before the boot process reached the point of being able to access the internet.
The kernel sets system time from the saved time, and then corrects it from the web when net access is up. If it is too far off, it won't correct it.
Fedora seems to have a huge number of commands. Does Fedora have a command to report the condition of a full-sized tower motherboard battery? If yes, what is that command?
I am not aware of any way to do that, though I haven't checked the BIOS on boot to see if that voltage is displayed. A quick web search turned up nothing. The battery is only a buck or two, and they are sold even in some grocery stores. It might be a little aged on the shelf, but should still do the trick. CR2032 is the one you want.
Allegedly, on or about 18 May 2017, stan sent:
The kernel sets system time from the saved time, and then corrects it from the web when net access is up. If it is too far off, it won't correct it.
Hey, what?!
You can't set a clock from a stored value, time is a moving thing, it's (now) not going to be what the time *was* when you shut down.
The hardware clock runs continuously. The system reads it at start up, eventually sets the software clock from it. Can tinker with it while the system is running, to keep it accurately in sync with real time. May completely ignore the hardware clock while the system is running. Can set the hardware clock to precise real time from the software clock before shutdown.
While its true that if the clock is wildly out, for some unknown reason, that some OSs may kick the clock forward to the time last logged on the harddrive somewhere. It's not a particularly good solution. And certainly not how to set a clock.
As for checking the status of the battery. Most BIOSs had a screen that showed you system voltages, somewhere, including the battery. There are various system probing utilities that your OS can use to see things like CPU temperatures, fan speeds, etc. There may be an accessible sensor for the battery.
But consider this: The shelf life of some of these batteries is 5 to 10 years. That's stored, unused, in its packet. Your system is using the battery. If it's around three years old, then replacing it to see if things improve is a reasonable thing to do.
On Fri, 19 May 2017 23:22:30 +0930 Tim ignored_mailbox@yahoo.com.au wrote:
Allegedly, on or about 18 May 2017, stan sent:
The kernel sets system time from the saved time, and then corrects it from the web when net access is up. If it is too far off, it won't correct it.
Hey, what?!
You can't set a clock from a stored value, time is a moving thing, it's (now) not going to be what the time *was* when you shut down.
The hardware clock runs continuously.
Good catch! Wasn't thinking too clearly, obviously. :-)
On 18 May 2017 at 23:25, William mattison.computer@yahoo.com wrote:
Fedora seems to have a huge number of commands. Does Fedora have a command to report the condition of a full-sized tower motherboard battery? If yes, what is that command?
I don't think there's any way to check on the status of a motherboard battery short of removing it and putting a meter across it, but you can monitor the CMOS clock and get an idea of how well it is performing using the "chronyc" command line tool included as part of the "chrony" package. The bits you are interested in are the Frequency value in the system clock tracking - the further from zero in ppm, the worse the clock is performing - and the RTC data. Run chronyc from a shell, then enter the commands "tracking" and "rtcdata" (without the quotes) at the chrony> prompt. "quit" or "exit" will return you to the command prompt, "help" will provide info on other commands, or see the man page for chronyc.
I'd start by checking the clock in the CMOS on a reboot though - it could just be that it has somehow ended up several hours out from what it should be, but is actually keeping fairly good time and has a decent battery. Sync it up to the actual time, run the system for a few days, then see what chronyc reports for the tracking - if it's not doing well, then a new CR2032 battery a good next step.
Allegedly, on or about 18 May 2017, William sent:
"I didn't know workstations nowadays had batteries. When the system is back on its feet, I'll try to check that. It was bought in 2013."
I knew that the older motherboards had batteries. But I thought the newer ones used something like flash (or other persistent) memory. It did not occur to me that booting might want the date/time before the boot process reached the point of being able to access the internet.
You can't store time. It's continuously changing.
There are a few ways of keeping a clock ticking while the power is off:
Run the clock off a watch battery, and most systems do. It's always running off the battery, even when the mains power is applied. It keeps the clock independent.
Do so with a rechargeable battery, that the system recharges when it's running. My sister's ancient Mac did that. I think at least one of my Amigas did, too, if I recall correctly.
Use a super-capacitor. One that can hold a charge for a very long time. Many VCRs used to do that. They're usually powered up all the time, but used the super-cap to keep the clock running during power-outs, and saving people the headache of resetting the clock if they needed to unplug and move their VCR. Most computers are at least partially powered up all the time (since few people actually switch them off at the wall), or are powered up often enough to keep the clock running until the next time that you switch on, so this is a mostly viable option.
But the first option is going to be the most common approach in the PC world.
After groping through papers in a moving box, I found the user's guide for the motherboard. Amazing: something I kept actually proved useful! It's a ASUS Sabertooth Z77, bought in early 2013. Well, no index, no mention of battery in the table of contents. I skimmed through once, no hint of battery. I went back to the diagram of the motherboard, grabbed the magnifying glass, and behold - in very teeny print, a circle labelled "Lithium cell CMOS power". Rick Stevens said in another topic posting "Memory is the second thing to go, but I can't remember the first!". Maybe vision is the first thing to go? Y'all are correct: the motherboard does have a battery.
The ASUS website showed how to change the battery, but that's all. Oh yes: it's a CR2032 3 volt Lithium ion battery as some of you said.
I'm not really concerned about the $ cost of a new battery. I am concerned about BIOS settings disappearing the instant the battery comes out, and therefore what else I might have to do before and after the battery change. This seems like another high risk task. I think the user's guide mentioned a way to copy BIOS to a flash stick, and read BIOS from a flash stick. I'll have to study this properly before I actually do anything.
I did not see any indication of battery state in the BIOS display. I'll have to install the chrony package and give it a try.
Is there a Fedora command to display the appropriate BIOS settings that I may have to restore after replacing the battery?
thanks, Bill.
Allegedly, on or about 19 May 2017, William Mattison sent:
After groping through papers in a moving box, I found the user's guide for the motherboard. Amazing: something I kept actually proved useful!
When space permitted, I'd ziplock bag things like that, and jam them into the PC case, ready for the next hiccup. Nine times out of ten that I might fix a doozy of a problem in a PC it involved dragging the box out and opening it, and the things I might need to read are waiting.
Good evening,
Hardware problems have seriously tied me up for about a week now. My apologies for my silence on this topic.
It turned out I already had the chrony package. I ready chronyc's man page. I tried it. But I saw no chronyc parameter or option for showing CMOS clock statistics.
It took about a week of trying, but I did finally get into BIOS. The clock was about 5 seconds slow. The voltages all looked fine.
A problem similar to what triggered this topic occurred last Thursday. It does seem to be the battery and the CMOS clock that's causing the trouble. So let's close this topic. Further discussion is in the topic "post-mortem: f24 boot fails; need help.".
Thank-you for your help. Bill.
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Andy Blanchard -
stan -
Tim -
William -
William Mattison