OT: Can CMOS battery on PC motherboard be hot-swapped?

That works, but is full of traps that are often difficult to diagnose. The most common example is resetting the CMOS and discovering that the previously functional hard disk will not boot. On todays machines that is usually the SATA mode of either AHCI or ATA Emulation (or RAID if applicable). In the distant past, it was LBA mode. There are other (video window size, com port assignments, parallel port mode, etc) that will cause problems if reset to default.

speaking NTP is half of the solution, clock scaling is the other half. without clock scaling you get serious jitter each time the clock is resynchronised.

microsoft calls it internet time, it's in the clock control panel somewhere

The XT dodn't have an RTC, DOS would by default ask you the time on boot (all XT the clones I encountered did have an RTC but needed a vendor specific app to update the DOS clock from the RTC) the clock was in the I/O address space

AIUI the first PC compatibles from IBM to ship with RTCs were 80286 based, but IIRC the 8086 based PS/2-30 had one too.

Last week I was able to reset the CMOS on a modern (2012) board by shorting the battery contacts. I can't say for sure that Foxconn wasn't emulating CMOS by detecting the short or the loss of clock power. but It sure behaved like it was actual CMOS.

I had configured the bord in such a way that the onbord display hardware was inactive and I needed to get it back, a brief visual search of the board didn't reveal a CMOS reset jumper.

Your Internet connection has latencies and jitter as well.

see what the FCC says about your hooks.

See who they say the best is.

I get 24 down and send 20 up, and have 36ms latency with 2ms jitter.

Damn near T3. Not bad for $50 a month.

Yes, but sometimes you have no choice. The dying battery has scrambled the contents, and the default gets you close. The one that got me the first time was the motherboard booting too fast for an older hard drive, and having to turn the memory test on in the BIOS to slow it down. That was early Pentium boards, if my memory is correct.

Some did. Some were on the clone motherboard, some pluged in under the BIOS Eprom and some were on a card. The cards were good sellers.

hard

Squad

has

It has a line cord and brick for doing the SPICE runs. Other than that i seem to get over 5 hours no problem.

?-)

The way to really get the point across to the is to force them to use only the green products that are seriously inferior.

?-)

those out.

ritual

battery

there

long

write

totally

The

I'll check my manuals, but it is more difficult to make static ram that needs battery than a bit of flash. Look at the common PICs, AVRs, and such; very many have flash, none have static ram requiring battery.

?-)

they say I've got 4ms jitter not bad for the other side of the world,

I pay about half that, for a slow DSL connection.

to nz.pool.ntp.org I get ICMP pings between 34.7 and 35.8 ms (6 hops). and TCP pings in the same ballpark.

OTOH to the national standard I get 5ms jitter

I haven't bothered to optimise my NTP settings I'm still using the defaults. which is pick 4 servers at random from an international pool.

I usually try to set things up to work with the defaults anyway.

The battery. Make sure you have a good hold on it before removing & replacing. If you drop it on an a energized circuit you can short something out.