topic Re: 4105A/4106A battery life in Operating System - OpenVMS

4105A/4106A battery life

Sunil_uk — Tue, 10 May 2005 05:12:16 GMT

Can any one give a clue on

What is the recommendation for replacing the RTC battery on VAX4105A/4106A servers.
What is the life time of a battery on a 24/7/365 days online working setup.?

Re: 4105A/4106A battery life

John Gillings — Wed, 11 May 2005 00:20:00 GMT

Sunil,

Difficult to say. Some last a few years, some last for decades.

If the system really is 24x7x365 then you don't really need a battery, as it's job is to keep the clock accurate when power is removed.

Apart from physical removal and testing, the only way to check that your battery is good is to power down the system for an hour or so and see if it asks for the time when it reboots.

If you have a mission critical system, I'd recommend you find the price and availability of batteries, so you can make a sensible decision balancing the cost with the cost of having a system boot with a bad or inaccurate clock. You may decide to change the battery regardless of its state during periodic maintenance (say) every 2 years.

Just remember that shelf life is probably similar to in-service life, so you can't just "stock up" and keep the spares in a cupboard.

FWIW, I have several very old VAX systems (>12 years), some of which still have the original batteries, still working. Others have dead batteries, but I haven't bothered to change them because they're clustered and any clock errors will always be corrected soon after a reboot.

Re: 4105A/4106A battery life

Sunil_uk — Wed, 11 May 2005 04:22:20 GMT

Thank you for the reply.
I am monitoring mutliple remote system and recently it is so happened that due to some problem VMS crashed and while rebooting it stoped at time/date prompt. this I could see after going to the site, which slightly far away and it caused down time for the server.

These are prety old systems and I do not think that the battery been replaced for the last 6-7 years.

thank you

Re: 4105A/4106A battery life

Volker Halle — Wed, 11 May 2005 04:47:17 GMT

Sunil,

please also take into acount, that you need to do a SET TIME = "''F$TIME()'" on each OpenVMS VAX system ONCE each year between 1-JAN and 11-APR (will be automatically done on a shutdown) to correctly set the TOY clock and the date in the base image.

See section

4.1.1.3 Why does VAX need a SET TIME at least once a year?

in the OpenVMS FAQ:

http://h71000.www7.hp.com/faq/vmsfaq_004.html#faq_time

Missing this could be another reason for a prompt to set the time after a crash.

Volker.

Re: 4105A/4106A battery life

Volker Halle — Wed, 11 May 2005 05:02:06 GMT

Sunil,

and while further thinking about this:

- if the TOY batterie is really dead, wouldn't the BOOT settings also have been lost (BOOT, BFLG, HALT ) ?

- and you didn't loose power, only the system crashed - right ?!

So maybe your batteries are just fine, although you never know, without powering down the system ;-(

Volker.

Re: 4105A/4106A battery life

Jan van den Ende — Wed, 11 May 2005 05:33:50 GMT

Volker,

I am not so sure about that...

As far as I know, those values are stored in EPROM, and remain intact for quite some time without power.

But the clock has to be updated every clock-tick interval, and THAT needs power!!

I do remember (way back) several occasions where a Vax or VaxStation DID boot according to settings, but DID ask for date-time input, which seems to support this.

I _MAY_ be wrong here, but my gut feeling says...

Proost.

Have one on me.

jpe

Re: 4105A/4106A battery life

Sunil_uk — Thu, 12 May 2005 03:48:32 GMT

HI,

Is there any sysgen parameter which enables the system to ask date and time whenever it boots up

sunil

Re: 4105A/4106A battery life

Ian Miller. — Thu, 12 May 2005 04:01:44 GMT

if you set the SETTIME system parameter to 1
then VMS will ask for the datetime every time it boots.

Re: 4105A/4106A battery life

Volker Halle — Thu, 12 May 2005 04:47:08 GMT

... and there is TIMEPROMPTWAIT, which controls the behaviour of the system during boot, if the TOY clock does NOT contain a valid time.

Before jumping to conclusions about the TOY battery being dead, please check, whether the system may not have seen a SET TIME command since 1-JAN-2005.

Volker.