Re: [PATCH] rtc: Add an option to invalidate dates in 2038

[Posted February 24, 2016 by corbet]

From:		One Thousand Gnomes <gnomes-AT-lxorguk.ukuu.org.uk>
To:		Alexandre Belloni <alexandre.belloni-AT-free-electrons.com>
Subject:		Re: [PATCH] rtc: Add an option to invalidate dates in 2038
Date:		Sun, 21 Feb 2016 12:40:20 +0000
Message-ID:		<20160221124020.49f39207@lxorguk.ukuu.org.uk>
Cc:		Arnd Bergmann <arnd-AT-arndb.de>, rtc-linux-AT-googlegroups.com, Alessandro Zummo <a.zummo-AT-towertech.it>, Willy Tarreau <w-AT-1wt.eu>, linux-kernel-AT-vger.kernel.org
Archive‑link:		Article

> It doesn't change anything for 64-bit systems, I've excluded them by
> using "depends on !64BIT". Right now, it doesn't change anything for
> 32-bit systems because either way, they will fail in 2038.

Which realistically won't actually matter because in 22 years time nobody
will be able to find a 32bit system in common use. If you look at x86
platforms today a Pentium Pro is already a collectors item. All of todays
locked down half-maintained embedded and phone devices will be at best
the digital equivalent of toxic waste if connected to anything.

> Won't we have to recompile every application to support 64-bit time on
> 32-bit system anyway? That will be a good time to remove that option.

How will you know when everyone has ? There's no "autodetect which
distribution I am running" feature.

> If the distribution don't recompile to support a 64-bit time, then the
> 32-bit systems will break in 2038 anyway and they will absolutely
> require my patch or something along those lines to still boot using
> systemd.

I disagree. Systemd has a serious robustness bug. Patch systemd to handle
timerd going off early and to take appropriate recovery action.

If you fix the systemd bug you'll also deal with a load of other weird
cornercases like 32bit guests on a 64bit host that accidentally ended up
post 2038, and every other freaky rtc failure.

Alan

to post comments

32 bit systems becoming obsolete

Posted Feb 25, 2016 11:50 UTC (Thu) by epa (subscriber, #39769) [Link] (2 responses)

If Alan is right, then by a similar principle nobody should be able to find a 16-bit or 8-bit system in common use today.

32 bit systems becoming obsolete

Posted Feb 25, 2016 12:13 UTC (Thu) by juliank (guest, #45896) [Link] (1 responses)

And that's somewhat true.

32 bit systems becoming obsolete

Posted Feb 25, 2016 16:41 UTC (Thu) by khim (subscriber, #9252) [Link]

Have you ever had an Arduino word?

Sure, 8bit/16bit personal computers are collectors items (even so: three are lots of these around), but embedded systems still use 4bit CPUs!

Sure, they don't use Linux - but that's because Linux never supported them!

Internet of Things?

Posted Feb 25, 2016 18:42 UTC (Thu) by david.a.wheeler (subscriber, #72896) [Link]

We will see a <i>lot</i> more devices over the years with embedded computers, and there will be an incentive to make them as (relatively) cheap as possible. I have no idea if 32-bit embedded devices will be popular then - but it's entirely possible. 8-bit and 16-bit devices are absolutely still present today in embedded systems.

Re: [PATCH] rtc: Add an option to invalidate dates in 2038

Posted Feb 26, 2016 19:57 UTC (Fri) by Tov (subscriber, #61080) [Link]

...in 22 years time nobody will be able to find a 32bit system in common use.

This is going to be Allan's "640K ought to be enough" quote :-)

Re: [PATCH] rtc: Add an option to invalidate dates in 2038

Posted Feb 27, 2016 6:00 UTC (Sat) by dvdeug (subscriber, #10998) [Link]

Surely most embedded cases don't need more than 2GB of memory or fast support for 64-bit integers. No matter how cheap 64-bit systems become, it's going to be cheaper to just go 32-bit if you don't need more than that.