UTC=no in /etc/default/rcS on a Fresh Install 14.04. Why?

dual-boot 14.04 system-installation time

5,654

If you install Ubuntu on a clean disk with no other OS, UTC=yes is used as default. In your situation, you have Windows aside Ubuntu. So in the installation Ubuntu detected Windows and set UTC=no. Although your Ubuntu is clean, the disk is not clean.

5,654

Jon Hanna

Growing up, I was always sure I wanted to either become a developer or a writer. Finally, I made my choice. I would be a writer. Then I got a job as a developer by a fluke and that was that. I still write a bit. If I'd ended up being a writer, I'd probably still hack a bit. Indeed I still hack a bit, in that there's no better way to relax after a hard day's programming than to kick back and do a bit of programming. Right now my favourite off-the-clock project is contributing to CoreFX. That would seem to be the main reason I was made a Microsoft MVP in 2016 and 2017, though I think that I've a few answers on SO helped a bit. 1FBfQX9Y6QgDd9SWngpQ2PgAfh7FmMuFmy Favourite Charities: Abortion Support Network Dublin Rape Crisis Centre Abortion Rights Campaign BeLonG To

Updated on September 18, 2022

Comments

Jon Hanna over 1 year

I recently installed 14.04, and decided to do so as a fresh install.

I wiped the only Ubuntu installation on the system, left a Windows 7 installation on, and installed over mdadm (once with /boot on mdadm and later with it not on mdadm as that saves a few other headaches. I'm pretty sure what I'm describing happened in both cases).

Everything from previous Ubuntu installations were completely wiped by manual formatting of the relevant partitions.

I'm in a time-zone currently on Irish Summer Time (UTC+01:00). Windows started jumping the time an hour ahead.

Now, I might expect a default Windows installation to jump the time an hour back, thinking the UTC bios time was the local time, but this was an hour ahead and I had RealTimeIsUniversal set in the registry to get some saner behaviour out of Windows.

After some puzzling over this, I realised that in /etc/default/rcS there was the line UTC=no to set Ubuntu onto local time rather than the normal UTC=yes.

This is a well-known setting for people who normally only use Windows as the illogical choice of local time (not unambiguous) means less change for them than fixing Windows in a way that MS don't support, but I certainly didn't set it.

This was easily fixed, but as I don't know what broke it, I don't know that it won't be broken again.

Is there anything that sets UTC=no upon use or installation, and if so can that be blocked?
Jon Hanna about 10 years

Well, that's pretty uselss if it's true. Does the same thing happen if there's a mix of Win and Linux?
snowhawkyrf about 10 years

@JonHanna I think it's a compromise. As Win and Linux have different time switching, you have to choose one as default.
Jon Hanna about 10 years

which I had done. It decided to do what most linuxes do not do, and I can't see that choice documented anywhere.