[Info-vax] The dangers of extended uptime. Was: Re: swap and page files

[Paul Sture]

In article <kc497f$s4p$1 at dont-email.me>,
 Stephen Hoffman <seaohveh at hoffmanlabs.invalid> wrote:

> On 2013-01-03 15:15:24 +0000, Paul Sture said:
> 
> > ...it's surprising what can come crawling out of the woodwork...
> 
> If you don't test or if you miss a test case, certainly.

One positive result of the conversation with my friend was that it 
prompted him to dig out test plans which were created but not executed 
due to other work taking priority...
 
> Apple just got bagged by a corner case in iOS date handling with their 
> Do Not Disturb function, and the details of that are still just 
> filtering out.
> 
> VMS was getting bagged by date handling for years, and it's still far 
> too messy for my preferences.  VMS date handling is still arguably 
> fundamentally broken, too. Unix got this one (more) right with UTC 
> everywhere, rather than localtime.  But I digress.

When I first learned that NTFS stores file dates as UTC I could 
immediately see the disadvantages of VMS clusters across time zones.  
However NTFS has its own problems:

<http://en.wikipedia.org/wiki/NTFS#Universal_time>

"As a result, especially shortly after one of the days on which local 
zone time changes, users may observe that some files have timestamps 
that are incorrect by one hour. Due to the differences in implementation 
of DST in different jurisdictions, this can result in a potential 
timestamp error of up to 4 hours in any given 12 months."

This has implications for anything using date based file comparisons 
such as rsync and the likes of Dropbox.  When I tested a Truecrypt disk 
image with Dropbox I noticed that Truecrypt leaves the container image 
date untouched when its contents are changed.  Dropbox noticed this when 
changes were made on more than one system and saved inconsistencies in 
separate files, but you need to be aware of this.

> There's reportedly a very evil PCSI bug floating around in an error 
> path, too — make sure your PCSI patches are current, or Very Bad Things 
> can happen.
> 
> I've chased critters in NEWUSER over the years.  If you're not current 
> there, please upgrade.
> 
> Bugs happen.
> 
> That's why we test, after all.
> 
> Long server uptimes are the antithesis of testing.

Yes, yes and yes.

-- 
Paul Sture