3 ms·

I also have a DNS logger and I found that iOS makes a lot of requests to time-ios.apple.com. That one isn't really alarming, though.

TazeTSchnitzel 9y ago
Hmm. Can’t it just rely on the mobile network? I suppose Apple trust their own time servers more.
- toast0 9y ago
  Some mobile networks do a decent job of providing the time, some do a poor job, and some don't provide time at all (saw this when I was overseas). I would accept the time from the mobile network as a starting point, but prefer to get it from IP networks I trust, or from global positioning.
Spivak 9y ago
Is is if your you want your alarms to sound on time.
freehunter 9y ago
I'm still amazed that computers are so terrible at telling reliable time without connecting to a network constantly. I've seen computers with a fully-functional CMOS battery lose 5 minutes a month without a network connection. Mind blowing.
- LeoPanthera 9y ago
  That is surprising, so surprising that I have to assume the computer in question was running some kind of misbehaving ntpd that was skewing the clock. A good quality quartz crystal is accurate to about 15 seconds a month. Even the cheap ones can manage 30 seconds a month.
  - freehunter 9y ago
    My car loses about 3 minutes per month, and it has no ability to query NTP. Oddly enough my SUV gains about a minute per month.
- baudehlo 9y ago
  Knowing why and how this happens should be a basic course in computer science classes.
  - tomjakubowski 9y ago
    I would say its place is more in a computer engineering or an "applied computer science" discipline. Similarly, a chemistry student doesn't especially need to learn about how to plan a safe and cost-effective end industrial synthesis process, which would fall squarely in the domain of chemical engineering.
- morecoffee 9y ago
  Why would it be surprising? Manufacturers optimize for cost. The clock in your computer is the cheapest one they can find.
- mitchty 9y ago
  For a mobile phone it might make sense to check more often as they tend to either move timezones more often, or be powered off and then back on again.
- someguydave 9y ago
  It turns out that if you really want a device that can keep accurate time over a long period you must pay a significant amount of money. You would need a temperature compensated crystal (TCXO) or ovenized crystal oscillator (OCXO). Both of these would cost tens to hundreds of dollars, which is orders of magnitude more than hardware makers are willing to spend. Not to mention these kinds of accurate oscillators tend to be power hungry.
- natch 9y ago
  But that is missing the main point of the network time checks. Even if computers were perfect at telling time you still need to check network time for security reasons, especially if local users can change the device time. There are crypto attacks that rely on changing the time, and checking that the time matches another somewhat reliable source helps make those attacks harder to pull off.

TazeTSchnitzel 9y ago

Hmm. Can’t it just rely on the mobile network? I suppose Apple trust their own time servers more.

toast0 9y ago
Some mobile networks do a decent job of providing the time, some do a poor job, and some don't provide time at all (saw this when I was overseas). I would accept the time from the mobile network as a starting point, but prefer to get it from IP networks I trust, or from global positioning.

Spivak 9y ago

Is is if your you want your alarms to sound on time.

freehunter 9y ago

I'm still amazed that computers are so terrible at telling reliable time without connecting to a network constantly. I've seen computers with a fully-functional CMOS battery lose 5 minutes a month without a network connection. Mind blowing.

LeoPanthera 9y ago
That is surprising, so surprising that I have to assume the computer in question was running some kind of misbehaving ntpd that was skewing the clock. A good quality quartz crystal is accurate to about 15 seconds a month. Even the cheap ones can manage 30 seconds a month.
- freehunter 9y ago
  My car loses about 3 minutes per month, and it has no ability to query NTP. Oddly enough my SUV gains about a minute per month.
baudehlo 9y ago
Knowing why and how this happens should be a basic course in computer science classes.
- tomjakubowski 9y ago
  I would say its place is more in a computer engineering or an "applied computer science" discipline. Similarly, a chemistry student doesn't especially need to learn about how to plan a safe and cost-effective end industrial synthesis process, which would fall squarely in the domain of chemical engineering.
morecoffee 9y ago
Why would it be surprising? Manufacturers optimize for cost. The clock in your computer is the cheapest one they can find.
mitchty 9y ago
For a mobile phone it might make sense to check more often as they tend to either move timezones more often, or be powered off and then back on again.
someguydave 9y ago
It turns out that if you really want a device that can keep accurate time over a long period you must pay a significant amount of money. You would need a temperature compensated crystal (TCXO) or ovenized crystal oscillator (OCXO). Both of these would cost tens to hundreds of dollars, which is orders of magnitude more than hardware makers are willing to spend. Not to mention these kinds of accurate oscillators tend to be power hungry.
natch 9y ago
But that is missing the main point of the network time checks. Even if computers were perfect at telling time you still need to check network time for security reasons, especially if local users can change the device time. There are crypto attacks that rely on changing the time, and checking that the time matches another somewhat reliable source helps make those attacks harder to pull off.