Film-Tech Forum ARCHIVE: GDC SX-2000: Time Setting??

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Posted by Jim Cassedy (Member # 4115) on 07-24-2015, 02:49 PM:

I noticed the local clocks in two GDC SX-2000 servers at one theater are
off quite a bit. One of them is almost 9min fast (compared to the actual
time,and the clock in the TMS, which is set correctly.

Forgetting about NTP for the moment, how do you set the local clocks in
each server? I went into the ADMIN screen, and all I could see was a way
to set your time zone. How do you set the time? Is it in one of the menus,
or do I have to get into BIOS when it's booting up and do it there?

Posted by Steve Guttag (Member # 268) on 07-24-2015, 03:17 PM:

If the server is on version 8 (DCI compliant) then you have very limited resources. But logging in via the admin panel and going to DCI Compliance...you can enter in an RTC offset so long as it is within range. 9 minutes is going to be out of range.

Really, you do need an NTP to keep these things on time.

Now if you are on version 7.x then it is the BIOS clock but they do password protect the BIOS. In version 8, the BIOS clock isn't the secure clock anymore.

The show clock in the upper-left can be a bit deceptive and is never really correct (typically off by 5-15 seconds). To see the actual time it thinks it is...look either in the Scheduler (will show down the seconds) or in the Control Panel>System Monitor.

Posted by Dave Macaulay (Member # 813) on 07-24-2015, 09:06 PM:

The TMS should run an NTP server so that all the screen servers will at least start at the time the TMS thinks it is. The TMS should ideally be getting time from an outside NTP server. For VPF clients their NOC will have an NTP server the TMS can sync to: NOCs want the screen servers to then sync to their TMS to reduce bandwidth required at their NTP server.

Posted by Steve Guttag (Member # 268) on 07-24-2015, 09:58 PM:

Most NTP servers have "flooding" protection. If think about everything within a cinema that could be asking for the time...TMS, screen servers, projectors, automations immediately come to mind. If all of those things are asking for the time and all at their own rate, it is conceivable that many requests could happen all at about the same time to an outside NTP server...they will all appear to be from the same IP address due to how the Ethernet works so you could trigger a flooding protection. Then multiply that by every location wanting time that may be calling a particular NTP...it would be huge and inefficient.

As such, the TMS should be the NTP source for the complex...Thus the outside source would only see the request about once every 8-15 minutes and never trigger a flooding protection. Another advantage to using a TMS is often they can use naming rather than just the IP so things like the ntp.pool can become an NTP source for the complex even if the individual devices can only work with IP addresses.

Posted by Mark Gulbrandsen (Member # 72) on 08-06-2015, 12:30 PM:

if you are running 8.X GDC can remote in and set the proper time. This assuming there is a way for them to get in. Otherwise you'll have no choice but to NTP it. An NTP will actually pull the clock further that you are allowed to in DCI Compliance in the admin panel. I have theaters that loose internet connectivity and the servers drift... I have seen them NTP correct up to as much as 20 minutes.

Mark

Posted by Carsten Kurz (Member # 5396) on 08-06-2015, 01:55 PM:

Which is not DCI compliant. How do they know they can trust the NTP?

- Carsten

Posted by Harold Hallikainen (Member # 5405) on 08-06-2015, 03:09 PM:

Echoing Carsten's question, I'm surprised that you can set the secure clock with NTP. It seems like it would be easy enough to set up an NTP server with any time you'd like.

For some interesting reading on NTP request floods, see http://pages.cs.wisc.edu/~plonka/netgear-sntp/ .

Harold

Posted by Mark Gulbrandsen (Member # 72) on 08-06-2015, 05:09 PM:

There are three ways to set a server running 8.X..

1. By using the DCI setting in the admin panel, which only allows about a 8 min. per year change.

Hook the servers to an NTP Source. In my installations it is always a TMS two screens or larger. Single screens have a booth computer. I have seen them pull 20 minutes. I never had one more then this amount off, so I can't say what will happen beyond this. But should it not there is always step 3.

3. Have GDC remote in and make the adjustment for you. They are allowed by DCI to do this and the method has been approved by DCI.

It is of course very easy to verify that NTP is working as all the servers in a site will be synced up within the limits that the screen refresh that service. You can also compare the time on your phone or the *internet time* on your TMS or booth computer to verify it.

Except at sites we loose internet connectivity or if a wide area network issue develops there are basically zero time keeping issues.

If you can simulate NTP, then yes. You could likely set it to some other time just as you can do with the DCI setting in the admin panel. I just can't say how far other than 20 minutes it is able to drag it one way or the other.

I have had no issues with 2000AR's drifting but I only ever installed two of these before I switched to using the SX-3000. SX-3000 also is very stable time wise. I have two that run free standing over in Wyoming and there has been no real drift in over two years.

Mark

Posted by Steve Guttag (Member # 268) on 08-06-2015, 06:54 PM:

The fixed time allotment should be just that, regardless of source. I have not problem with NTP setting the secure time but it should be limited to the +/- 6 minutes or so as mandated by DCI.

Posted by Mark Gulbrandsen (Member # 72) on 08-09-2015, 10:20 AM:

So if it goes out more than the allowed DCI amount the manufacturer can still go in remotely to fix it. And that is approved by DCI by the way. NTP is a better way IMHO.