Software or Hardware

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BongoBern
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Joined: Mon Apr 19, 2010 4:17 pm

Software or Hardware

Post by BongoBern » Tue Apr 27, 2010 6:17 pm

Is all the "fun" happening overnight (April 26th/27th) software glitches, hardware glitches, combinations? It seems like there is a fair bit of programming (as you'd expect) going on, "on the fly." Is that what most of this testing before 7TeV per beam is all about; the software/hardware handshakes and cooperation? All those alrams would make me twitchy! :crazy:

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mrgumby
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Location: New Zealand

Re: Software or Hardware

Post by mrgumby » Wed Apr 28, 2010 6:15 am

I think that basically they are learning how to drive the LHC at low speed before they take it out on the expressway....

;)

Kasuha
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Re: Software or Hardware

Post by Kasuha » Wed Apr 28, 2010 8:18 am

Running such a big hardware is not easy. No piece of electronics works flawlessly for eternity and there's such an awful lot of it in LHC there's no wonder something goes wrong on daily basis. That's why all LHC systems are backed up or redundant, without it LHC wouldn't be able to run at all.
Software isn't perfect either. There's a lot of software used in LHC, every piece of hardware uses slightly different control system and although a lot of time and effort was spent on fixing all problems and making them work together there are still minor bugs and problems left to be discovered and fixed over time.
For a project of such size, these factors are no surprise - approximate times between hardware/software failures and times needed for fixing are in fact included in their plans. Nobody can predict what exactly will go wrong but it can be estimated how much and how often on average.

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Tau
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Re: Software or Hardware

Post by Tau » Wed Apr 28, 2010 8:21 am

The LHC has so many controls (I estimate about a million) that have to be set in exactly the right way in exactly the right order. They do this in three steps:
  • First they figure out how to set everything.
  • Then they try this out by hand.
  • Than they automate the procedure.
This has happened for many, many steps in the process. I've seen them doing this with precycling ("combo"), injection, setting the beam orbit ("golden orbit"), setting collimators ("stable beams"), tuning, ramping, squeezing. And soon squeezed stable beams will be something that requires a single button press, and they go on to the next problem. This even includes handling failure of equipment (for example, a quench in a steering magnet is not an issue nowadays: they just use a few other ones and go on).

So, at first you get the impression that everything went wrong, then you get the impression that they appear to understand the process, and finally there seems to be no problem at all!
- Tau

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