The poll() system call waits for an event on a file descriptor. Your program stops running and the kernel takes over, allowing other "stuff" to run until the kernel itself sees the event, then it un-stalls your program and lets it run.
As I said, I don't call that real interrupts but apparently Linux people do. :~
Your program stops running and the kernel takes over,
Surely a basic principle of any OS worth its salt is insulating the hardware from the user and vice-versa.
The latest disappointment is that the Pi can't do real interrupts.QuoteThe poll() system call waits for an event on a file descriptor. Your program stops running and the kernel takes over, allowing other "stuff" to run until the kernel itself sees the event, then it un-stalls your program and lets it run.in this thread:-http://www.raspberrypi.org/phpBB3/viewtopic.php?f=33&t=10377As I said, I don't call that real interrupts but apparently Linux people do. :~
I suppose my question is: If this is a small Unix box, running Linux, why bother putting little pins down the side to connect hardware to? Using your model, Jack, we should be connecting things via USB, with an appropriate device driver, and use high-level abstraction to hide the implementation details from the program.
IMHO it say that it IS interrupt, but it also put your thread/process in wait state and go on processing other process/thread
by pluggy » Thu Jul 26, 2012 10:31 amI complained about RS a while back and had the thread deleted for my trouble. They've had my money for a month with a delivery date in October. Ring up and they fob you off with "you have to email the Raspberry Pi team", needless to say I'm still waiting for a reply 3 weeks later. No doubt this thread will be going the way of the Dodo bird as well. Their justification being if you read the sticky at the top it says:It is not the place to air general moans or complaints about RS or Farnell (or anyone else for that matter)Since its pretty obvious RS don't give a ****, the foundations unholy alliance with said company is next in line. Already had one warning, no doubt I'll be down the road after this.If they can't fulfil the order in a reasonable time frame, they have no justification whatever for taking your money when you place the order.Dear Mod, I didn't start this thread, another disgruntled RS customer did, Since the foundation formed the alliance with them, the foundation have a responsibility. Of course, you can take a leaf out of RS's book and hide behind your terms and conditions..........
All rumours to the effect that the Ras Pi mods are heavy handed is totally unfounded
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