What is the difference between pages and blocks? A block is the smallest unit of data that an operating system can either write to a file or read from a file. What exactly is a page? Pages are used by some operating systems instead of blocks. A page is basically a virtual block. And, pages … Read more
Simple solution: Open Xcode. Select the “Window” menu. Select “Devices and Simulators”. Select Simulators tab. Click on the “+” icon at the left bottom. Choose the desired device & preferred iOS. Click “Create”. Enjoy :).
Going to sleep until the scheduler wakes you is the normal/prefered thing to do. Spinning (the alternative way to wait, without sleeping) is less usual and has the following effects: Keeps the CPU busy, and prevents other threads from using the CPU (until/unless the spinning thread finishes its timeslice and is prempted) Can stop spinning … Read more
Short Answer: They are different things. A system call is call by software running on the OS to services provided by the OS. An interrupt is usually external hardware component notifying the CPU/Microprocessor about an event that needs handling in software (usually a driver). I say usually external, because some interrupts can be raised by … Read more
The memory barriers present on the x86 architecture – but this is true in general – not only guarantee that all the previous1 loads, or stores, are completed before any subsequent load or store is executed – they also guarantee that the stores have became globally visible. By globally visible it is meant that other … Read more
A blocking system call is one that must wait until the action can be completed. read() would be a good example – if no input is ready, it’ll sit there and wait until some is (provided you haven’t set it to non-blocking, of course, in which case it wouldn’t be a blocking system call). Obviously, … Read more
load-time linking is when symbols in the library, referenced by the executable (or another library) are handled when the executable/library is loaded into memory, by the operating system. Run-time linking is when you use an API provided by the OS or through a library to load a DLL or DSO when you need it, and … Read more
I was having this issue on OS X too. It turned out gliptak was right, but I’ve some more detail to add. We’re both attempting to configure a virtual directory for a folder under a user’s home folder; I think this is why we’re having the problem. In my case, I had the following setup: … Read more
top shows CPU utilization for running processes while load average shows (since 1993) number of running processes plus number of processes in the uninterruptible state. Processes waiting for work do not consume CPU. As a result top CPU utilization is less that 7/8 * 100%. Source: http://www.brendangregg.com/blog/2017-08-08/linux-load-averages.html
No, in all practical operating systems, when a program exits, all its resources are reclaimed by the OS. Memory leaks become a more serious issue in programs that might continue running for an extended time and/or functions that may be called often from the same program.