On Python ≥ 3.5, use pathlib.Path.mkdir: from pathlib import Path Path(“/my/directory”).mkdir(parents=True, exist_ok=True) For older versions of Python, I see two answers with good qualities, each with a small flaw, so I will give my take on it: Try os.path.exists, and consider os.makedirs for the creation. import os if not os.path.exists(directory): os.makedirs(directory) As noted in comments … Read more
The Ruby IO documentation is not 100% clear on how this buffering works, but this is what you can extract from the documentation: Ruby IO has its own internal buffer In addition to that the underlying operating system may or may not further buffer data. The relevant methods to look at: IO.flush: Flushes IO. I … Read more
Sleep() is implemented at the OS level. The processor doesn’t spin when a task/thread/process is sleeping. That particular thread is put on a pending queue (the thread isn’t ready to run) until the time has expired at which point the thread will be placed on the ready to run queue. In the meantime, other threads … Read more
What is the difference between “zero-copy networking” and “kernel bypass”? Are they two phrases meaning the same thing, or different? Is kernel bypass a technique used within “zero copy networking” and this is the relationship? TL;DR – They are different concepts, but it is quite likely that zero copy is supported within kernel bypass API/framework. … Read more
The really simplified answer is that the kernel runs in kernel space, and normal programs run in user space. User space is basically a form of sand-boxing — it restricts user programs so they can’t mess with memory (and other resources) owned by other programs or by the OS kernel. This limits (but usually doesn’t … Read more
A trap is an exception in a user process. It’s caused by division by zero or invalid memory access. It’s also the usual way to invoke a kernel routine (a system call) because those run with a higher priority than user code. Handling is synchronous (so the user code is suspended and continues afterwards). In … Read more
On x86 you would do the following (simplified): Have the bootloader load the n-th sector of the disk/floppy (wherever you’re booting from) into memory and execute it (i.e. load segment/offset and do retf). A better alternative is to search the filesystem for a certain filename (e.g. KERNEL.BIN) — but you’d need to know the file … Read more
When python is executed, it creates sys.argv for you. The values in that list are based on the arguments passed to it by the operating system, but it leaves off the sys.executable value from that list. In other words, when Python is invoked, it sets sys.argv to everything but it’s own executable. When you invoke … Read more
Regarding cross-platform: your best bet is probably to write platform-specific code, and then import it conditionally. e.g. import sys if sys.platform == ‘win32’: import win32_sysinfo as sysinfo elif sys.platform == ‘darwin’: import mac_sysinfo as sysinfo elif ‘linux’ in sys.platform: import linux_sysinfo as sysinfo #etc print ‘Memory available:’, sysinfo.memory_available() For specific resources, as Anthony points out … Read more
As wikipedia knows in its Context switch article, “context switch is the process of storing and restoring the state (context) of a process so that execution can be resumed from the same point at a later time.“. I’ll assume context switch between two processes of the same OS, not the user/kernel mode transition (syscall) which … Read more