Why does it take a long time to create a copy of a file?

Question

C++ / C#

I create a copy of the wav file, which I pass as an argument to the program. And then I send byte by byte to stdout to a file ( wav > output).
A file of 9 megabytes is created noticeably ... very noticeably longer than just copying in the file manager.
What is the difference between the algorithms?

Answer 1

First, if you read and write byte by byte, then the number of system calls is equal to the number of bytes in the file, and each system call is a context switch. Secondly, if the work is carried out from the HDD, then the head rushes from place to place, and its positioning is a hell of a long operation. Thirdly, the file manager most likely does not read or write the file at all, but simply makes one system call, such as splice , and then DMA does the copying.