What does it mean by buffer?

Question

I see the word \"BUFFER\" everywhere, but I am unable to grasp what it exactly is.

1. Would anybody please explain what is buffer in laym

Answer 1

A buffer is simply a chunk of memory used to hold data. In the most general sense, it's usually a single blob of memory that's loaded in one operation, and then emptied in one or more, Perchik's "candy bowl" example. In a C program, for example, you might have:

#define BUFSIZE 1024
char buffer[BUFSIZE];
size_t len = ;

// ... later
while((len=read(STDIN, &buffer, BUFSIZE)) > 0)
    write(STDOUT, buffer, len);

... which is a minimal version of cp(1). Here, the buffer array is used to store the data read by read(2) until it's written; then the buffer is re-used.

There are more complicated buffer schemes used, for example a circular buffer, where some finite number of buffers are used, one after the next; once the buffers are all full, the index "wraps around" so that the first one is re-used.