What does it mean that two ISPs are "peering" with each other?

Could the Internet work without Internet eXchange Points (IXPs)?

Your home network infrastructure consists of a wireless router/modem connected to the Internet over a (traditional land) phone line. Your and your mom's computers are connected to the Internet through this wireless router/modem. 

You observe that downloading Netflix movies over the Internet becomes significantly slower than usual every Saturday night. What are plausible reasons?

(Many answers may apply.)

On a 64 bits architecture, what does the following code print ?

  const char* s = "123456";
  printf("%zu\n", sizeof(s));

Note: "%zu" is indeed the correct way to print values of size_t type.

What does the following code excerpt print?

  int tab[] = { 2, 4, 6, 8, 10, 12 };
  putchar('1');
  int a = -1;
  int* p = tab + 2;
  while ((a = *p++) < 10) { printf("%d", a); }

Considering

 What happens if a system crashes while writing data without crash consistency mechanisms?

Which statement(s) is/are TRUE regarding the structure of two-level indexing?

In a three-level indexing system, the first level contains pointers to the second-level index blocks, which in turn point directly to data blocks.

Multi-level indexing in a file system is used to manage large files efficiently by breaking index structures into multiple levels.