67108864 bytes are also known as 64 MiB (Mebibyte).
Many softwares like PHP still identifies 64 MB as 64 MiB, this is an historically grown issue.

Nowaday we define 64 000 000 bytes as 64 MB (Megabyte, 64 * 1000 ^ 2)
and 67108864 bytes as 64 MiB (Mebibyte, 64 * 1024 ^ 2).

Failed to allocate memory - What is it trying to say?
Imagine the following written conversation, as recently occurred via SMS between me and a friend (edited for brevity):


  A: What are you going to do today?
  
  B:  I don't know.  Go shopping?


What is the meaning of the question mark in the reply?  Is person B asking a question of person A?  If so, why would person B expect person A to know the answer in this case? If not, why use the question mark?
