A program 9kb in size takes up 2mb in RAM?

Question

Why?

This is just an example but when you open a program it gets stored in RAM, but why would it need so much more than what it takes up on the hard drive?

Answer 1

Just because a program takes up little space on the hard drive does not mean it uses no memory. Graphics programs need a large buffer, for example. It may also need large amount of memory to buffer disk writes and reads, and other buffering operations. Some programs are also self-expanding, as it decompresses itself into memory upon loading, reducing actual footprint. There are lots of possibilities.

Think of that program as computing equivalent of Aero Bed (tm). :) A full-sized bed that can be stored in size of a knapsack, and expands to full size in minutes. :)

Answer 2

i suppose you're talking of an .exe file that has a size of 9kb on the disk - right?

you now should know something about programming techniques. in C++ programming the .exe file only consist of the main program, this is in most cases a negligible part (in size) of the entire program. the majority of the full program consist of so-called .dll files (dll stands for Dynamic Link Library). when you start a program (the .exe file) all belonging libraries will also be loaded in the memory, what explains the "explosion" in size.

Answer 3

Once it loads in memory and starts running, it can request more memory, presumably to handle the tasks for which it is written.

Also, there is a minimum memory allocation, the size of one memory 'page'. I forget what that is for any given computer. It depends on the OS and the CPU.

Answer 4

Because much more is being loaded, there is overheard beyond the program space, Graphics, and a few other things as well.