Part1 Block3 - Main Memory Flashcards
Main memory is where the instructions, and the data they act on, are loaded from when a program is executed.
What happens to its contents when the power is switched off?
What is the name for this type of memory?
v__________ m__________
its contents are lost
volatile memory
Each byte in main memory is numbered in sequence, so that it has a unique memory address.
Historically, there weren’t address and tape had to be run all the way through to find something.
What Acronym for Main Memory has emerged from this difference and why?
RAM - Main Memory often referred to as RAM, or Random Access memory,
as the address means that we can easily access something randomly, instead of having to go through it in sequence.
What is an advantage of each byte having its own, unique address?
Much faster to access.
When measuring the amount of main memory (or cache memory) in bytes, the prefixes kilo, mega, giga, tera, etc. are based on binary powers of _____________
2
You have learned that main memory is volatile – when the power is turned off, the content of the memory is lost.
If this is the case, how does the computer get the first instructions to execute immediately after the computer is turned on?
It uses the ROM Memory
There is a separate area of memory called r____-______ memory (ROM).
The contents of ROM are not lost when the power is switched off, so this kind of memory is called p___________ memory.
read-only memory
persistent memory
An important function of ROM is to store a program, called a b______ program, which is automatically executed when the computer is first switched on, or ‘booted up’.
This small program will typically do some hardware housekeeping, such as r_______ a t________ of m________. It will then load larger programs, such as the o___________ s________, into main memory.
a boot program
running a test of memory
operating system
Locations in main memory are c___________ (that is, they follow on from each other) and are sequentially numbered, so that each one has a unique memory address.
The first memory location to be allocated is always given an address of _____
Contiguous
0
Most computers are sold with at least 4 _ _ _ of main memory.
GiB
Write 4 GiB in binary scientific notation.
4 x 2^30
Why do humans usually represent memory addresses in hexadecimal?
It’s more compact. Smaller to write.
Sometimes hex values are prefixed by ____ or appended by ______ to show that they are in the hexadecimal number system.
E.g. 0x4ee2 or B5A2 h.
0x
h
It is not only memory addresses that are written in hex; many large binary quantities in computing are represented in this way.
For example, o________ s__________ e________ are often designated in hex
operating system errors
