4.2: hardware Flashcards
processor
- part of the computer that processes data by executing programs
- manages the rest of the hardware
main memory
- memory that can be accessed directly by the processor.
- The main memory consists of memory locations that store instructions or data.
- 2 types of main memory: volatile memory and non-volatile memory
volatile memory
loses its contents when the power is removed
non-volatile memory
keeps its contents even without power
RAM
- volatile temporary memory that has adressible locations
- Each location can be accessed randomly, so any instruction or data can be placed in any location
ROM
- non-volatile (permanent memory)
- different from secondary memory
motherboard
- main printed circuit board (PCB) inside a computer
- connects all the components of the computer together.
- Similar to a human nervous system, a motherboard transmits signals between a computer’s components.
what does GPU stand for
graphics processing unit
graphics processing unit (GPU)
- processor designed specifically to render graphics.
- In the early days of computers, the CPU was responsible for this job. Now that graphics have become more advanced and require more computation, specialist processors have been designed to process graphics more efficiently and to take the burden off the CPU
Rendering
the process of converting image data into the graphics that you see on the screen
sound card
- component needed to output audio signals to devices such as headphones or speakers and to receive an audio input from devices such as microphones
characteristics of RAM
- It is volatile
- You can read and write to it
- It is quicker to access than secondary storage
- It has the largest capacity of all main memory
characteristics of ROM
- It is non-volatile
- It is written by the computer manufacturer
- Usually stores the BIOS
- Smaller capacity than RAM
purpose of RAM
Stores data and
instructions
during processing
purpose of ROM
Stores boot-up
instructions set by
the manufacturer
volatility of RAM
Volatile, data lost
without power
volatility of ROM
Non-volatile, data
remains after
power switched off
read/write of RAM
read and write
read/write of ROM
read only
capacity of RAM
usually several gigabytes
capacity of ROM
a few megabytes in size
Cache memory
- Designed to make access to frequently used data much faster
- There are three levels of cache used by the processor, each level has a different capacity and access speed. The closer the cache is to the CPU, the faster it can read and write data, but the less it can store
level 1 cache
usually a part of the processor itself. This cache has the lowest capacity, but the quickest access speed
level 2 cache
In some processors, the level two cache might be built into the processor along with level one.
Level two is slightly slower to read but has a higher capacity than level one
level 3 cache
the slowest at reading and writing, but it is still roughly twice as fast as RAM.
Registers
- small memory devices
- provide faster access than both the RAM and cache but are only able to hold a few bytes at most.
- split into two categories: general purpose and dedicated
general purpose registers
used to temporarily store values generated by instructions if they need to be used again in the next instruction
dedicated registers
serve a specific purpose in the Fetch-decode-execute cycle
virtual memory
a way a computer system can compensate for a shortage of RAM
why virtual memory is used
To reduce the likelihood of lags, freezing or crashing, computer systems allocate a portion of secondary storage as virtual memory
flash memory
- Flash memory is non-volatile and can be both written to and read from
- flash memory is used as both storage and main memory
system architecture
the structure of the internal components of a computer system
Neumann architecture
- occurss in modern computers
- involves: a processor; a memory unit, which stores both instructions and data; connections for input and output devices; and secondary storage for data
fetch-decode-execute cycle
describes how instructions are retrieved and processed in order to run a program