hardware Flashcards
A computer in which the processing instructions are stored in memory with the data is called a
Stored-program computer or von Neumann architecture computer
In von Neumann architecture computer:
The hardware device that does the processing is called the central processing unit (CPU).
* The storage is called main memory/random access memory (RAM). This is a temporary store for data and instructions (programs).
* Each memory location has unique memory address.
What happens when writing
When the CPU saves data into memory it is called writing
What happens when reading
when the CPU retrieves the data stored at a given address
what is a memory address
a number that uniquely identifies a storage/memory location.
what is a bus
a group of connecting wires (parallel wires). CPU and main memory are connected to each other, and to the input and output (I/O) devices by a bus
What does the CPU use the bus do
to tell the memory what data to save and where in the memory to save it. (i.e., when the CPU sends data to memory to be stored at a given address)
Input devices
keyboard, mouse, and touch screen
output devices
Monitor, Speaker, and touch screen
what is RAM
Random Access Memory
A temporary store that the CPU uses for currently running/using data, programs (instructions) and the part of the operating system (OS) currently being used.
RAM is typically measured in giga bytes (GB).
RAM is a volatile memory. Contents are erased when the power is turned off.
what is ROM
Read Only Memory
Non-volatile memory. Contents are no lost when the power is turned off.
ROM memory cannot be altered.
Programs permanently stored in ROM are known as firmware.
These programs are small, provided by the manufacturers and carry out specific task such as:
- Initializing hardware components
- Starting the operating system when the computer is switched on.
e.g.
BIOS – Basic Input/Output system or
UEFI – Unified Extensible Firmware Interface – this is now the standard firmware used in desktop computers.
What is cache memory
Cache memory is a memory used to make up for the difference in speed between two internal components.
This is kind of primary memory.
This is a small amount of fast, expensive memory that is used between two devices that communicate at different speeds, most often the CPU and RAM.
In the CPU cache, frequently used code or data is loaded in chunks from the slower RAM into the cache.
The CPU access the cache memory at its own, faster speed.
This means the CPU is not slowed down by having to wait data from the RAM.
What is cache miss
when the data requested for processing by a component or application is not found in the cache memory and the CPU has to wait for the cache to reload with the correct data.
CPU technology developed much faster than RAM. RAM in newer computers no longer keep up with the demands of the CPU. This caused a bottleneck (where something is working at a full capacity and cannot handle further demand) that limited the performance of computers.
Cache memory was introduced to solve this problem
What is a microprocessor
the central unit that executes and manages the instructions passes to it.
What is buffer
temporary storage created for data transmitted from one part of the system to another which functions as a queue
Most I/O devices have memory between themselves and the main system because they communicate at different speeds. This is called a buffer.
e.g. disk buffer, printer buffer or frame buffer for graphics.
Data is transferred at high speed between processor and this memory. The CPU can then continue with other tasks while the I/O device takes data from its buffer at a slower rate.
