1.1 Systems Architecture Flashcards
What actions occur at each stage of the fetch-execute cycle?
1)The CPU fetches the instructions one at a time from the main memory into the registers.
2)One register is the program counter (pc). The pc holds the memory address of the next instruction to be fetched from main memory.
3)The CPU decodes the instruction.
4)The CPU executes the instruction.
Repeat until there are no more instructions.
ALU
The ALU has two main functions: It performs arithmetic and logical operations (decisions). The ALU is where calculations are done and where decisions are made. It acts as a gateway between primary memory and secondary storage .
CU
The control unit of the central processing unit regulates and integrates the operations of the computer. It selects and retrieves instructions from the main memory in proper sequence and interprets them so as to activate the other functional elements of the system at the appropriate moment
Cache
A cache’s primary purpose is to increase data retrieval performance by reducing the need to access the underlying slower storage layer. Trading off capacity for speed, a cache typically stores a subset of data transiently, in contrast to databases whose data is usually complete and durable.
Registers
Registers are small amounts of high-speed memory contained within the CPU. They are used by the processor to store small amounts of data that are needed during processing, such as: the address of the next instruction to be executed. the current instruction being decoded.
MAR (Memory Address Register)
Holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred.
MDR (Memory Data Register)
MDR is the register in a computer’s CPU that stores the data being transferred to and from the immediate access storage. It contains a copy of the value in the memory location specified by the memory address register.
Program Counter
A program counter is a register in a computer processor that contains the address (location) of the instruction being executed at the current time. As each instruction gets fetched, the program counter increases its stored value by 1.
What is the difference between storing data and am address?
Data is the term used to describe information, and address is the term used to describe the location of an item of information. It all sounds very simple and obvious; but it is anything but simple.
Clock speed
The clock speed measures the number of cycles your CPU executes per second, measured in GHz. A “cycle” is technically a pulse synchronized by an internal oscillator, but for our purposes, they’re a basic unit that helps understand a CPU’s speed.
Cache size
The “size” of the cache is the amount of main memory data it can hold. This size can be calculated as the number of bytes stored in each data block times the number of blocks stored in the cache.
Number of cores
The number of cores indicates the number of processing units in a computer. Nowadays, computers can contain two (dual-core), four (quad-core), six, twelve, or even more cores.
Effects of changing the characteristics
Improves performance and speed
Embedded systems
An embedded system is a combination of computer hardware and software designed for a specific function. Embedded systems may also function within a larger system. The systems can be programmable or have a fixed functionality.
Characteristics of an embedded system
Sophisticated Functionality.
Real-Time Operation.
Low Manufacturing Cost.
Processor and Memory.
Tight Design Constraint.
Based on Performance and Functional Requirements.
Based on the Performance of the Microcontroller.
