Architecture of the CPU Flashcards
What is a general purpose computer
A computer that is designed to carry out different tasks. A PC is an example of a general purpose computer.
What can we use a general purpose computer for
- Access the internet
- Browse the world wide web
- Use word processing 4. software
- gaming
- communication
- designing, building web pages
- storing and retrieving data
- play videos and music
What is data
Information, usually numbers and words and letters that are collected for usage and are examined for a task
What is an address
A location of data usually in a memory stick or a disk
What is the CPU
Central Processing Unit
It is the most important hardware component of a computer. Its job is to process the instructions from the main memory. It runs one simple instruction at a time.
Where does the CPU access instructions and data from
RAM (Main memory)
What are the two major components of a CPU
Control Unit
ALU (Arithmetic Logic Unit)
What was Von Neunam’s idea
To store program instructions and data in the same memory. Because of this, it is proven that program instructions and data used by programs are stored in the same memory
What is a register
A fast memory location in the CPU
What are the four registers in a CPU
Accumulator
Program Counter
MAR
MDR
What is the Accumulator’s function
Stores the arithmetic and logical results
What is the Program Counter’s function
To hold the address of the next instruction to be executed
What is the MAR (Memory Address Register) function
To hold the memory address of the current instruction and then the data it uses, so these are fetched from the memory
What is the MDR (Memory Data Register) function
To hold the actual instruction and then the data that has been fetched from the memory
What is the Control Unit function
It coordinates and controls all of the activities taking place within the CPU.
It decodes then executes instructions
It also directs timing and control of other CPU parts like a conductor of the orchestra
What is the ALU (Arithmetic Logic Unit) function
It is where arithmetic operations are calculated
It also carries out logical operations
What are the steps in the FETCH cycle
- The address of the instruction to be executed is copied from the Program Counter to the Memory Address Register.
- The Control Unit then decodes the instruction and decides if data has to be fetched
- If yes, the MAR holds the address of the data to be used in the instruction. The data is then fetched and copied to the Memory Data Register
- The MAR knows where to look for data in the RAM. The MDR keeps hold of that data until its ready to be used in the CPU
What are the 3 factors affecting a CPU’s performance
Clock speed
Processor Cores
Cache size
What is clock speed
Clock speed is the cycles per second measured in hertz (HZ). It is a measure of how quickly the CPU is adapted to its function
What are core processors
The number of cores is the number of duplicate processing units (cores) placed in one CPU. Depending on the number of cores, the amount of instructions is performed at the same time.
What is cache size
The cache size is the memory on CPU, faster than RAM but slower than registers
What happens if we have a faster clock speed
The faster the rate of instructions are processed
How many cycles per second in 1KHz, 1MHz and 1GHz
1Hz = 1 cycle per second
1KHz = 1000 cycles per second
1 MHz = 1000000 cycles per second
1GHz = 1000000000 cycles per second
What is a dual core processor
When there are 2 processors in the same integrated circuit linked. It has the potential to perform 2 instructions at the same time . It allows twice as many instructions to be executed
What are the ideal conditions of increasing the core processors
A quad core processor has 4 linked processors and can be up to four times faster than a single core processor But if a computer is running a single program, it isn’t any faster since the program is probably designed to only run on one core.
What are three cache levels
Level 1 cache = It is very fast but is small located on the CPU. Each core has its own level 1 cache
Level 2 cache = It is usually given to each core. It is very fast, but slower than level 1 cache
Level 3 cache = Slowest type of cache. Faster than RAM though
What are the effects of cache memory
- It takes less longer to retrieve an instruction from there than on RAM. 2. Cache is closer to the processor than RAM as well.
- Program instructions and data fetched are stored in cache in case they are later required
What are the advantages of cache memory
- In most systems, Level 1 cache is used 50% of the time, and level 2 is assessed 90% of the time. 2. Cache reduces the time that the CPU has to wait for instructions and data from RAM
What are the disadvantages of cache memory
A
1. High costs than rest of memory
2. Handy storage capacity
3. Temporarily stores data
4. Volatile (unsaved data)
5. Increased margin costs than RAM, increasing the cost of the overall system
What is an embedded system
A computer system built into other devices.
What are examples of an embedded system
Dishwashers
Microwaves
What are embedded systems frequently used for
They are used to control a device with single inputs. Without an embedded system, digital devices would be limited to using their single functions
What are advantages of embedded systems
- Compact size
- High speed
- High reliability
- Low power consumption
- High accuracy
What are disadvantages of embedded systems
- Hard maintenance
- No room for technological improvements
- Less power supply durability
- Hard to take backup of embedded files
- Difficult to update and upgrade
What is the difference between a general purpose computer and an embedded system
General purpose computers can run multiple applications, whereas embedded systems only run one application and are designed for one specific purpose
General purpose computers can be programmed, embedded systems cannot be programmed
Embedded systems have runtime constraint speeds, while general purpose computers require faster execution
