1.1 - System architecture

• Input is the data that is entered into the computer system, such as text, numbers, graphics, and audio.
• Output is the data that is sent to the user, such as a text file or a graphic image.
• Central Processing Unit (CPU) is responsible for the processing of instructions and data.
• The stored-program computer is a computer that has a program stored in a memory chip and is run by a series of instructions.
• Registers are small amounts of memory that can be used to store data.
• Program Counter is the address of the next instruction to be executed by the CPU.
• Memory Address Regisiter (MAR) is a register that holds the address of the memory location to be accessed.
• Memory Data Register (MDR) - holds the data that is to be transferred to or from the memory
• Accumulator holds the result of an instruction before it is transferred to memory.
• Control Unit is responsible for the execution of the program and the control of the CPU.
• Arithmetic Logic Unit is the part of the CPU that performs arithmetic and logic operations.
• Fetch causes the next instruction any data involved to be fetched from main memory.
• Decode is when the instruction is decoded.
• Execute is when the instruction is executed to the rest of the components in the CPU.
• Factors that affect the CPU performance is the clock speed, processor cores and cache.
• Clock speed is the amount of instructions per second measured in Hertz (Hz).
• Number of core is the number of duplicate processing units placed in one CPU.
• Cache size is the memory on the CPU that is faster than RAM but slower than registers.
• Level 1 cache is extremely fast but small.
• Level 2 cache is very fast however still slower than level 1 cache.
• Level 3 cache is the slowest type of cache but is still faster than RAM.
• Increasing processor clock speed would run more FE cycles per second, faster response, smoother actions and is less likely to freeze.
• Adding more cores would run more tasks simultaneously, better performance for programs that are programmed for multi-core systems.
• Increasing the cache size would mean that it can store more so it increases access speed to more frequently used instructions.
• A new graphics card would carry out more processes for the CPU and it can improve speed and quality of graphics.
• Changing HDD to SSD would result into faster read and write speed.
• Embedded computers are frequently used to control a device using simple inputs.
• Embedded systems are systems that are designed to be integrated into a larger system.
• Car embedded systems would include interior lighting, cruise control, and audio systems.
• A general purpose machine is a machine that can be used to perform a wide range of tasks.
• CPU speed in an embedded system is typically slow and in a general purpose machine it is typically fast.
• The software in a embedded system has on purpose and can not install a new software whereas in a general purpose machine programs are stored on hard drives.
• Embedded systems are more reliable than general purpose computers as it runs a lot of programs it may be needed to be restarted.