Unit 2 organization Flashcards
Computer systems cosists of:
Computer systems cosists of hardware and software compiennts and follow the concept of the input, process, output and storage model. This means that a computer system takes in some data as input, processes it in a manner that we have requested and outputs the result. So first we input data which is then processed and sent to either storage or outpued (information)
The cpu is
The cpu is a hardware component of a computer system and can perform basic arthritic, logical, or input/output operations, in order to process data from input devices into useful information. The cpu can process data very quickly but can only process data following instruction.
provides the instructions and processing power the computer needs to do its work.
The CPU is the brain of a computer, containing all the circuitry needed to process input, store data, and output results. The CPU is constantly following instructions of computer programs that tell it which data to process and how to process it. Without a CPU, we could not run programs on a computer.
The cpu contains 4 things. And what are their defintions/ what do they do
The cpu contains 4 things. The control unit (CU) arithmetic logic unit (ALU) memory address register (MAR) and memory data register (MDR)
The ALu performs all the basic athrmtiic, logical, or input/ouput operations. The cu is resposinible for providing the ALU with the data that needs to be processed as well as teh instructions of how the data should be processed
The mar hols the memory address of the data to eb used by the ALU, so that the ALU can fetch the corresponding content from the memory and process it accordingly.
MDr holds the contents of data that is to be used by the alu and then saved to the ram
Machine cycle:
Machine cycle: Fetch, decode execute, store. The control unit requests instructions from the main memory that is stored at a memory’s location as indicated by the program counter (also known as the instruction counter).
processor checks the program counter to see which instruction to run next.
The program counter gives an address value in the memory of where the next instruction is.
The processor fetches the instruction value from this memory location.
Once the instruction has been fetched, it needs to be decoded and executed. For example, this could involve taking one value, putting it into the ALU, then taking a different value from a register and adding the two together.
Once this is complete, the processor goes back to the program counter to find the next instruction.
Grpaghical user interface
Natural language interface
command line interface
menu based interface
Grpagical user interface: have menus and icons
Natural language interface: where the user speaks to teh interface
Command line interface: user types incodes and must be extremely precise or it wont work
Menu based interface: which gives the user a selection of option
Data bus. Address bus
The main difference between address bus and data bus is that the address bus helps to transfer memory addresses while the data bus helps to send and receive data.
Computer systems are binary systems. This means that
Computer systems are binary systems. This means that all the data and instruction that are stored are stored in a sequence of binary digi5s that can take only 0, 1.
computer system and can only have…
1 byte =
computer system and can only have two values either 1 or 0.
1 byte = 8 bits.
One byte can store
One byte can store a single character
The mar:
The mar hols the memory address of the data to eb used by the ALU, so that the ALU can fetch the corresponding content from the memory and process it accordingly.
MDr holds teh data that is to be used by the alu and then saved to the ram
Machine cycle how many stages and what do you do in each stage
The basic operation of a computer is called the ‘fetch-execute’ cycle (also called the ‘machine cycle’).
The computer fetches the instruction from its memory and then executes it.
This is done repeatedly from when the computer is booted up to when it is shut down.
A machine cycle consists of the steps that a computer’s processor executes whenever it receives a machine language instruction. It is the most basic CPU operation, and modern CPUs are able to perform millions of machine cycles per second
Fetch: the first step the fetch-execute cycle carries out is fetching the instruction. The CPU fetches this from the main memory (RAM) and stores it in the CPU temporary memory, called the registers
Decode: Once the instruction has been fetched, the CPU will need to understand the instruction to action it.
When the instruction has been decoded, the CPU can carry out the action that is needed. This is called executing the instruction. The CPU is designed to understand a set of instructions - the instruction set
Fetch:
The CPU is responsible for knowing which instruction it needs to take from the primary memory in order to operate correctly. To do that it sends the appropriate address through the memory (address) bus to the primary memory. The instruction that resides in the specific address is then copied into the data bus and sent to the control unit (CU).
Step 4: store
After executing the instruction and computing the result the CPU then stores the result in the primary memory. To do so, it specifies the address where the result will reside in the primary memory, using the memory (address) bus and sends the data through the data bus. The CPU then checks for the next instruction and repeats the steps described above by fetching, decoding, executing and finally storing the res
Address bus:
data bus:
Address bus: is the connections between mar and main memory
data bus: it eh conecction between mdr and the main memory.
Secondary memory:
Operating system:
system software vs application software:
memory, it holds more information, And it is non volatile
Primary Memory is called volatile memory,
the primary memory is directly accessible by the CPU while the secondary memory is not directly accessible to the CPU of the computer.
Operating system:
It provides an interface between the hardware and the user and the hardware with other application. It is sitting between the hardware system and the users and the software applications and hardware
Systems software vs application software:
System software are general-purpose software primarily used to operate a system with computer hardware. Application software are specific-purpose software primarily used to perform certain tasks.
