DCIT 65

• Computer Architecture


  Attributes of the system that are visible to the software programmer and have a direct impact on the logical execution of a program
• 3 main categories design of architecture

  - System Design

  - Instruction Set Architecture

  - Micro Architecture
• System Design


  Contains hardware components that are used for building the system.
• Instruction Set Architecture


  Includes all the instructions provided to the computer system.
• Micro Architecture


  Give minute detail about storage element
• Computer Organization


  Way the various components of a computer system are interconnected and work together
• Computer device


  Made up of various elements which help in its effective functioning and processing
• Components of a computer system

  the primary elements which make the functioning of an electronic device smooth and faster
• 5 basic components of a computer system

  - Input Unit

  - Output Unit

  - Memory Unit Control

  - Unit Arithmetical and Logical Unit
• Input Unit


  A computer will only respond when a command is given to the device.
• Output Unit


  Command a computer to perform a task, it reverts for the action performed and gives us a result
• Memory Unit


  We enter the data into the computer using an input device, the entered information immediately gets saved in the memory unit of the Central Processing Unit (CPU).
• CPU

  Central Processing Unit
• Control Unit


  The core unit which manages the entire functioning of the computer device. It is one of the most essential components of the computer system.
• Arithmetical and Logical Unit


  - all the mathematical calculations or arithmetic operations are performed

  - It can also perform actions like a comparison of data and decision-making actions
• ISA

  Instruction Set Architecture
• Instruction Set Architecture


  Part of the abstract model of a computer that defines how the CPU is controlled by the software
• Instruction Set Architecture


  Acts as an interface between the hardware and the software, specifying both what the processor
• Instruction Set Architecture


  Encompasses all the information necessary for programmers to write a machine language program that will run correctly, including instruction, register, memory access, I/O devices, etc.
• Instruction Set Architecture


  Allows computer designer to talk about the functions independently from the hardware that perform them.
• RISC

  Reduced Instruction Set Computer Processor
• RISC Processor


  a microprocessor architecture with a simple collection and highly customized set of instructions
• RISC Processor


  It is built to minimize the instruction execution time by optimizing and limiting the number of instructions.
• RISC Processor


  It means each instruction cycle requires only one clock cycle, and each cycle contains three parameters: fetch, decode and execute.
• RISC Processor


  Perform various complex instructions by combining them into simpler ones.
• RISC chips


  require several transistors, making it cheaper to design and reduce the execution time for instruction.
• Advantages of RISC

  - The RISC processor's performance is better due to the simple and limited number of the instruction set.

  - It requires several transistors that make it cheaper to design.

  - RISC allows the instruction to use free space on a microprocessor because of its simplicity.

  - RISC processor is simpler than a CISC processor because of its simple and quick design, and it can complete its work in one clock cycle.
• Disadvantages of RISC Processor

  - The RISC processor's performance may vary according to the code executed because subsequent instructions may depend on the previous instruction for their execution in a cycle.

  - Programmers and compilers often use complex instructions.

  - RISC processors require very fast memory to save various instructions that require a large collection of cache memory to respond to the instruction in a short time.
• CISC


  Complex Instruction Set Computer
• the Intel


  Developed Complex Instruction Set Computer
• CISC Processor


  A large collection of complex instructions that range from simple to very complex and specialized in the assembly language level, which takes a long time to execute the instructions.
• CISC


  Reducing the number of instruction on each program and ignoring the number of cycles per instruction.
• CISC


  It emphasizes to build complex instructions directly in the hardware because the hardware is always faster than software.
• CISC chips


  Slower as compared to RISC chips but use little instruction than RISC.
• Advantage of CISC.


  - Ability to perform complex instruction.

  - Programs require fewer instruction to execute.

  - Greater hardware support for performing complex instruction.
• Disadvantage of CICS.


  - Increased complexity can lead to slower processing time.

  - Larger chip size can lead to increased costs.
• Types of Memory Hierarchy

  - External Memory/ Secondary Memory

  - Internal Memory/ Primary Memory
• External Memory/ Secondary Memory

  - Hard Disk Drive (HDD)

  - Solid State Drive (SSD)

  - USB Flash Drive

  - External Hard Drive

  - Memory Card

  - NAS or File Servers

  - Cloud Storage
• Internal Memory/ Primary Memory

  - Random Access Memory (RAM)

  - Cache Memory

  - Registers

  - Memory Controllers

  - On-Chip Memory (L1,L2, L3 Cache)

  - Non-volatile Memory (ROM)
• Registers


  - Tiny, lightning-fast memory units inside the CPU.

  - They store data temporarily during processing, making instructions run smoothly and managing data efficiently within the CPU.