Computer Architecture and CPU components

Computer Architecture & Von Neumann Architecture

• The Central Processing Unit (CPU) functions as the core of modern computer systems.
• CPU is also known as a microprocessor or processor.
• The CPU is made of a processor, a control unit, an Arithmetic Logic Unit (ALU), and a system clock

Components of the CPU

• The processor contains the Arithmetic and Logic Unit (ALU).
• The control unit oversees memory, processor, and input/output device operations.
• The Arithmetic Logic Unit (ALU) performs calculations and logic operations.
• A system clock produces timing signals using the control bus.

Buses

• Buses transfer data between components.
• Address bus operates unidirectionally.
• Data bus operates bidirectionally.
• Control bus operates bidirectionally.

Immediate Access Store (IAS)

• Immediate Access Store stores the instructions to be processed, fetched by the CPU.
• Register abbreviations such as CIR, MAR, MDR, PC and ACC all exist in the architecture.

The Fetch-Execute Cycle

• PC holds the address of the next instruction.
• This address is copied to the MAR via the address bus.
• The instruction at that address is temporarily copied into the MDR.
• The instruction in the MDR then transfers to the CIR.
• The PC increments by one, indicating the next instruction.
• The instruction is decoded, then executed.

Stored Program Concept

• Instructions are stored in main memory.
• Instructions are fetched, decoded, and executed by the processor.
• Programs can be moved to and from the main memory.

Memory Concept

• Computer memory is split into partitions, each with an address and contents.
• An Instruction Set encompasses all commands a CPU can process; these commands are machine code.

Cores, Cache and Internal Clock

• Clock dictates the timing of computer processes.
• A higher clock speed increases processing; however, overall performance may not improve.

Overclocking

• Using clock speeds beyond the computer's design can cause unsynchronized operations.
• Overclocking can lead to computer instability.
• Overclocking can lead to serious overheating of the CPU.

Length of Data Buses

• Wider data buses improve computer performance.
• Cache memory is located within the CPU.
• Cache memory enables faster data access, boosting CPU performance.
• Larger cache memory size improves CPU performance.

Input Devices

• Two-dimensional scanners input hard-copy documents into electronic form for computer storage.
• The document is positioned on a glass panel and illuminated by bright light.
• The scanner captures an image of the document and sends it to a lens.
• The CCD converts the focused image into a digital image, forming the scan.

Optical Character Recognition (OCR) Software

• OCR converts scanned files into text format, while photo scans create JPEG images.
• Three-dimensional scanners can assess solid objects, producing three-dimensional images.
• These Scanners capture images from points x, y, and z using methods like lasers.
• Scaned Images are compatible with CAD or serve in 3D printing for creating models.

Application of 2D Scanners at an Airport:

• 2D Scanners can use OCR to digitize passport images with text stored as ASCII.
• Facial recognition software compares a live photograph to the passport photo.
• Algorithms compare distances between eyes and nose width for verification

Barcode Readers/Scanners

• Barcodes use dark/light parallel lines of different widths.
• Digits 0-9 are represented by unique barcodes.
• Guard bars divide left and right barcode sides, allowing scanning from any direction.
• Red lasers or LEDs read barcodes.
• Reflected Light Patterns convert to digital.

Quick Response (QR) Codes

• QR codes, a type of barcode, feature filled-in dark squares on a light background.
• They can store up to 7000 digits, offering advantages like storing website addresses that eliminate manual typing

Digital Cameras

• Microprocessors manage adjustments like shutter speed and focus.
• It captures an image by directing light through the lens onto light-sensitive cells made of pixels.
• Keyboard can connect to a computer via USB or wirelessly.
• Each keystroke is assigned an ASCII value and converted into a digital signal.

Various Input Devices

• Mouse or trackball traditional mechanical ball use USB, while modern types use red LEDs for movement.
• Microphones transform sound into electric signals via diaphragm vibration.
• Sound cards convert these signals into digital values for storage of voice recognition

Touchscreens

• Capacitive touchscreens, a medium-cost technology, contain multiple layers and create electric fields within glass plates.
• The screen's coordinates are determined by an on-board microprocessor when touched.
• Infrared heat touchscreens use glass and need a warm object to carry an input operation.
• Resistive touchscreens use polyester layers, completing circuits when touched

Sensors

• Sensors read physical characteristics and Need a ADC to convert the data to a digital format.
• Acoustic sensors convert sound to electric pulses, accelerometers measure motion, and flow sensors measure liquid/gas levels.
• Infrared sensors are active or passive. Level sensors detect solids, liquids, or gas height.
• Light sensors produces current based on brightness. Magnetic sensors detect magnetic changes.
• Moisture sensors determine water content, pH measures acidity ,Proximity sensors detect nearby objects, and temperature sensors measure warmth.

Control of Street Lighting

• Light sensors send data to the ADC, digitizing the data to send to the microprocessor.
• The microprocessor samples data, compares values, and sends signals to street lamps to switch them on if needed.

Output devices

• Inkjet printers create one-off pictures and documents.
• Inkjet Document data is formatted by the printer driver and temporarily stored in a printer buffer.
• The Printer prints one line at a time it signals the processer when more data is needed.

Laser Printers

• Laser printers Print flyers quickly by using dry power and static electricity.
• Printing drum is charged positively, then a laser removes the charg in pattern.
• Toner sticks to the charged areas, transfers to paper, then a fuser permanently seals it with heat.
• Discharge removes all electricity for next page.

3D Printers

• 3D Printers create solid models using layers of powdered resin, ceramic powder based on CAD designs.
• 2D and 3D Cutters can cut glass, crystal, metal, and wood.
• Actuators Convert electrical signals to mechanical processes in control applications.

Loudspeaker and Headphone Audio

• Speakers are used to amplify produce sound via conversion of digital data to DAC voltage and the vibration of a cone.
• LCD monitors use backlight and liquid crystal with pixels in groups of 3.

LCD Backlights

• LEDs are used as an enhancement over CCFL for longer, faster, better display.
• Light projectors use DLP and LCD to project output on screens/whiteboards.
• Uses millions of micromirrors which tilt and create light.

Digital Light Projectors (DLP)

• Project light onto screens, and create white split into Primary colours.
• LCD Projectors use an older technology that is powered by light being shone through LCD screens, before being directed to lenses towards the screen

Memory Storage

• RAM (Random Access Memory) enables immediate data storage and access for active use.
• RAM is volatile and temporary, storing actively used data and files for immediate access.
• RAM is writeable, readable, and its capacity affects computer speed where the more capacity will increase the speed .
• Dynamic RAM (DRAM) vs. Static RAM (SRAM) types offer different performance trade-offs.
• DRAM, uses transistors that needs to be constantly refreshed. DRAM is less expensive and consumes less power
• SRAM holds each bit and is faster data access time. CPU uses SRAM.

Virtual Memory

• When RAM runs out of capacity, virtual memory, which allows the system to use parts of the storage drives like the HOD or SOD, can be used.
• ROM is Non-volatile/Permanent.
• ROM stores startup/basic input output systems an HDD data is saved permanently in sectors/tracks and has slow data access.

Solid State Drive (SSD) Advantages:

• SSDs stores movement by manipulating electrons, with no movement like HDD.
• SSD's are smaller, less fragile/lighter than hard drives are more reliable and take up less power.
• The access is quicker than and HOD but are questionable.

Offline Storage Options:

• CD/DVD discs used red lasers to write data on the surface and are double layered to increase the capacity
• CD/DVD discs use dual layering.
• Blu-Ray Discs use blue lasers to increases data capacity. Blu-Ray Discs encrypt for safety.

USB Flash Memory Devices

• USB Devices are lightweight, are small for backing up but must be treated with care.
• Cloud storage is off site server storage for redundancy.

Type Data Storage:

• Public Cloud is third party ran.
• Hybrid Cloud is where user has their own and third party storage option
• Private Cloud- Is cloud that is entirely private for a client

Embedded System

• Is a combination of hard and software used to do specific tasks.
• Microcontrollers, CPU-RAM , system on chips. The general flow of data used in these systems if input sent to microprocessor that thens sends the signals.
• Embedded Systems have many tasks like in vending machines, cars, etc as well as advantage/disadvantages.

Network Hardware

• Is used to connect networks. The network access card is the most important part of the system.
• Has MAC which shows the device serial number. Comes in (UAA) or the (LAA).
• IP address allocated as needed by Dynamic Host Configuration Protocol (DHCP)
• IPv4 is the Internet protocol widely in use. Whereas the IPv6 (Internet Protocol version 6) is the new version of the protocol .

Routers

• Routers is the process of routing different sources and is the efficient path. Routers uses IPS table to read.
• Routers Role in IP Address assignment acts as the DHCP.

The router connects a local network to the internet