CS - Hardware

• Computer architecture includes the Central Processing Unit (CPU) or microprocessor, von Neumann architecture, arithmetic and logic unit (ALU), control unit (CU) and registers, control bus, address bus, data bus, cores, cache, internal clock, Fetch–Decode–Execute cycle, instruction set for a CPU, embedded systems, input and output devices, sensors, data storage, network hardware, and data storage.
• The central processing unit (CPU) is central to all modern computer systems, including tablets and smartphones, and is often installed as an integrated circuit on a single microchip.
• Embedded systems are used in many security devices, controlling outputs such as temperature, pressure, acoustic, and keypad interface.
• Embedded systems are used in modern sophisticated lighting systems, controlling the lighting taking into account the time of day or day of the week, whether the room is occupied, and the brightness of the natural light.
• Computers are not examples of embedded systems as they are multi-functional and can vary their tasks using different software.
• Embedded systems are used in many applications, from single microcontrollers in MP3 players to complex arrays of multiple units in medical imaging systems.
• Modern cars have many parts that rely on embedded systems to function correctly, including the in-car entertainment system, GPS system, airbags, fuel injection system, ABS braking, vehicle security, traction control, and exhaust emissions.
• Set-top boxes use embedded systems to allow recording and playback of television programmes, which can be operated remotely by the user when not at home using an internet-enabled device or by using the interface panel when at home.
• The CPU is responsible for the execution or processing of all the instructions and data in a computer application.
• The CPU consists of the control unit (CU), arithmetic and logic unit (ALU), registers and buses.
• Early computers were fed data while the machines were actually running, which meant they couldn’t operate without considerable human intervention.
• John von Neumann developed the concept of the ‘stored program computer’ in the mid-1940s, which has been the basis of computer architecture ever since.
• One advantage of using QR codes rather than traditional bar codes is that they can store more data.
• One disadvantage of using QR codes is that they are not as widely recognized as traditional bar codes.
• A square QR code contains 40 × 40 tiny squares (pixels) where each tiny square represents a 0 or a 1.
• The user could be sent to a fake website or a virus could be downloaded.
• The data in Figure 3.14 can be used to design the barcodes for 9003, 12576, and 05889.
• The three large squares at the corners of the QR code are used to identify the code.
• Unlike normal QR codes, software to do this isn't usually free.
• Frame QR codes come with a 'canvas area' where it is possible to include graphics or images inside the code itself.
• Newer QR codes, called frame QR codes, are used because of the increased ability to add advertising logos.
• The von Neumann architecture had the following main novel features: the concept of a central processing unit (CPU or processor), the CPU was able to access the memory directly, computer memories could store programs as well as data, and stored programs were made up of instructions which could be executed in sequential order.
• The main components of the CPU are the Control Unit (CU), Arithmetic & Logic Unit (ALU) and system clock.
• The Arithmetic & Logic Unit (ALU) allows the required arithmetic or logic operations to be carried out while a program is being run, and it is possible for a computer to have more than one ALU to carry out specific functions.
• Multiplication and division are carried out by a sequence of addition, subtraction and left or right logical shift operations.
• The control unit reads an instruction from memory, stores the address of the location where the instruction can be found in the Program Counter (PC), and then interprets the instruction using the Fetch–Decode–Execute cycle.
• During the Fetch–Decode–Execute cycle, signals are generated along the control bus to tell the other components in the computer what to do.
• Vending machines use actuators to dispense items, operate the chill system pump, and control motors.
• Barcode scanners (readers) are an example of an input device.
• Vending machines use a wireless modem to send data back to the vending machine company.
• Vending machines use sensors to show the position of gates which hold the items in place and indicate if any dispensing rows are empty.
• Updates to the GPS device in a car are required every six months, explain how the device is updated without the need to take the car to the garage every six months.
• Embedded systems in vending machines use a display to show prices, change, and item description.
• Embedded systems in vending machines use sensors to monitor the temperature, detect tampering, and ensure the correct environment for items.
• Vending machines use embedded systems to control a variety of functions including coin counting, item selection, and data reporting.
• A barcode is a series of dark and light parallel lines of varying thickness, with the numbers 0 to 9 represented by a unique series of lines.
• Many ‘white goods’ such as refrigerators, washing machines, microwave ovens, and so on, are controlled by embedded systems.
• Each digit in the barcode is represented by bars of 1 to 4 blocks thick.
• Embedded systems in vending machines use an input pad to make selections and a coin counter to ensure correct money is entered.
• Many of the bulbs available today use LEDs and come in a variety of colours to change the mood.