04 Computer Components & Operations

Core Elements of Computer Operation

• Computers are utilized daily for continuous computation.
• Examples are laptops, cameras, tablets, smart devices and GPS.

Key Computer Components

• Processor executes program instructions.
• Operating System manages common operations making the computer usable.
• Software refers to programs.
• Instructions are what the processor needs to perform a task.
• Fetch/Execute Cycle carries out the instructions.
• Memory stores data.
• Hardware constitutes the computer’s physical components.

Understanding New Apps

• New apps are often long sequences of bits, typically not typed one by one by programmers.
• These bits are produced through a program
• Programs consist of instructions in an algorithm, lines are sparse with a few symbols, and they may include English words naming available facilities.

Software Characteristics

• Specialized training may be needed to derive a program's meaning.
• Typographical errors, even minor ones, can lead to software bugs.

Software Organization

• System software is structured in layers where each layer utilizes services from the layer below and provides services to the layer above.
• This promotes shared effort, reusability, consistent behavior, and easier bug fixing.

Instruction Execution

• Computers execute instructions through the Fetch/Execute Cycle.
• The cycle involves getting the next instruction, figuring out what to do, gathering data, executing the instruction, saving the result, and repeating the process.
• The process repeats billions of times per second.

Anatomy of Computers

• Regardless of technology, basic computer architecture comprises five key parts: memory, control unit, Arithmetic Logic Unit (ALU), input unit, and output unit.

Registers Role

• Registers are memory areas for storing data elements and instructions during computer operations.

Memory Attributes

• Memory stores running programs while also storing operated data.
• Memory discrete locations are organized as a sequence.
• In modern memory, each location is one byte (8 bits).
• Memory has addresses and values.
• Every memory location has an address starting with 0.
• Values are recorded or stored in memory locations.
• Memory has finite capacity
• Memory locations have limited sizes.
• Data may not fit in its memory location.

Common Memory Visualization

• Memory is represented as boxes each holding 1 byte with addresses displayed above the box.

Byte Uses

• A 1-byte memory location can store one ASCII character, part of a number, or part of an instruction.
• Four-byte blocks are commonly referred to as memory "words."
• The software determines usage of a memory location's content.

RAM Information

• Computer memory is known as Random Access Memory (RAM), which allows access to memory locations in any order.
• RAM is measured in megabytes (MB) or gigabytes (GB).
• Sufficient RAM provides necessary space for programs and data.

Control Unit Role

• The control unit facilitates the Fetch/Execute Cycle.
• The circuitry fetches instructions from memory and executes the Fetch/Execute Cycle.

ALU Core Functions

• The Arithmetic/Logic Unit (ALU) performs mathematical operations.
• Circuits within the ALU can add numbers using logic gates to implement operations like AND and OR.
• ALUs can multiply and compare numbers using separate circuits for each machine instruction.

I/O Units Importance

• Input and output units are essential for computers to receive and send information.
• A computer cannot function without them.

Defining Peripherals

• Peripherals connect to input/output ports to provide input or receive output, but are not part of the processor.
• They function as specialized encoding and decoding gadgets.

Peripheral Examples

• Keyboards encode keystrokes into binary.
• Monitors decode information for display.
• Peripherals handle the physical aspect of operations.

Portable Storage Facts

• Peripherals like USB drives and hard disks serve as both input and output.
• They function as storage devices.
• Hard disks act as primary peripherals with tight computer integration.

Device Drivers Role

• Peripheral devices are "dumb", requiring software drivers for intelligible operation.
• Device drivers provide standard meaning and behavior to peripherals.

Machine Instructions Breakdown

• ADD 4000, 2000, 2080
• It adds the numbers in memory locations 2000 and 2080 and stores the result in location 4000.
• Computer instructions encode memory addresses, not numbers.
• Indirect reference refers to a value by its memory address.

Machine Instructions Operation

• Computers determine the instruction by using the Program Counter (PC), which points to the next instruction's address in memory.
• The computer increases the PC by 4 after each instruction, where instructions use 4 bytes of memory.

Branch and Jump Operation

• Not all instructions need to be in a strict order
• The instruction contains a memory location to go to next
• The computer "jumps" or "branches."

Fetch/Execute Cycle Steps

• Cycle includes Instruction Fetch (IF), Instruction Decode (ID), Data Fetch (DF) / Operand Fetch (OF), Instruction Execution (EX), and Result Return (RR) / Store (ST).

Instruction Fetch Explanation

• Execution begins by transferring the instruction from the PC's address to the control unit.
• Bits of instruction are placed into the CU decoder circuit.
• After fetching, the PC can prepare for the next instruction.

Instruction Decode Facts

• The ALU is set up for the operation.
• The decoder finds the memory addresses (Source Operands).
• Most instructions operate on two data values
• The decoder identifies the destination address and determines the ALU operation, setting up the ALU for the ADD instruction.

Data Fetch Purpose

• Data is retrieved from the location of its memory and is operated on.
• Values at memory are then copied to ALU circuitry.
• Data values are not destroyed in the memory.

Instruction Execution Function

• The addition circuit adds the source operands and their sum is held in ALU circuitry.
• This is the actual computation.

Result Returns Impact

• The RR process returns the result to the specified memory location, after which the cycle repeats.

Clock Significance

• The speed of the system is determined by how many cycles that are done each second
• The execution clock rates are in Megahertz(MHz) or millions of hertz
• A 1,000 MHz clock ticks a billion times per second which is 1 GHz

Nanosecond Relation

• A 1 GHz clock has one billionth of a second or one nanosecond to run the Fetch/Execute.

Pipelining Benefits

• Modern computers start new instructions each clock tick, using a pipeline concept similar to an assembly line.
• Pipelines fetch and pass along instructions, allowing continuous fetching of others.

ALU Operations Information

• Computers have a limited set of instructions, around 100, recognized by decoder hardware .
• Typically, there are about 20 different kinds of operations.
• Every computation is a combination of these instructions

Source Code Translation

• Source code is what programmers write, such as this.Opacity += 0.02.
• It's converted into assembly, which uses words instead of 0s and 1s, then to binary.
• The bits needed by the processor are object code, binary code, or just binary.

Compiler Functions

• A compiler is a program that translates another program into assembler language and each language requires its compiler.
• The assembly language is converted to machine language by an assembler.

Integrated Circuit Importance

• Integrated Circuits run at GHz rates due to their small processor chips because Electrical signals can travel 30 cm in a nanosecond.

Integration Details

• Early computers were made from separate parts (discrete components) wired together by hand
• Each transistor, resistor, and capacitor needed to be connected to wires of another.
• Active components and the wires that connect them are manufactured together from similar materials by a single (multi-step) process
• IC technology places transistors in the silicon along the connection and is small and reliable.

Photolithography Process

1. Deposit aluminum on the silicon
2. Cover with photoresist material, and place a mask over it
3. The mask pattern creates the features with UV light exposure
4. Unexposed areas are washed away
5. Hot gases etch the layer above
6. The remains create the patterns.

Transistors Basic Details

• A transistor is a connector between two wires
• It controls the charge that flows between the wires.
• A transistor being used is MOS or Metal Oxide Semiconductor.

Semiconductor Basics

• Semiconductors conduct and don't conduct electricity, controlling for computer construction.
• Silicon in a channel conducts electricity with a charged field from a positive gate.
• Electrons attract from the silicon until the field is removed, and the channel disperses.

ALU in Relation to Transistors

• Logical ALU's such as AND or OR built from transistors for complicated combinations.
• Memory and control units are made by parts.
• Eventually, ALU then processor.

Memory Access

• This refers to the time necessary to read or write the content of a memory location.

Regarding Cost

• This is the cost by stored byte

Memory of Volatility

• Volatile memory loses information when turned off.
• Persistent memory stays safe when computers are turned off.

Memory Size

• Memory size refers to the maximum a given technology has.

Main Memory Tradeoff

• The amount of each memory should be optimized and cost-effective.

Caching for RAM and CPU registers

• This allows transfer times to be optimal.

Storage as a Standard

• Hard disks are known to have the safest storage

HCI Implementations

• Peripherals execute it but implement data entering and exiting at the external computer.
• Details are put onto cards that connect to the BUS "data highway".

BIOS Function

• The BIOS manages tasks such as checking hardware resources, initializing programs, diagnosing issues, and searching for the boot sector.
• BIOS is stored in a ROM provided by a computer manufacturer.

Processors and Processes

• A processor executes programs while processes load and execute in main memory and their states depend on the OS.
• Processor life will be completely controlled by the OS.

Mutlitasking

• OS allow process execution
• The processor allows one process a time with the OS assigning processor usage.
• The resources should be properly used for all processes.

Virtual Memory Accesses

• When main memory usage is full, processes will be stored in the secondary memory and read again.
• This only effects speed, but not function, reading processes requires additional time.

OS List

• PC: Windows, Apple Mac OSX, Linux
• Mobiles: Android, iOS
• Mainframes: Unix, IBM

Software's Stored and Translated

• Task performed is done by large application program > commands compiled with assembly instructions > Assembly translated into computer's binary > Cycle executed > Processor provides logic

Software Summary

• Software's are in coded language with terms and operations
• Repeat fetches of each instruction (by PC), decodes operation, retrieves, performs and stores result.
• Data isn't referred to directly nor machine but indirectly.
• Computes are done on data on referenced locations of a instruction.
• This process involves components with a processor and bytes that stores data and the running programs in the Alu.
• Coding involves sophisticated programming to create complex OS.
• Basics of IC involves integrating the components with production by photo effect to control conductivity.