Computer Architecture Quiz

System Architecture - PC Architecture Part 1

• The presentation covers PC architecture, focusing on the history, evolution, and key components.
• PC architecture is highly popular due to its open design, readily available details, and a comprehensive understanding of the x86 architecture.
• The presentation will explore the evolution of system architecture, memory technologies, chipsets, and buses.
• Topics covered include a history of computing, IBM PC architecture, CPU generations, and fundamental microprocessor design principles.

Prerequisites

• Students need a firm understanding of microprocessor fundamentals.
• Familiarity with microprocessor-based system design is essential.
• Knowledge of various components and memory types is required.
• Programming skills in assembly language are also beneficial.

General Guidelines

• Slides are provided, so detailed note-taking isn't necessary.
• If a concept is unclear, students should ask the instructor, not a classmate.
• Lab assignments need to apply theoretical knowledge effectively.
• Time is limited, and students must adhere to the scheduled deadlines.

Generations of Computers

• Computer generations are determined by device technology, system architecture, processing mode, and programming languages used.
• The first generation used electromechanical relays and vacuum tubes (1940s-1950s) including ENIAC and UNIVAC.
• The second generation used transistors, core memory and used assembly language, COBOL and FORTRAN. Examples include TRADIC (Bell Labs) and IBM 1620.
• The third generation used LSI and MSI circuits, core memory and allowed multiple applications to run simultaneously. Examples include CDC-6600 and IBM 360 series.
• The fourth generation used VLSI circuits and microprocessors, solid state memories, and GUI-based operating systems. Examples include Cray-1, Cray X-MP, IBM 370, and Macintosh.

History of Computing

• In 1943, Thomas Watson, the IBM chairman, predicted a market for only five computers in total.
• The ENIAC, weighing 30 tonnes and containing 18,000 valves, consumed 25kW of power and could perform 100,000 calculations per second.
• UNIVAC-I launched in 1951, became the first commercially successful electronic computer.

History of the PC

• Altair released the first PC (personal computer) in 1975.
• I/O used front panel switches and LEDs and were mostly for hobbies and hackers.
• Apple II was a commercially successful PC, targeted at home and business markets
• Other manufacturers such as Tandy, Commodore, and TI, also introduced PCs and often had their own proprietary architecture, bus, and OS standards.

IBM PC Architecture

• IBM PC architecture dates back to 1978.
• IBM launched the PC in 1981.
• Open design documentation made IBM PC a successful product.
• The open design allowed different hardware vendors to standardize hardware and software to improve interoperability, making standardization common.
• It is important to compare it with Apple's Macintosh systems.

PC Specifications

• The original IBM PC had an 8088 CPU operating at 4.77 MHz.
• Optional 8087 coprocessor.
• 16K to 640K RAM expandable.
• 160KB floppy disk drives.
• CGA (Color Graphics Adapter) display adapter.
• 84-key keyboard

PC Architecture in Hardware

• The PC architecture's design differs from the microprocessor.
• Firmware abstracts system software (operating system).
• Software (such as Windows APIs) adapts to future hardware demands.
• Peripherals are covered here also.

Input/Output Systems of PC

• The slides explain the components like memory, CPU, input devices (keyboard, mouse, etc.), output devices (monitor, printers), and controllers.
• Details on buses and how they connect these components.

Block diagrams of PCs (XT and AT)

• A block diagram details the internal structure of CPUs, memories, and other essential components such as graphics cards, controllers, and buses.

PC I/O Map

• A table listing the addresses for various hardware devices and functions such as timers, DMA controllers, and communications controllers.

PC Interrupt Usage

• Provides a table listing interrupts (IRQs), their associated numbers (IRQ#) and functions (what the interrupt handles).
• A note on the interrupt vector table assignment.

Processor Interrupt Usage

• Listing of different interrupt functions and their corresponding hexadecimal code.

Memory Map

• Maps different memory addresses to component types for locating data in RAM and BIOS.

Timer Channels

• Enumerates the different timer channels and their associated tasks.

DMA Channels

• Describes various DMA channels and their associated usage.

PC Chipset

• Diagrams showing the components of chipsets (northbridge and southbridge), their functions, and connections to other parts of the system.

Northbridge

• Describes functions of the Northbridge, its connections to the CPU, RAM, and PCI Express bus.

Southbridge

• Describes functions of the Southbridge, its connections to peripherals, PCI, ISA and other devices, and power management.

Intel Chipset

• A visual representation of a particular Intel chipset with its interconnected components.

Recent Trends

• Processors design integrates more functions.
• Reduced cost, better performance chip design.
• Memory controller is combined with processor die.
• New designs like nForce3 use a single chip for both north and southbridge functions.
• Sandy Bridge integrates northbridge functions onto the CPU.

Transformation

• Diagrams show how integrated components result in a better design.
• Shows how CPU, graphics, memory, and networking functions and other interconnected components are integrated into the chipset.

Three Directions

• High integration drives better performance and lower cost.

Contributing Factors

• Advances in VLSI (Moore's Law) are discussed, alongside their effect on CPU speed, memory, peripherals, and bandwidth.

Advances in VLSI

• The era of submicron features (0.09 micro) for more processing power and performance.

Processors

• List of earlier and newer versions of PC Processors covered.

CPU

• Components affecting CPU performance such as ALU width, clock speed, core efficiency, and system interfaces are discussed.
• PC processors incorporate microarchitectural features for parallelism and speed, enabling them to process a greater number of instructions simultaneously, all because of the advancement in transistor budget.

PC Processor Features

• PC processors feature superscalar execution, deep pipelining, out-of-order execution, and speculative instruction execution for better performance.

Path to Performance

• Designers must meet performance targets within limitations of cost, power, and size.
• Application performance should ideally be the primary measure to evaluate performance.
• Speed is sometimes mistakenly viewed as a primary measure of processor performance, rather than application performance.

Path to Performance (continued)

• Advanced semiconductors enable faster operations and signal travel.
• More transistors lead to less execution latency, and parallelizing functions often help.

Intel x86 Architecture

• History and characteristics of the x86 architecture are explored.
• Segmenting memory is important for maintaining compatibility with older systems.
• CISC (Complex Instruction Set Computing): A key architecture characteristics including a large number of instructions, variable lengths, and multiple addressing modes.

8086/88

• Key characteristics of Intel 8086/88 CPU.

80286: Multi-user Configuration

• Key architectural aspects of the 80286 CPU highlighting memory and data characteristics.
• Multitasking, memory protection, and virtual memory features are discussed.

80386: 32-bit Computing

• Key features of the 32-bit architecture.
• Improved architecture and features are explored, including extended registers.
• Support for paging and switching between protected mode.

80486: Functional Integration

• Features of 80486, including its on-chip FPU (floating-point unit) and enhanced caching.
• Simplification and improvement in bus interface.

486 Variants

• Different versions of the 486 processor with variations in clock speeds and cost considerations.

Pentium

• Key characteristics of the Pentium processor including its transistors, external address bus width, and external data bus width, as well as speed grades and bus functionality.

Processor Design - Instruction Set Processors

• Instruction Set Processors (ISPs) execute commands from a predefined set of instructions.
• This functionality depends on the instruction set.

Instruction Set Architecture

• ISA serves as an interface between hardware and software, programming with a standard set.
• ISA specifications for designs and implementation.
• Migration to a different ISA is typically difficult.
• Includes examples like IBM 360/370 and Intel IA32.

Dynamic Static Interface

• Highlights the differences between compile-time and runtime actions and the placement of the interface logic within the software and hardware.

Possible Placements of DSI

• Diagram showing the various levels of abstraction and locations for the dynamic static interface (DSI-1, DSI-2, DSI-3) within the processor architecture.

Instruction Execution

• A visual representation of the steps involved in executing instructions within a processor, including fetching, decoding, and executing, with labels representing the different components' functions.

Features of CISC

• CISC processors support a diverse range of instructions for handling various needs; this allows for more flexibility in software and programming languages.

RISC

• Key aspects of RISC (Reduced Instruction Set Computing) architecture; focusing on speed optimization, instruction set simplification and use of pipelining

RISC (continued)

• Key features highlighted in brief form.

Performance Equation

• Shows the calculation of the total time needed to run a program, including time per cycle and cycles per instruction, based on the processor's nature (CISC or RISC).

ILP Processors

• Description of different Instruction Level Parallelism (ILP) processing types, including pipelined and superscaler instructions execution capabilities.

Superscaler approach

• Diagram showcasing the execution and steps in a superscaler processor where multiple instructions are handled at the same time.

VLIW approach

• Diagram of a VLIW (Very Long Instruction Word) processor architecture where multiple instructions are packed into a single instruction word.

History of Superscalar

• Historical context of the development and introduction of superscalar processors; detailing different projects and commercial products that use the concept for higher processing speed.

CISC superscalar

• Discusses the complexities unique to incorporating superscalar methodology into CISC architectures compared to RISC.
• Highlights the steps in implementation and design differences related to instruction sets and memory architectures.

Superscalar processing

• Five specific tasks involved in proper superscalar operation, including parallel tasks for speed, data, and exception handling.

Parallel decoding

• Describes, in parallel decoding context, the factors and considerations involved in designing, implementing, and comparing scalar vs. superscalar methods.

Decoding and Issue

• Diagram showing the typical flow of decoding instructions and issuing them using scalar issue vs. superscalar instructions issue, highlighting how prefetching and instruction buffering increase processing speed.

Predecoding

• Explains pre-decoding and its advantages in various instruction execution scenarios.
• Describes how predecoding enhances the instruction processing pipeline efficiency.

Superscaler Instruction Issue

• Emphasizes the different aspects of efficient instruction issue for superscalar processors.

Issue Policy

• Different methods to manage and handle data and control dependencies when issuing instructions.

Data Dependencies

• Describes scenarios where instructions are dependent on the results of other instructions, and highlights the Read After Write (RAW) dependency.

False Data Dependencies

• Discusses the Write After Read (WAR) and Write After Write (WAW) data dependency issues; focusing on ways to properly handle conflicts and ordering within a processor without performance hit.

Register Renaming

• Describing how register renaming helps resolve potential conflicts and improves the execution efficiency when potential issues (WAR or WAW) are found in a processor.

Test your knowledge on the evolution of computer processors with this quiz. Questions cover the key differences and advancements introduced by the 80286, 80386, 80486, and Pentium processors. Challenge yourself to recall significant features and architectural changes.