Essential Computer Architecture Acronyms

Acronyms in Computer Architecture

• ALU stands for Arithmetic Logic Unit
• ASCII is the American Standards Code for Information Interchange
• ANSI refers to the American National Standards Institute
• BCD means Binary Coded Decimal
• CD denotes Compact Disk
• CD-ROM is a Compact Disk-Read Only Memory
• CPU is the Central Processing Unit
• CISC: Complex Instruction Set Computer
• DRAM: Dynamic Random-Access Memory
• DMA: Direct Memory Access
• DVD: Digital Versatile Disk
• EPROM: Erasable Programmable Read-Only Memory
• EEPROM: Electrically Erasable Programmable Read-Only Memory
• HLL is High-Level Language
• I/O: Input/Output
• IAR: Instruction Address Register
• IC: Integrated Circuit
• IR: Instruction Register
• LRU: Least Recently Used
• LSI: Large-Scale Integration
• MAR: Memory Address Register
• MBR: Memory Buffer Register
• MMU: Memory Management Unit
• MSI: Medium-Scale Integration
• OS: Operating System
• PC: Program Counter
• PCI: Peripheral Component Interconnect
• PROM: Programmable Read-Only Memory
• PSW: Processor Status Word
• PCB: Process Control Block
• RALU: Register/Arithmetic-Logic Unit
• RAM: Random-Access Memory
• RISC: Reduced Instruction Set Computer
• ROM: Read-Only Memory
• SCSI: Small Computer System Interface
• SMP: Symmetric Multiprocessors
• SRAM: Static Random-Access Memory
• SSI: Small-Scale Integration
• ULSI: Ultra Large-Scale Integration
• VLSI: Very Large-Scale Integration
• VLIW: Very Long Instruction Word

Structure and Function in Computer Systems

• A computer is a complex system with millions of electronic components.
• Complex systems, like computers, are understood via their hierarchical nature.
• A hierarchical system contains interrelated subsystems, each hierarchical until the lowest subsystem level.
• The hierarchical nature is essential for the design and description of complex systems.
• Designers focus on one level of the system at a time.
• Each level comprises components and their interrelationships.
• Behavior at each level relies on an abstracted characterization of the level below.
• Designers consider both structure (component interrelations) and function (operation of individual components within the structure).

Computer Components

• The CPU is a complex and interesting computer component.
• Computer's data processing is performed by the Arithmetic and Logic Unit (ALU).
• Registers provide internal storage to the CPU.
• CPU interconnection provides for communication among the control unit, ALU, and registers.

Von Neumann Architecture Concepts

• Data and instructions are stored in a single read-write memory.
• Memory contents are addressable by location regardless of whether it's data or instruction.
• Code execution is sequential unless a jump instruction is encountered.

Program Concepts

• Almost any function can be realized with hardwired logic components, like in a calculator.
• Hardwired systems are inflexible.
• General-purpose hardware can perform different tasks with the correct control signals.
• Instead of rewiring, control signals are supplied to change tasks.

Program Creation

• Each step activates a set of control signals for general-purpose logic.
• Each step involves an arithmetic or logical operation.
• Programming involves the sequence of steps, not rewiring.

Instruction Interpreter

• The device turns instruction codes into control signals for arithmetic and logic hardware.

Encoding Instructions

• Unique binary patterns identify operations to be performed.
• Examples include simple addition machines and X86 Encoding.

Simplified 2-Step Instruction Cycle

• Instruction cycle differs from a clock cycle.
• The two steps are Fetch and Execute.

Fetch Cycle

• Program Counter (PC) holds the address of the next instruction.
• The processor fetches the instruction from the memory location pointed to by the PC.
• It increments the PC unless otherwise instructed.
• The instruction is loaded into the Instruction Register (IR).
• The processor interprets the instruction and performs necessary actions.

Execute Cycle

• Processor-memory actions include data transfer between the CPU and main memory.
• Processor I/O involves data transfer between the CPU and I/O module.
• Data processing includes arithmetic or logical operations on data.
• Control involves alteration of the sequence of operations, like a jump.
• The execute cycle could be a combination of the elements listed above.