什麼是體系結構

體系結構對應的英文單詞是architecture，它的另外一個意思是建築，真是形象。計算機體系結構之于建築，就像pn結之于混凝土。混凝土可以澆鑄成各種承重的構件，pn結也可以構造成各種function unit。

1. 引用Patterson and Hennesy <<計算機體系結構:量化研究方法>>

(1) IBM coined the term computer architecture in the early 1960s.

    Amdahl, Blaauw, and Brooks [1964] used the term to refer to the programmer-visible portion of the IBM 360 instruction set.

    …the attributes of a computing system as seen by the programmer, i.e. the conceptual structure and functional behavior, as distinct from the organization of the data flows and controls the logic design, and the physical implementation.

    – Amdahl, Blaaw, and Brooks, 1964

=指令集對于程式員的可見部分

由于資料流、控制邏輯的組成和實體實作的不同造成的，主要是硬體層面上包括硬體和硬體實作的idea

(2) Computer Architecture =

    Instruction Set Architecture +

Machine Organization + ......

和(1)相比主要是發展了指令集的設計，硬體層面趨于成熟

(3) Computer Architecture’s Changing Definition

1950s to 1960s, computer architecture:

                                                       Computer Arithmetic

1970s to mid 1980s, computer architecture:

Instruction Set Design, especially ISA appropriate for compilers

    1990s, Computer Architecture:

Design of CPU, memory system, I/O system, multiprocessors, networks.

2010s, Computer Architecture:

Self adapting systems?

                                Self organizing structures? DNA Systems/Quantum Computing?

(4) Instruction Set Architecture

    --Organization of Programmable Storage

    --Data Types & Data Structures: Encodings & Representations

    --Instruction Set

    --Instruction Formats

    --Modes of Addressing and Accessing Data Items and Instructions

    --Exceptional Conditions

(5) Computer Organization

    --Capabilities & Performance Characteristics of Principal Functional Units

      e.g., Registers, ALU, Shifters, Logic Units, ...

    --Ways in which these components are interconnected

    --Information flows between components

    --Logic and means by which such information flow is controlled

    --Choreography of FUs(function unit) to realize the ISA

    --Register Transfer Level (RTL) Description

2. 引用Steve Furber <<ARM System-On-Chip Architecture>>

(1) Computer Architecture

    Computer Architecture describes the user's view of the computer. 我對這個觀點比較認同

The instruction set, visible registers, memory management table structures and exception handling model are all part of the architecture.

(2) Computer organization

    Computer organization describes the user-invisible implementation of the architecture. The pipeline structure, transparent cache, table-walking hardware and TLB (translation look-aside buffer) are all aspects of the organization.

...invisible to programmer