Organization vs architecture exercise

Author

Clayton Cafiero

Published

2025-09-09

Computer organization and computer architecture

It’s important that we understand the difference between organization and architecture.

Architecture is abstract—but precise. It’s often likened to a blueprint for a building. The blueprint isn’t the building, but it tells us how big the building is, how many storeys it has, what rooms it has, the purpose or function of each room, and so on. Architecture is also referred to as the programmer’s view of a machine (blueprints tell us what a building should look like).

Organization, on the other hand, is the concrete realization of a design. It’s like the building made from a blueprint. There are many details of a building that aren’t captured by a blueprint—specific details, the grade of lumber, the brand of sheetrock, the actual electrical wiring and plumbing, and so on.

Here are some items which can be classified as belonging to organization or architecture (but I won’t say which yet).

  • The size of the smallest addressable element of memory (bit, nibble, byte, word)
  • The buses which connect components (e.g., CPU and RAM, or memory and I/O devices, etc.)
  • The supported data types (e.g., int, float, char, etc.).
  • The addressing scheme for assigning addresses to memory locations.
  • The instruction set of the CPU (e.g., ADD, MULT, SUB, DIV, LOAD, STORE, etc.).
  • The size main memory available on a machine (e.g., 16 GB RAM).
  • The size of cache memory (fast memory near the CPU).
  • The datapath, which is the collection of hardware components that store and process data inside the CPU.
  • The clock speed which regulates the CPU.
  • The number of arithmetic logic units in a CPU.

Which items on this list do you think belong to architecture, and which belong to organization? Justify your choices.

item architecture organization comment
size of smallest addressable element of memory
buses which connect components
supported data types
addressing scheme
instruction set
size of main memory
size of cache memory
datapath
clock speed of CPU
number of ALUs (arithmetic logic units)

© 2025 Clayton Cafiero.

No generative AI was used in writing this material. This was written the old-fashioned way.