SCO Ed6 Page8 - Phase1 0008/2384

[sorcerer_see]

P.S. I synthesize and re-write in my own words what books teach, write any example programs they contain, solve all exercises they offer, and comment cursively. I list pages done vs total pages, including any roman and appendix numbering.

SCO Ed6 Page8 - Phase1 0008/2384

The set of

• data types
• operations
• features

of each level is called the architecture of that level. Architecture of a level refers to the visible aspects of the level as they present themselves to the user of that level. 

Implementation aspects are not part of the architecture. The study of the design of those parts of a computer system that are visible to programmers is called computer architecture.

But, essentially, computer architecture and computer organization are the same thing.

1.1.3 Evolution of Multilevel Machines

Programs written in machine language (level 1) can be directly executed by the electronic circuits (level 0),
without the need for interpretation or translation.

Hardware
Level 0
Tangible objects:integrated circuits, printed circuit boards,
cables, power supplies, memories, printers ...

Software
Level 1 - ...
Abstract ideas, algorithms, instructions, computer graphical or additive representations (applications)

History
With the first computers the separation between hardware and software was clear. It got gradually more blurred due to the addition, merging and removal of layers of abstraction, as the machines developed and computing became ever more complex. 

But, in the end, hard- and software are logically equivalent, since one can be resembled the other, and, at least theoretically, even be replaced by the other.

The choice between hardware vs software solutions is one of cost, speed, reliability and the expected frequency of changes/additions.