|
Level 0
|
Digital logic
·
Contains digital
circuits, consisting of gates and wires
·
Implements mathematical
logic of all other level.
|
|
Level 1
|
Control
·
Control unit decodes
and executes instructions and moves data through the system
|
|
Level 2
|
Machine
·
Also known as
Instruction Set Architecture level
·
Consists of
instructions that are particular to the architecture of the machine
|
|
Level 3
|
Systems Software
·
Consists of
Operating System and Compliers, interpreters and assemblers
|
|
Level 4
|
Assembly language
·
Acts upon assembled
language from level 5
|
|
Level 5
|
High-level language
·
The level in which
programmers write programs, e.g. Java, C++, etc.
|
|
Level 6
|
User
·
Program execution
and user interface
|
•
Level 6: User
•
Program execution and user interface
•
The level with which we are most familiar
•
Level 5: High-Level Language
•
The level with which we interact when we write programs in languages
such as C, C++, Lisp, and Java
•
Level 4: Assembly Language
•
Acts upon assembled (compiled) language produced from Level 5
•
Acts upon instructions programmed directly at this level
•
Level 3: System Software
•
Operating system
• Controls executing processes
on the system
• Protects system resources
•
Compilers, interpreters and assemblers
• Translate programs into
machine language
• Responsible for multiprogramming,
protecting memory, synchronizing processes etc.
•
Level 2: Machine
• Also known as the Instruction
Set Architecture (ISA) Level
• Machine Language - programs
written in machine language on a hardwired computer can be executed directly
through the electronic circuit without interpreters, translators or compilers.
•
Level 1: Control Unit
•
Decodes and executes instructions
•
Interprets the machine instructions passed to it, one at a time, from
the level above, causing the required actions to take place.
•
Moves data through the system
•
Level 0: Digital Logic
•
Where we find the physical components of the computer system: the
digital circuits (the chips), which consist of gates and wires
•
Common to all systems.
