1. 4 – History of Programming Languages
CSCI N201
Programming Concepts and Database
4 – History of Programming Languages
Lingma Acheson
Department of Computer and Information Science, IUPUI

2. Progression
Hardware
Machine code
Assemblers
Compilers
Interpreters

3. Hardware encoding Physically wiring the machine
Changing the hardware structure
Programming in this way is
- Very difficult
- Extremely tedious
- Error prone
- Hard to fix problems

4. Hardware encoding Change physical structure of machine
Extremely tedious
Very difficult
Prone to error

5. Machine Language Stored Language Concept Von Neumann
Treat Instructions as data
Each opcode built into ALU has a number
Abniac

6. Machine Language Abniac Illustrate the usage of machine languages
All commands have a number
Store – 1
Add – 2
Compare – 3
All cells (place holders) have a number 0 – 99, to store instructions and values
Machine codes in second blue column
Description in third blue column
Output window in right most window frame

7. Machine Language
Program can be created by selecting a command, enter values and click on “OK” button
Need to run the program after it’s created - click on “Run”.
Need to tell the program where to stop running - click on a cell and click “Halt”.
“File -> New” to refresh and create a new program.

8. Machine Language
Run Abniac!
Create your own Abniac program!

9. ASCII table

10. Assembler Mnemonics for opcodes Labeled cells, e.g. cell x
E.g. use “Add” to mean “add”
Labeled cells, e.g. cell x
somewhat easier on programmers
E.g. Sto 2
Add 3
Lod 5 …

11. High-level Language Typed in near-human language
Converted to assembler
Much easier on programmers
Can be assembled or compiled
Language is still very precise, but more readable
E.g. If (x=2) then
response.write “two”
else
response.write “zero”