計概4

1.Generations of programming languages:
  Problems solved in an environment in which the human
  must conform to the machine's characteristics

2.Second-generation Assembly language:
  A mnemonic system for representing machine
  instructions
  * Mnemonic names for op-codes
  * Identifiers: Descriptive names for memory locations,
                 chosen by the programmer
 
     Assembly Language Characteristics-->
     * One-to-one correspondence between machine
       instructions and assembly instructions
      - Programmer must think like the machine
     * Inherently machine-dependent
     * Converted to machine language by a program
       called an assembler
3.Third Generation Language:
  * Uses high-level primitives
    - Similar to our pseudocode in Chapter 5
  * Machine independent (mostly)
  * Examples: FORTRAN, COBOL
  * Each primitive corresponds to a sequence of
    machine language instructions
  * Converted to machine language by a program
    called a compiler