1.3.7 High and Low Level Languages

Question 1

Explain what is meant by the term “high level language”

Answer 1

• Written in a form that is close to our human language
• No knowledge of hardware/architecture required
• Portable - machine independent
• Examples: C#, Python etc.

Question 2

Explain what is meant by the term “low level language”

Answer 2

• Written in a form that is close to the processor instruction set
• Knowledge of hardware/architecture is required
• Not portable - machine dependent
• Examples: assembly language and machine code

Question 3

State 3 advantages of a high level language

Answer 3

• Easier to understand for programmers
• Portable - not machine specific
• No need to understand the architecture of a computer
• One instruction equals many processor instructions
• Much easier to debug and test
• Only need to learn a single language
• Has built in libraries and functions that can be reused

Question 4

State 3 advantages of a low level language

Answer 4

• Program often requires less memory/RAM
• Can make use of special hardware
• Can use memory addresses directly
• Can be written to run faster (optimised)

Question 5

Explain two reasons why a computer programmer may choose to write a program in a high- level language, rather than a low-level language.

Answer 5

• Closer to human language/English …
  
  • …so it is easier/quicker to read/write/understand/debug
• The program can be used on many different platforms…
  
  • …because it is compiled into object code
• They have built-in functions/libraries…
  
  • …this saves time when writing the program
• Do not need to manipulate memory addresses directly…
  
  • …therefore, specialist knowledge of this is not required
• Only need to learn a single language…
  
  • …as this can be used on many different computers

Question 6

Explain two reasons why a computer programmer may choose to write a program in a low-level language, rather than a high-level language.

Answer 6

• allows direct access to computer processor / special hardware //
• machine dependent instructions uses up less memory
• can increase the speed of processing a program // executes instructions faster

Question 7

State 3 different translators

Answer 7

• Assembler
• Compiler
• Interpreter

Question 8

State a translator that can be used to translate a low level language into machine code

Answer 8

• Assembler

Question 9

State 2 different translators that can be used to translate a high level language into machine code

Answer 9

• Compiler
• Interpreter

Question 10

Describe how an interpreter translates a computer program

Answer 10

• Translates high-level language into machine code
• Translates (the source code) line by line/statement by statement
• The interpeter is used each time the code is executed
• Stops if it finds an error and will only continue when error is fixed

Question 11

Describe how a compiler translates a computer program

Answer 11

• Translates high-level language into machine code (object code)
• Translates (the source code) all at once
• Produces an executable file
• Produces an error report / list of errors
• Optimises the source code (to run efficiently)

Question 12

Describe how an assembler translates a low level language

Answer 12

• Translates (the source code) all at once
• Produces an executable file
• Produces an error report / list of errors
• Optimises the source code (to run efficiently)

Question 13

Assembly language: True or False?

• Assembly language uses mnemonic codes.
• Assembly language programs do not need a translator to be executed.
• Assembly language is a low-level programming language.
• Assembly language is specific to the computer hardware.
• Assembly language is machine code.
• Assembly language is often used to create drivers for hardware.

Answer 13

• Assembly language uses mnemonic codes. TRUE
• Assembly language programs do not need a translator to be executed. FALSE
• Assembly language is a low-level programming language. TRUE
• Assembly language is specific to the computer hardware. TRUE
• Assembly language is machine code. FALSE
• Assembly language is often used to create drivers for hardware. TRUE

Question 14

Translator or Compiler?

• Translates the source code into machine code all at once
• Produces an executable file in machine code
• Executes a high-level language program one instruction at a time
• Once translated, the translator does not need to be present for the program to run
• An executable file is produced

Answer 14

Translator or Compiler?

• Translates the source code into machine code all at once Compiler
• Produces an executable file in machine code Compiler
• Executes a high-level language program one instruction at a time Interpreter
• Once translated, the translator does not need to be present for the program to run Compiler
• An executable file is produced Compiler

Question 15

Translator or Compiler?

• A report of errors is produced at the end of translation
• The program is translated one line at a time
• The program is translated from high-level language into machine code
• An executable file is produced
• The program will not run at all if an error is detected

Answer 15

Translator or Compiler?

• A report of errors is produced at the end of translation Compiler
• The program is translated one line at a time Interpreter
• The program is translated from high-level language into machine code Compiler & Interpreter
• An executable file is produced Compiler
• The program will not run at all if an error is detected Compiler

Question 16

Why might you use a compiler rather than an intrepreter?

Answer 16

• Compiled program can be executed without a translator
• Faster execution as it is not translated line by line
• Provides an executable file therefore you cannot see the code

Question 17

Why might you use an interpreter rather than an compiler?

Answer 17

• Faster for developing software and debugging …
  
  • all of the code does not need to be translated
  • can execute code quickly (line by line)