Computer Systems - Translators

Question 1

What are the two types of computer languages?

Answer 1

High-level
Low-level

Question 2

What a high-level language?

Answer 2

A source code easy for humans to write but computers need to translate it before they can read it and run it

Question 3

What is a low-level language?

Answer 3

Tricky for humans to read but easier for a computer to run

Question 4

What do low-level languages consist of?

Answer 4

Machine code
Assembly code

Question 5

What is machine code?

Answer 5

Very tricky for humans to understand - each processor (or family of processors will have its own specific machine code

Question 6

What does machine code look like?

Answer 6

Binary - 000000 00001 00011…

Question 7

What is assembly code?

Answer 7

More readable for humans and easier to remember

Question 8

Why is it good if a code is easier to remember?

Answer 8

Programmers are less likely to make mistakes when wriitng assembly code than machine

Question 9

When is assembly code used?

Answer 9

When developing software for embedded systems and when programmers need more control over specific hardware

Question 10

What are the advantages of high-level languages?

Answer 10

The same code will work for many different machines and processors
The programmer can easily store data in lots of different structures (list and arrays) without knowing about the memory structure
Code is easy to read, understand and modify

Question 11

How many instructions of machine code is high-level code?

Answer 11

One instruction of high-level code represents many instructions of machine code

Question 12

What are the disadvantages of high-level language?

Answer 12

Must be translated before a computer is able to understand it
You don’t have much control over what the CPU actually does - programs will be less memory efficient and slower

Question 13

How many instructions of machine code is assembly code?

Answer 13

One instruction of assembly code usually represents one instruction of machine code

Question 14

What are the disadvantages of low-level code (machine code)?

Answer 14

Usually written for one type of machine/processor - won’t work on other
The programmer needs to know about the internal structure of the CPU - how it manages memory
Code is difficult to read, understand and modify

Question 15

What are the advantages of low-level code (machine code)?

Answer 15

Commands in this code can be executed directly without need of a translator
You control exactly hat the CPU does and how it uses memory - memory will be more memory efficient and faster

Question 16

What are the 3 types of translators?

Answer 16

Assemblers
Compilers
Interpreters

Question 17

What do assemblers do?

Answer 17

Translate assembly language directly into machine code - different types of assembly language needs its unique assembler

Question 18

What do compilers do?

Answer 18

Translate high-level code directly into machine code, and create an executable file

Question 19

What do interpreters do?

Answer 19

Take each instruction in the code and call machine code subroutines within their own code to carry out the instruction

Question 20

Why is a compiler bad for debugging?

Answer 20

It returns a list of errors for the entire program once compiling is complete

Question 21

Why is an interpreter good for debugging?

Answer 21

It will return the first error it finds and stop

Question 22

How fast is a compiler?

Answer 22

Once compiled, the program runs quickly - compiling can take a long time

Question 23

How fast is an interpreter?

Answer 23

It will run more slowly (than a compiler) because the code is being translated as the program is running

Question 24

How often are compilers needed?

Answer 24

Only needed once to create the executable file

Question 25

How often are interpreters needed!

Answer 25

Every time you want to run the program (bad)