User interfaces

Question 1

Why is UI important ?

Answer 1

It is a crucial link for the human-computer interface (HCI). It facilitates the communication with system components.

Question 2

What are the classes of users ?

Answer 2

Programmers, Operational Users, End-Users

Question 3

What are the different types of interfaces ?

Answer 3

System call, Command language, Job Control, Graphical User

Question 4

What are system calls ?

Answer 4

Similar to functions but exist at the OS kernel level. High rank API’s can invoke system calls without direct interaction.

Question 5

How are system calls structured in UNIX / LINUX

Answer 5

defined as C functions in a one-to-one mapping. Examples are: file management, process management

Question 6

How are system calls structured in Windows ?

Answer 6

Windows uses the Win32 API instead of direct one to one mapping. Thousands of APIs exist, some interacting with system calls and some user-space operations.

Question 7

What is a command language interface ?

Answer 7

Used for direct communication with the OS, mainly used by operational users.

Question 8

What is a job control interface ?

Answer 8

Automates job execution with minimal user intervention. Used in batch processesing on mainframes.

Question 9

What is the WIMP model of GUI ?

Answer 9

Windows, Icons, Menus, Pointer

Question 10

What is the X Window system ?

Answer 10

A common GUI for UNIX like systems. Uses a client-server model

Question 11

Why is GUI good for most users ?

Answer 11

Provides many built in tools for programmers and displays things in a simplified, user-friendly enviroment for basic users.