2 - Brief History

Question 1

Two different ways to look at an OS

Answer 1

An extended machine

A resource manager

Question 2

Explain the concept of viewing an OS as an extended machine

Answer 2

Providing APIs to mask the ugliness of hardware
e.g., Working with files is easier than dealing
with raw disk space

Question 3

Explain the concept of viewing an OS as a resource manager

Answer 3

Resource Allocator

• In timer (e.g., 2 programs trying to print at the same time , two programs trying to run at the same time)
• In space (e.g., 2 programs trying to allocate memory)

Control program

• Control program execution
• Prevent error and improper use
• Handling all interrupts and traps

Question 4

When was the first OS invented?

Answer 4

IBM sold first computer with OS in the 1960s

Question 5

Describe the 1st generation OS.

Answer 5

Vacuum Tubes and no OS (1945 - 1955)

• Programs hardwired, then punch cards
• Written in machine language
• Only basic numerical calculations
• One application at a time

Question 6

Describe the 2nd generation OS.

Answer 6

Transistors and Batch Systems (1955 - 1965)

• Mainframe computers
• FORTRAN and COBOL programs on punch cards
• OSs -> FMS (Fortran Monitor System) and IBSYS (IBM’s OS)
• Batch sytems

Question 7

What is a batch system?

Answer 7

Batch processing is a technique in which an Operating System collects the programs and data together in a batch before processing starts.

In 2nd Gen OS, this was a physical batch of cards

Question 8

Describe the 3rd generation OS.

Answer 8

ICs and Multi-programming (1965 - 1980)

• Uses ICs
• OSes: IBM OS/360, CTSS (by MIT), MULTICS (complicated, but
  influential) , UNIX (inspired by MULTICS), and eventually Linux (90’s)
• Introduced concepts (multi-programming, spooling, time-sharing)

Question 9

What is multi-programming?

Answer 9

The computer can hold more than one program at a time.
A different job in each memory partition, CPU execute other
jobs while waiting for the I/O of some jobs

Question 10

What is spooling?

Answer 10

(Simultaneous Peripheral Operation On Line): read jobs from cards to
disk, load jobs from disk automatically, no more tapes

Used to deal with slow devices like printers

Basically a buffer that stands between fast and slow operations

Question 11

What is time-sharing?

Answer 11

multiple users using one computer simultaneously & interactively

Question 12

Describe the 4th generation OS.

Answer 12

Personal Computers (1980-present)

• Cheap mass produced computers
• User friendly shells on top of OS
• OSes: Windows, Mac OS, Linux + GNOME / KDE

Question 13

Describe the 5th generation OS

Answer 13

Mobile Computers (1990 - present)

Question 14

Which of the following concepts introduced interactive services for multiple users?
 A) Batch System
 B) Multi-programming
 C) Spooling
 D) Timesharing

Answer 14

Timesharing