History of OS

Question 1

Definition of OS

Answer 1

Software that manages a computer’s resources

Question 2

3 phases of hardware

Answer 2

1: hardware expensive, labor cheap
2: hardware cheap, labor expensive
3: hardware very cheap, labor very expensive

Question 3

First Computer (1945-1955)

Answer 3

Single user system, OS is a subroutine library and loader. It had one user on console and one process at a time. There was low utilization of expensive components.

Question 4

Batch Processing (1955-1965)

Answer 4

Load programs, run, output to tape, and then print results. Human acted as scheduler, running one job as another finished. However no protection and CPU is idle during I/O. This could execute/print/read batches of jobs at one time instead of just one at a time.

Question 5

Overlapping IO and Computation (1955-1965)

Answer 5

After batch processing, I/O and processing could happen concurrently.