1. W6D2

2. Software Computer (hardware) 1010 0110 1011 1100 1101 1111 0000 1010 0110 1010 1110 0001 Add 20,22,34

3. W6D2 Memory Magnetic core memory

4. W6D2 Memory (DRAM)

5. W6D2 Memory (DRAM)

6. W6D2 Software Computer (hardware) 1010 0110 1011 1100 1101 1111 0000 1010 0110 1010 1110 0001 Add 20,22,34

7. W6D2 Running programs Early computers: programs on perforated cards users installed tapes & cards… signup sheets!

8. W6D2 Running programs Things got a bit better: operator installed punch cards in batches (less time organizing, more computing time) a computer program controlled the execution of user programs (jobs) users had no direct interaction

9. W6D2 Running programs The PDP-1 operating system's timesharing ability made interactive access to computers economically viable by allowing various users to share the computer simultaneously. Shown here is the PDP-1 installation at BBN.

10. W6D2 Running programs System programs: Operating Systems User programs: Applications

11. W6D2 Hard disc IBM Disc Storage System (1961)

12. W6D2 Creating programs

13. W6D2 Source code

14. W6D2