Computer Abstractions and Technology

1
Computer Abstractions and Technology

• Looking up
• assemblers, compilers, programs
• Looking down
• input devices (mouse, keyboard)
• output devices (VDT, printer)
• storage devices (memory, hard drive, ZIP drive)
• processor

2
Machine Code

• Instructions that control the actions of the
  processor
• Instruction Set
• Vocabulary of commands understood by a certain
  architecture
• Instruction Set Architecture
• Abstract interface between hardware and lowest
  level of software

3
Computer Program Abstraction

• High-level language program compiled into

• Assembly language program(processor-dependent) a
  ssembled into

• Binary machine code program(processor-dependent)
  

4
Programming Languages

• Advantages
• more natural for reasoning about programs
• improved productivity
• easier to write programs at higher abstraction
  level
• independent of computer processor

5
Program LibrariesOperating Systems

• Program libraries
• Promote reuse
• Avoid having to write from scratch each time
• Operating System
• Supervisor program (safer) managing system and
  application (user, less safe) programs

6
Computer Organization

• Classic components of a computer
• Input
• Output
• Memory
• Datapath
• Control

7
Computer Organization

• Classic components of a computer
• Input
• Output
• Memory
• Processor (Datapath Control)

8
Memory Hierarchy

• Primary (main) memory
• fast (50-100ns access time), small, volatile
• solid-state, no moving parts
• implemented with DRAMs (since 1975)
• Secondary memory
• slower (5-20ms access time), larger, cheaper,
  persistent
• mechanical
• implemented with magnetic disks (since 1965)

9
Road Map

• Input (Chapter 8)
• Output (Chapter 8)
• Memory (Chapter 7)
• Datapath (Chapters 4, 5, 6)
• Control (Chapters 5, 6)

10
Also in Chapter 1

• 1.5 Real Stuff Manufacturing Pentium Chips
• 1.6 Fallacies and Pitfalls
• 1.8 Historical Perspective and Related Reading
• 1.9 Key Terms