CSCI 447 Operating Systems Filip Jagodzinski

Transcription

1 Filip Jagodzinski

2 Announcements Lab 1 This Monday, in CF420 during lecture time git, kpl, blitz, etc. primer PRIOR to the lab, please read the 7 page blitz overview document available on the course website

3 Announcements Lab 1 This Monday, in CF420 during lecture time git, kpl, blitz, etc. primer PRIOR to the lab, please read the 7 page blitz overview document available on the course website Reminders Do the recommended readings The lecture slides complement and not supplement the recommended readings

4 ABCD Cards

5 In-class exercise

6 Today Introduction / Architecture Review (Chapter 1 of textbook)

7 Computer Systems Computer Hardware Task : Enumerate several computer hardware components

8 Computer Systems Computer Hardware CPU Memory I/O devices Registers Buffers bus

9 Computer Systems Operating System Computer Hardware Controls the hardware and coordinates its use

10 Computer Systems Programs / Software : tools for solving problems gcc emacs atom Chromium Programs DB Operating System Computer Hardware

11 Computer Systems Programs / Software : tools for solving problems Q: What problem does Chromium solve? gcc emacs atom Chromium Programs DB Operating System Computer Hardware

12 Computer Systems user A single user of a system may be at any one time running a single program gcc emacs atom Chromium Programs DB Operating System Computer Hardware

13 Computer Systems user Or may be running multiple programs gcc emacs atom Chromium Programs DB Operating System Computer Hardware

14 Computer Systems user user user user gcc emacs atom Chromium Programs DB Operating System Computer Hardware

15 Computer Systems user User View : The OS is that thing that provides/orchestrates the use of resources to get stuff done gcc emacs atom Chromium DB Programs Operating System Computer Hardware

16 Computer Systems user gcc emacs atom Chromium Programs DB Operating System Computer Hardware Q: What problem does the OS solve in this context? System View : The OS is a resource manager/allocator

17 Computer Systems user user user user gcc emacs atom Chromium Programs DB Operating System Computer Hardware OS : solves the problem of resource allocation System View : The OS is a resource manager/allocator

18 Computer Systems Q: What is the kernel? gcc emacs atom Chromium Programs DB Operating System Computer Hardware

19 Computer Systems Q: What is the kernel? Device Computer Hardware CPU Controller Controller adapters Device memory Device

20 Computer Systems Q: What is the kernel? Task : Give examples of Devices Q: What is the role of an adapter or controller? Q: How does a controller/adapter work? Device Computer Hardware CPU Controller Controller adapters Device memory Device

21 Computer Systems Q: What is the kernel? Always running Listening for events (interrupts) Policies for Transferring Control CPU Controller Controller adapters Device Device memory Device

22 Computer Systems Q: What is the kernel? Polices for fair/secure/efficient utilization of available resources user user user user CPU Controller Controller adapters Device gcc emacs atom Chromium DB Programs Device Operating System Computer Hardware memory Device

23 Computer Systems Q: What is the kernel? Q: Where does the kernel live? Q: Where is it stored/saved? user user user user CPU Controller Controller adapters Device gcc emacs atom Chromium DB Programs Device Operating System Computer Hardware memory Device

24 Computer Systems Q: What is the kernel? Q: Where does the kernel live? Q: Where is it stored/saved? user user user user gcc emacs atom Chromium Programs DB Operating System Device Computer Hardware Device CPU Controller Controller Device adapters memory ROM, EEPROM (firmware)

25 Program Execution Von Neumann architecture

26 Program Execution Arithmetic and Logical Units Instruction (input) Result (output) Control Until Unit

27 Program Execution Q: What is software? Q: What are the major components of a computer? Q: How are they related?

28 Program Execution Q: What is software? Q: What are the major components of a computer? Q: How are they related? A computer program is a set of instructions for moving around data (1s and 0s), and a computer s major components are the hardware that allow that moving to occur

29 Program Execution

30 Program Execution Zooming in on the CPU, I/O Module, and main memory all of which is connected by a bus

31 Program Execution Zooming in on the CPU, I/O Module, and main memory all of which is connected by a bus Q: What are these digits?

32 Program Execution Zooming in on the CPU, I/O Module, and main memory all of which is connected by a bus Q: What are these digits? The addresses (unique identifiers) of locations in memory that contains data as either an instruction or data Memory addresses are usually labelled (have IDs) made up of hexadecimal addressing (but for simplicity we can refer to the addresses as decimal)

33 Program Execution Q: How is data (instructions and/or data) moved about among the different components to run a program

34 Program Execution Q: How is data (instructions and/or data) moved about among the different components to run a program In its simplest form, processing (or running) a computer program is done via a fetch-execute cycle Fetch : Read instructions one-at-a-time Execute : Perform the operation specified by each instruction

35 Program Execution Q: How is data (instructions and/or data) moved about among the different components to run a program The processor fetches an instruction from memory The program counter (PC) holds the address of the instruction to be fetched next The processor increments the PC after each instruction fetch so that it will fetch the next instruction in sequence The fetched instruction is loaded into the instruction register (IR) The processor interprets the instruction and performs the required action

36 Program Execution Q: What do the acronyms PC and IR refer to? Q: How is data (instructions and/or data) moved about among the different components to run a program The processor fetches an instruction from memory The program counter (PC) holds the address of the instruction to be fetched next The processor increments the PC after each instruction fetch so that it will fetch the next instruction in sequence The fetched instruction is loaded into the instruction register (IR) The processor interprets the instruction and performs the required action

37 Program Execution Q: How is data (instructions and/or data) moved about among the different components to run a program Q: What does it mean to execute an instruction

38 Program Execution A concrete example. But first, a question: Q: What does hexadecimal mean?

39 Program Execution Hexa :? A concrete example. But first, a question: Q: What does hexadecimal mean?

40 Program Execution A concrete example. But first, a question: Q: What does hexadecimal mean? Hexa : 16 The alphabet for binary is {0,1}. What is the alphabet for hexadecimal (hex)?

41 Program Execution A concrete example. But first, a question: Q: What does hexadecimal mean? Hexa : 16 The alphabet for binary is {0,1}. What is the alphabet for hexadecimal (hex)? {0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F}

42 Program Execution Assume you ve written a program that has been compiled and saved as an executable in memory. Using the OP codes shown left, and PC and memory data shown above, what does the program do?

43 Program Execution

44 Program Execution

45 Program Execution

46 Program Execution

47 Program Execution Q: How is this program executed by the computer? Q: How is

48 Program Execution The PC contains 300, the address of the first instruction. That s what the computer executes

49 Program Execution The PC contains 300, the a the first instruction. That s The PC contains 300, the address computer of the first execute instruction. That s what the computer executes This instruction (the value 1940 in hexadecimal) is loaded into the instruction register IR, and the PC is incremented (shown in next step). Q: What happens next?

50 Program Execution The PC contains 300, the a the first instruction. That s The PC contains 300, the address computer of the first execute instruction. That s what the computer executes This instruction (the value 1940 in hexadecimal) is loaded into the instruction register IR, and the PC is incremented (shown in next step).

51 Program Execution The first 4 bits (first hexadecimal digit) in the IR indicates that the AC should be loaded. The remaining 12 bits (three hexadecimal digits) specify the address (940) from which data is loaded. The data is transferred.

52 Program Execution Q: What happens next? Q: What hap

53 Program Execution Q: What happens next? Q: What hap The execute cycle has just completed, so next up fetch the next instruction Q: How does the computer know which instruction to fetch?

54 Program Execution Q: What happens next? Q: What hap The program counter (which was incremented) specifies which next instruction to fetch.

55 Program Execution Q: What hap The next instruction Q: (5941) What is hap fetched from location 301, and the PC is incremented (shown next step) Q: What happens next?

56 Program Execution Q: What hap Q: What hap

57 Program Execution Q: What happens next? Q: What hap Q: What hap

58 Program Execution Q: What happens next? Q: What hap Q: What hap The execute cycle has just completed, so next up fetch the next instruction How does the computer know which instruction to fetch?

59 Program Execution Q: What hap Q: What hap Q: What does instruction 2941 decode do?

60 Program Execution This program encoded using the instruction set adds 2 numbers saved already in memory, and updates an existing variable what is possible pseudocode for this instruction?

61 Program Execution This program encoded using the instruction set adds 2 numbers saved already in memory, and updates an existing variable what is possible pseudocode for this instruction? y = 3 x = 2 y = y + x

62 Memory Hierarchy Q: What is the memory hierarchy?

63 Memory Hierarchy Q: What is the memory hierarchy? Q: What are the consequences/properties of the memory hierarchy?

64 Memory Hierarchy Q: What is the memory hierarchy? Q: Assuming a cache (L1 and L2 combined) size of x, a program of size of y, and data of size z used by program y, which of the following architectures will permit program z to be the fastest, and why? (assume no other program are running) A. x=2mb, y=1mb, z=3mb B. x=1mb, y=2mb, z=3mb C. x=1mb, y=3mb, z=2mb D. x=3mb, y=1mb, z=2mb

65 I/O requests data interrupts Putting it all together from the book CPU/cache data instructions instructions data Memory Devices

66 I/O requests data interrupts Putting it all together Q: Where is the OS in all this? Q: Which of these labels is referring to the OS? CPU/cache data instructions instructions data Memory Devices

67 I/O requests data interrupts Operating System Operations what the OS does Q: Where is the OS in all this? Q: Which of these labels is referring to the OS? CPU/cache data instructions instructions data Memory Interrupts Devices

68 I/O requests data interrupts Operating System Operations what the OS does Q: Where is the OS in all this? Q: Which of these labels is referring to the OS? CPU/cache data instructions instructions data Memory Devices Interrupts Mechanism (agreed-up mode) of waiting and passing of control to enable movement and processing of data

69 User and kernel modes time user kernel Mode bit : 0 / 1

70 User and kernel modes time user A process kernel Mode bit : 0 / 1

71 User and kernel modes time user A process System call kernel Mode bit : 0 / 1

72 User and kernel modes time user A process System call kernel Execute system call Mode bit : 0 / 1

73 User and kernel modes time user A process System call Return from system call kernel Execute system call Mode bit : 0 / 1

74 Up Next Process Management Memory Management Storage Management Protection/Security Kernel Data structures OS structures (Chapter 2)