Discussion of exam problems

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1 Discussion of exam problems 1

2 Hint for Homework problem 72: Show how to connect three Full Adders to implement a 2-bit ripplecarry adder 2

3 C D A B Connect to ground (0) Z X Y 3

4 Chapter 5 Computing Components Yet another layer of abstraction! Components Circuits Gates Transistors

5 5.1 Individual Computer Components Consider the following ad: Insatavialion 640 Laptop Exceptional Performance and Portability! It s just a madeup example! 5

6 6 What does all this jargon mean? Intel Core 2 Duo (2.66GHz/1066Mhz FSB/6MB cache) 4GB Shared Dual Channel DDR2 at 800 MHz 500 GB SATA Hard Drive at 5400RPM 15.6 High Definition (1080p) LED Backlit LCD Display (1366 x 768) 8X Slot Load DL DVD+/- RW Drive 14.8 W X 1.2 H X10.1 D, 5.6 lbs. 512 MB ATI Mobility Radeon Graphics 85 WHr Lithium Ion Battery Be patient! You don't know them now, but you will get used to them. (2) USB 2.0, HDMI, 15-Pin VGA, Ethernet 10/100/1000 IEEE 1394 Firewire, Express Card, Audio line-in, line-out, mic-in

7 Multipliers When referring to computer memory, mega does not mean one million! (but it s still close to that) 7

8 Decimal vs. binary multipliers 1000 = ,000,000 = ,000,000,000 = = *1024 = *1024*1024 = 2 30 Rule: For memory capacities, the multipliers are binary, for everything else (speed, frequency, pixels, etc.) they are decimal 8

9 Decimal vs. binary multipliers examples What is the meaning of: 1.5 TB hard-disk 54 Mbps wireless Ethernet 6 GB of RAM 8 Mega-pixel camera 3.2 GHz CPU 9

10 Intel Core 2 Duo (2.66GHz/1066Mhz, FSB/6MB cache) 10

11 QUIZ: A CPU chip is rated 2.5 GHz. What is the duration of one clock cycle? Use appropriate units! 11

12 QUIZ: A CPU chip is rated 2.5 GHz. What is the duration of one clock cycle? Use appropriate units! Solution: Hz = frequency = f = = 1/(duration of one CLK cycle) = 1/T T = 1/f = 1/ s = 0.4 ns 12

13 Quick work for next time: A CPU chip is rated 3.44 GHz. What is the duration of one clock cycle? Use appropriate units! 13

14 5.2 Stored-Program Concept The von Neumann (a.k.a. Princeton) architecture is based on two fundamental ideas: 1. Instructions and data are the same, so they are stored in the same circuit (memory) 2. Information processing is different from information storage, so they are performed in different circuits (CPU, memory) 14

15 Not in text Are there any other architectures? The Harvard architecture is based on two fundamental ideas: 1. Instructions and data are not the same, so they are stored in separate circuits (memories) 2. Information processing is different from information storage, so they are performed in different circuits (CPU, memory) Image source: 15

16 QUIZ: Which of the diagrams depicts a von Neumann architecture? 16

17 QUIZ: Which of the diagrams depicts a von Neumann architecture? 17

18 Main Memory (MM) Remember that in the vn architecture there is only one MM, which stores both data and programs! 18

19 Main Memory Blades Which hardware layer does memory belong to? Components Circuits Gates Transistors Image sources:

20 Main Memory = A collection of cells, each with a unique physical address Both addresses and contents are in Binary (or hex) Cells can be bits, nibbles, bytes, words

21 The address and contents of a memory cell are the following, in hex: QUIZ 89AB FC Translate them into decimal and binary.

22 Addressability = the # of bits in each cell What is the addressability of the memory pictured? Today, most computers memories are byteaddressable

23 QUIZ 1. How many bytes of memory are in the MM pictured? 2. Express the result using the appropriate multiplier.

24 QUIZ 1. How many bits does the address have in this memory? 2. What is the addressability? 0x789ABCDE 0x789A EOHF1

25 QUIZ: Connect each hardware item to the layer it belongs to: mouse XOR Intel 8008 NTE 2996 MOSFET MUX motherboard full adder SR latch Components Circuits Gates Transistors

26 QUIZ: A CPU s frequency is 12 KHz. What is the duration of one clock cycle? Use appropriate units! 26

27 QUIZ: A CPU s clock cycle is 55 ns. What is the frequency? Use appropriate units! 27

28 ALU 28

29 ALU basic arithmetic operations such as add, subtract, increment, decrement, change sign, multiply, integer division logical operations such as AND, OR, XOR, NOT 29

quickly (in one CLK cycle), w/o waiting for a lengthy (~10

30 The ALU also has a few very fast storage units called registers The information in a register can be processed quickly (in one CLK cycle), w/o waiting for a lengthy (~10 ns) memory transfer. Figure source: 30

31 Input/Output devices The von Neumann architecture 31

32 Input/Output devices Input device A device through which data and programs from the outside world are entered into the computer; Can you name three? Output device A device through which results stored in the computer memory are made available to the outside world Can you name three? 32

33 Control Unit The von Neumann architecture 33

Control Unit It is the organizing force in the computer Implements the fetch-execute cycle Includes two important registers: Instruction register (IR)

34 Control Unit It is the organizing force in the computer Implements the fetch-execute cycle Includes two important registers: Instruction register (IR) Contains the instruction that is being executed Program counter (PC) Contains the address of the next instruction to be executed ALU + Control Unit = CPU 34

35 Flow of Information Bus = A set of wires that connect all major units in a computer Data flow through a von Neumann architecture 35

36 Flow of Information Bus = A set of wires that connect all major units in a computer Data flow through a von Neumann architecture How can we tell that it s a vn architecture? 36

37 Flow of Information Bus = A set of wires that connect all major units in a computer Is there another kind of memory? 37

38 Cache FSB and BSB Back-side Bus (BSB) Front-side Bus (FSB) Note: Although the CPU can access two memory circuits, this is still considered a vn architecture, b/c the cache is much smaller than the MM. 38

39 Find the info about bus and cache in the ad! 39

40 The Fetch-Execute Cycle Fetch the next instruction Decode the instruction Get data (if needed) Execute the instruction Remember: In a vn machine, both instructions and data are stored in the same memory! Why is it called a cycle? 40

41 The Fetch-Execute Cycle Read carefully pp of text! 41

42 RAM and ROM The memory used for the main memory (MM) of a computer is of 2 types: RAM and ROM Both can be accessed directly, i.e. in constant time, by providing a memory address. Both can be read. However, when it comes to writing

43 RAM and ROM Random Access Memory (RAM): can be changed (written) is volatile Read Only Memory (ROM): cannot be changed (written) is not volatile Take this with a grain of salt: Today s ROMs can be written, just not as fast as RAMs.

44 Secondary Storage The size of the MM (RAM+ROM) in today s computers ranges between The amounts of data we need to store are much larger! Example: Youtube video clips 20 GB Secondary storage is a.k.a. mass/volume/bulk storage. 44

45 Secondary Storage technologies Magnetic: drum, tape, floppy disk, hard disk (internal or external) Semiconductors: flash drive, SD card Optical: CD-R (WORM=Write Once Read Many times), DVD-R, DVD-R DL, Blue-Ray Emerging: spintronics (MRAM), Ferroelectric RAM, DNA storage, etc. 45

46 Other benefits of Secondary Storage Portability Reliability (backups) Modularity (add as you go) 46

47 The first truly mass storage device was the magnetic tape drive Tape drives have a major problem; can you spot it? Magnetic Tape Figure 5.4 A magnetic tape

The first high-volume auxiliary storage device was

48 The first high-volume auxiliary storage device was the magnetic tape drive Image sources:

49 Magnetic Disk - HDD Platter Amount of information (bits, bytes) is the same on all tracks Disc rotates at the same angular velocity no matter which track is being read same transfer rate on all tracks! Tracks near center are more densely packed with information

50 QUIZ: HDD A HDD has 512 Bytes/sector, 256 sectors/track, and 10 platters. The diameter of each platter is 100 mm, and each track is 1 mm wide. Calculate the total capacity of the drive in MB. Use binary Mega!

51 Solution 125 MB A HDD has 512 Bytes/sector, 256 sectors/track, and 10 platters. The diameter of each platter is 100 mm, and each track is 1 mm wide. Calculate the total capacity of the drive in MB.

52 Seek time Time it takes for read/write head to be over right track Latency Time it takes for sector to be in position under R/W head Access time = Seek time + latency Transfer rate (e.g. 100 MB/s) 52

53 QUIZ: HDD The arm of a HDD moves at an average velocity of 40 m/s. The platter diameter is 100 mm. What are the minimum and maximum possible seek times? Calculate the average seek time. 53

54 Solution 1.25 ms The arm of a HDD moves at an average velocity of 40 m/s. The platter diameter is 100 mm. What are the minimum and maximum possible seek times? Calculate the average seek time. 54

55 QUIZ: HDD The spindle of a HDD rotates at 7200 RPM. What are the minimum and maximum possible latencies? Calculate the average latency. 55

56 Solution The spindle of a HDD rotates at 7200 RPM. What are the minimum and maximum possible latencies? Calculate the average latency ms 56

57 QUIZ: HDD If the previous 2 quizzes refer to the same HDD, what is its average access time? 57

58 Solution If the previous 2 quizzes refer to the same HDD, what is its average access time? 4.16 ms ms = 5.41 ms 58

59 QUIZ: HDD A file is on the HDD, on 15 consecutive blocks of the same track. Each block stores 4 KB. Average seek time = 10 ms, average latency = 5 ms. Once the first block is under the head, data is transferred at a rate of 50 MB/s. Calculate the total time needed to transfer the file. 59

60 Solution A file is on the HDD, on 15 consecutive blocks of the same track. Each block stores 4 KB. Average seek time = 10 ms, average latency = 5 ms. Once the first block is under the head, data is transferred at a rate of 50 MB/s. Total time needed to transfer the file: ms 60

61 Source: 61

62 Quick Work for next time Read text pages Solve exercises EoHW2 62

63 QUIZ: Computer Components Explain in your own words the functions of the following components: ALU Control Unit Input device Main Memory Cache 63

64 What do the acronyms FSB and BSB stand for? Compare and contrast them. 64

65 What do the acronyms FSB and BSB stand for? Compare and contrast them. 65

66 Magnetic Disks - Removable Floppy disks (Why "floppy"?) Year when they first became commercially available: 1969 (8-inch) 1976 (5¼-inch) KB 87 KB-1.2 MB 1982 (3½-inch) 1.44 MB 66

67 Magnetic Disks - Removable Zip disks Iomega, MB, 250 MB, 750 MB 67

68 Flash memory IBM 1998 Nonvolatile! Can be erased and rewritten But there s a rub: Flash Endurance No moving parts! Thumb drives Solid State Drives (SSD) 68

69 To do in notebook for next time: Calculate the cost per gigabyte for HDD and SDD Source: October

70 Optical Disks CD (600 MB) A compact disk that uses a laser to read information stored optically on a plastic disk; data is evenly distributed around track CD-ROM read-only memory CD-DA digital audio CD-WORM or CD-R user can write once, read many times CD-RAM or CD-RW user can both write and read many times DVD (4.7 GB) Digital Versatile Disk, used for storing audio and video DL = dual layer 8.5 GB Blu-Ray (25 GB) DL = dual layer 50 GB 70

71 Your turn! How many songs can be stored on each type of optical disk? CD (600 MB) DVD (4.7 GB) Blu-Ray (25 GB) Hints: The average MP3 file is 4 MB. Use binary multipliers! 71

72 Solution How many songs can be stored on each type of optical disk? CD (600 MB) DVD (4.7 GB) Blu-Ray (25 GB) Hints: The average MP3 file is 4 MB. Use binary multipliers! 72

73 Interesting difference between magnetic and optical drives/disks: On a magnetic disk, each track has the same amount on data, there is no accounting for length (center or periphery). The limiting track is the innermost one! On an optical disk, data is uniformly packed per sector length Short tracks (near the center) have less data than long tracks (near the periphery). In a HDD, the speed of rotation is constant, but in an optical drive rotation is faster on the inner tracks, resulting in Constant Linear Velocity (CLV) 73

74 Read and take notes: Touch Screens 74

75 5.3 Embedded Systems Computers that are dedicated to perform a narrow range of functions as part of a larger system. Every computer that doesn t have a normal display and keyboard How many embedded systems do you think are in this room? 75

76 Embedded systems are everywhere today! communications automotive military medical consumer/home machine control (CNC) robotics entertainment Source: Source: www/ethio-civility.com 76

77 5.4 Parallel Architectures Remember that a vn architecture has one main memory and one CPU. There are two ways to evolve into nonvn architectures: 1. Multiple main memories (Harward arch.) 2. Multiple CPUs, a.k.a. parallel arch. 77

78 Parallel Arch.: Synchronous processing One approach to parallelism is to have multiple processors apply the same program to multiple data sets: Figure 5.8 Processors in a synchronous computing environment 78

79 Not in text Synchronous processing example: GPU = Graphics Processing Unit It was invented by NVIDIA in Image source:

80 Parallel Arch.: Pipelining Processors are arranged in tandem, with each processor contributing one part to an overall computation Figure 5.9 Processors in a pipeline 80

81 Not in text Washer-dryer analogy 81

82 Not in text Train analogy 82

83 Find the # of steps in terms of n and k n k Hint: Concentrate on the last car! # of steps is n+k-1 83

84 QUIZ Pipelining A computer pipeline has 3 stages, as shown above. Each stage takes 8 ms to execute, and each instruction must go sequentially through all 3 stages. A program has 5 instructions. Calculate how long it takes to run it: without pipelining with pipelining 84

communicate through shared memory Unlike synchronous processing, there

85 Parallel Arch.: Parallel Processor It s made of a number of vn processors which communicate through shared memory Unlike synchronous processing, there is no central control. Each CPU participates in a distributed control protocol! 85 Figure 5.10 Shared memory configuration of processors

86 Quick-work for next time: Read pp of our text and take notes Answer end-of-chapter questions 30-38, Homework: 39, 40, 41, 48, 49, 54, 56, 63, 64, 66 Due Tuesday, Oct.23 at beginning of class 86

Show how to connect three Full Adders to implement a 3-bit ripple-carry adder

Show how to connect three Full Adders to implement a 3-bit ripple-carry adder 1 Reg. A Reg. B Reg. Sum 2 Chapter 5 Computing Components Yet another layer of abstraction! Components Circuits Gates Transistors