Hardware

• Binary
• CPU
• RAM (Random Access Memory)
• Hard Drives
• Flash Memory
• Types of Memory and Funneling
• Display Connectors
• USB (Universal Serial Bus)
• Wireless
• Operating System (OS)
• Looking Underneath the Hood

Binary

• We use computers everyday
• Inside a computer are “0s and 1s”
  • Computers use the binary number system to represent info
    • How do computers represent info with just binary?
• Consider the decimal number (what we human typically use) 123
  • The rightmost column is the 1s column
  • The middle, the 10s

  • The leftmost, the 100s

    100	10	1
    1	2	3

  • Thus we have 100 x 1 + 10 x 2 + 1 x 3 = 100 + 20 + 3 = 123
• Inside a computer, the binary 000 would represent 0, just like in our human world!
  • However, in this case we are dealing with binary so:
    • The right most column is the 1s place
    • The middle, the 2s
    • The leftmost, the 4s

    4	2	1
    0	0	0

  • In the human world (decimal) we use powers of 10 for place values
    • 10⁰ = 1, 10¹ = 10, 10² = 100, 10³ = 1000, etc.
  • In the computer world (binary) we use powers of 2 for place values
    • 2⁰ = 1, 2¹ = 2, 2² = 4, 2³ = 8, etc.
  • The difference between decimal numbers and binary numbers is changing the base
  • For the binary number 000, we have 4 x 0 + 2 x 0 + 1 x 0 = 0 + 0 + 0 = 0!

• Consider the binary number 001:

  4	2	1
  0	0	0

  • We have 4 x 0 + 2 x 0 + 1 x 1 = 0 + 0 + 1 = 1
• How do we represent the decimal number 2 in binary?
  • We don’t need a 4, be we need a 2, and also no 1

  4	2	1
  0	1	0

  • This gives us 4 x 0 + 2 x 1 + 1 x 0 = 0 + 2 + 0 = 2

• Likewise, the number 3 would be:

  4	2	1
  0	1	1

  • As we need a 2 and a 1
  • Thus, 4 x 0 + 2 x 1 + 1 x 1 = 0 + 2 + 1 = 3

• Similarly, 4 would be:

  4	2	1
  1	0	0

• What about 7?

  4	2	1
  1	1	1

  • Which yields 4 x 1 + 2 x 1 + 1 x 1 = 4 + 2 + 1 = 7
• What about 8?
  • We can’t count to 8 without another bit (binary digit)
    • We run into this in the real world too if we need a four-digit number vs a 3-digit number
      • Start with the 1s, 10s, 100s place and add the 1000s
    • Here we’ll add the next power of 2, 8

    8	4	2	1
    1	0	0	0

    • 8 x 1 + 4 x 0 + 2 x 0 + 1 x 0 = 8
• Just like decimal numbers (base 10), numbers represent larger values on the left side and decrease as we move right.
• So if we wanted to compare the binary numbers 1001 and 1010 we could start on the far left side of the number and look for where the numbers differ. The one with a 1 will be larger than the one with a 0.

• Even though computers only use binary, they can count as high as humans can!
  • They do it with a smaller vocabulary, just 1 and 0.
    • This is because it’s easier to represent two states in the physical world
      • If you think of one of these bits as being a light bulb:
        • 0 is off
        • 1 is on
      • Light bulbs just need electricity to turn on or off
      • Electricity is sufficient to turn a switch on or off
        • Inside a computer exists these switches called transistors
          • Modern computers have billions!
          • Turned off represents 0
          • Turned on represents 1
• Using these transistors we can store values, store data, compute, and do everything we can with computers
• David demonstrates how transistors work using light bulbs
• So far all that we can represent is numbers
  • A decision needs to be made on what pattern of 1s and 0s to represent letters, words, and paragraphs
  • All computers can store is 0s and 1s
  • To represent letters, we need a mapping of 0s and 1s to characters
    • ASCII (American Standard Code for Information Interchange) does this

    

    • 65 -> A, 66 -> B, 67 -> C, etc.
    • 97 -> a, 98 -> b, 99 -> c, etc.
    • ASCII also has mapping for punctuation symbols
  • Programs like notepad, textedit, and MicroSoft Word decide weather to display patterns of bits as letters or words
    • Computers only store 0s and 1s, but the programs interpret those bits in a certain way
      • For example, if MicroSoft word sees a pattern of buts representing the number 65, it will interpret that as “A”
  • ASCII is limited
    • Original ASCII is 7 bits, thus giving 128 characters
      • Extended ASCII is 8 bits, yielding 256 characters
    • Many symbols are not represented
  • UNICODE is a bigger set of characters that includes written languages other than English and even emoji! 😲
    • All are still represented by a pattern of bits
• Consider this pattern of bits: 01001000 01001001
  • 16 bits or 2 bytes (1 byte = 8 bits)

  128	64	32	16	8	4	2	1		128	64	32	16	8	4	2	1
  0	1	0	0	1	0	0	0		0	1	0	0	1	0	0	1

  1 x 64 + 1 x 8	1 x 64 + 1 x 8 + 1 x 1
  72	73
  H	I

  • Using ASCII we get the word “HI”

CPU

• If you have heard that your computer has “Intel Inside,” it has an Intel processor in it

  

  • The backside of the processor has pins that connect into the motherboard
• The motherboard is a circuit board made of silicon
• The CPU is the brain of the computer
  • Does all the thinking
  • Performs math in numbers fed to it
  • Helps display numbers on a screen
  • Adds or deletes numbers
• CPUs now can have multiple cores
  • Cores are the devices inside the CPU that can preform mathematical operations, load info from memory, save info to memory, etc.
  • The more cores, the more tasks a CPU can do at once
• CPUs now also support hyper-threading
  • Where a single core will present itself as multiple cores to a computer’s operating system
• Systems on a Chip (SoaC) are when a CPU and more are all interconnected at once rather than attached to a motherboard
  • Popular in phones, tables, and game consoles

  • Raspberry Pi

    

RAM (Random Access Memory)

• Circuit board with chips that slides into a slot on the motherboard

  

  • The chips store data
    • Only stores data when the power is on
  • Files and programs are loaded onto these chips when ran
  • Fast memory

• You can check your RAM and other specs:

  • Windows Task Manager

    

    • CPU chart shows when peak usage occurs
    • GHz is the number of operations a CPU can perform per second (in billions)
      • 1.94 GHz = 1.94 billion operations per second
    • Logical processors in this case is 4, which means both cores support hyper-threading
      • Each core will do two things at once as if 4 cores exist

  • Mac System Profiler

    

Hard Drives

• When you turn a computer off, you need a place to store data

  • A hard disk drive (HDD) stores this information

    

  • RAM may store 1 GB, 2 GB, 4 GB, through 16 GB or so
  • HDD stores 256 GB, 1024 GB (AKA terabyte or TB), 2 TB

  • Inside a HDD, metal platters physically spin around

    

    • Data is stored on these disks
    • The reading heads move back and forth reading data from the device
    • Uses tiny magnetic particles where north pole orientation represents 1 and south pole orientation represents 0
      • Power is only needed to read or change the data
        • Data is preserved when power is off
    • David shows a video of a HDD running in slowmo
• To store data in a hard drive, RAM sends data and instructions to the HDD
  • The hard drive translates that data into voltage fluctuations
    • Some signals spin the platters, others move the read/write heads
    • Pulses sent to the read/write head turn on a magnet which creates a field that changes the polarity of a tiny portion of the metal platter’s surface
    • Power is sent in different directions as to change polarity
  • To read, the particles on the disk use their charge to move the read/write head.
  • Pieces of a file can be spread out around the platters
    • A special file keeps track of data’s location
  • Anytime you have a physical device that moves over a period of time, things go wrong
    • Dropping a HDD can corrupt files
  • Platters spin slower than how fast electrons move

Flash Memory

• Solid state disk (SSD)

  

  • Smaller (3.5 inch width for HDD vs 2.5 inch width for SSD)
    • Still fits where old HDDs are
  • No moving particles

  • Inside, it looks a lot like RAM

    

  • Much faster than HDD
    • Programs/files load and save more quickly
  • SSD theoretically don’t last as long as HDD
    • Finite number of writes
• Hybrid Drives
  • Some GB of solid state memory and more GB or TB of HDD space
  • Stores as much of frequently-needed data on the SSD
  • Stores less frequently-needed data on HDD
• Flash memory also exists in the form of USB sticks
  • Might store 1 GB, 16 GB, or more
  • Portable
• External SSDs exist for more storage
  • Might store 256 GB or more
  • Can be used to share data with others without network usage
• Can also have external HDD

Types of Memory and Funneling

• There is a tradeoff between space, money, and speed of data transfer

  

  • Data is pushed “down the funnel” to your CPU

    • From the hard drive, data first goes to the RAM

      

    • Theoretically, the CPU never has to wait for data to crunch
    • There is a tiny amount of memory (bytes) called registers where numbers are stored for operations.
    • Memory at the bottom is more expensive
    • Disk is important for the long-term storage
    • RAM is important as it stores programs you use simultaneously
    • L3, L2, L1 cache are on the motherboard
• As an analogy for memory, picture a candy store
  • A customer approaches the counter and requests candy
  • The shop owner then leaves the counter to grab the candy before returning moments later
    • Not super efficient to walk all the way to the store room to grab candy
      • Better to have a cache of memory
  • Instead, the shop owner leaves the counter to ready a cache of candy before the customers arrive
  • When a customer comes, the candy can be distributed quickly
    • Cache memory similarly helps the CPU in this manner
• We can see sizes of cache looking at computer specs like before

Display Connectors

• These sockets all connect to monitors or displays
• Mini DisplayPort are used form monitors
• HDMI is not only on laptops and computers but also TVs
• VGA is older, but still commonly uses on projectors

USB (Universal Serial Bus)

• Can plug in a whole range of peripheral devices including printers, keyboards, mice, scanners, etc.
• USB-A most common
• USB-B is often used for printers and scanners
• USB-C is newer and can be plugged in coming from different directions
• Other variants often exist for phones
• Older USB connections are slower when transferring data
  • Hard drives can connect via USB
    • Even if a hard drive is fast, if the USB is slow, the transfer of data will be slow

Wireless

• Wifi is wireless internet
• Bluetooth allows devices such as wireless keyboards and headphones to connect to your computer
  • Limited range
    • This is ok as it is used for you to connect to your own device

Operating System (OS)

• Software that ensures all devices work and can intercommunicate
• MacOS and Windows are popular OS
• Can be installed by the user, but is typically done so by a manufacturer
  • Installed on HDD or SDD so that it exists persistently without power
• When you hit power on your computer, the OS is loaded into RAM
• Gives you the graphical interface that you see
• Knows how to:
  • Talk to your keyboard and mouse
  • Display info on the screen
  • Move things around in memory
• This is all thanks to device drivers installed with the OS
  • Special software designed to talk to certain model of printer, camera, scanner, etc.
• When an OS doesn’t recognize a device, perhaps because it’s too new, you can download new device drives from the device manufacturer
  • Teaches Window, MacOS, or Linux about that new hardware
  • Future-proofing structure
• It’s this intersection of hardware and software that makes computers powerful!

Looking Underneath the Hood

• David and Colton Ogden look at the exterior of an old ThinkPad computer, examining ports
  • Power bricks convert power from the wall into safe amounts for the computer
• David and Colton examine the inside of an old window desktop, highlighting the motherboard, heatsink, RAM, Hard Drive, etc.
• David and Colton then look inside a HDD
  • Once exposed to air and dust, it’s no longer reliable enough to use
• David and Colton then look at a motherboard examining all the ports on it