Hardware

by Spencer Tiberi

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 1
- 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

4	2	1
0	0	1

4	2	1
0	1	0

4	2	1
0	1	1

4	2	1
1	0	0

4	2	1
1	1	1

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

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, tablets, 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