Week 1: Introduction to IT

What's the highest value we can represent in an individual byte?

255. We can represent 0-255

What is the binary system?

A base-2 numeral system, used by computers to communicate. It only has 1s and 0s, which can be grouped together to represent letters and words.

What is a computer?

A device that stores and processes data by doing calculations.

What is a byte?

A group of 8 bits.

What is an algorithm?

A series of steps that solve specific problems.

How many numbers can we represent using bits?

ALL OF THEM!

Where did the term debugging come from?

Admiral Grace Hopper's team of engineers, and the infamous moth found in one of their vacuum tubes.

Who invented the first compiler?

Admiral Grace Hopper.

Who was Alan Turing?

An English mathematician and computer scientist. He helped develop the Enigma machine to decode messages in WWII.

Who was Charles Babbage?

An engineer who built a "difference engine." It was a more sophisticated version of Pascal's mechanical calculator.

Who was Steve Wozniak?

An engineer. He invented Apple 1 and 2. Along with Steve Jobs, he created Apple.

What is Unix?

An operating system developed by Ken Thompson and Dennis Ritchie.

What is character encoding?

Assigning binary values to human-readable data.

What will be covered in this course?

Basics about computers: How they work, how they make calculations, how to build one, operating systems, the internet (i.e., how computers talk to each other), software applications, and troubleshooting.

How can we represent so many characters -- including emojis -- with only 256 possible values, in a byte?

By using character encoding.

What does a computer do?

Calculations. Billions of times per second.

What's an example of abstraction?

Driving a car. 2 different brands of cars could have completely different internals. But, they both have brakes, steering wheel, etc. and you operate it the same way. A more technical example would be an error message.

We talk about 1s and 0s in the abstract. But what are they physically for a computer?

Electric signals, inside of transistors, that are either on (1) or off (0).

What does an IT support specialist do?

Ensure that an organization's technology is up and running.

What was the analytical engine?

Follow-up to Babbage's difference engine. It used mechanical parts that helped it calculate manually instead of automatically, and could be programmed using a punch card. It became the first general computing machine in history, in part due to Lovelace's discovery of the algorithm.

Why do we use 8 bits specifically?

For historical reasons: hardware used to use the base-2 numeral system to move things around. And 2^8 numbers offers a big enough range to use.

How was the 20th century for computing?

Good. Big companies like IBM were making a lot of progress, and the government was investing a lot in computers. At around the 1950s, magnetic tape began to replace cards, because it allowed for more data storage. Vinyl records and cassette tapes are examples of this. Computers at this time were still huge, taking up entire rooms. And vacuum tubes kept track of electric currents.

What are the 4 layers of computer architecture?

Hardware, operating system, software, and users.

What's an important piece of advice for the IT field?

Have STRONG FUNDAMENTALS! And don't forget them.

What did the programmer Richard Stallman do?

He started developing a free, Unix-like operating system called GNU. It was open-source, and not a full operating system. It paved the way for Linux in the future.

Why do we use QWERTY keyboards?

Historically, typists needed to be slowed down in order to avoid jamming of the keys. Additionally, it might have been helpful for telegraph operators. No one is completely sure of the real reason; however, QWERTY isn't actually the most efficient type of keyboard.

What is the software layer of computer architecture?

How we as users interact with the computer.

How did video games get their start?

In the 1970s and 80s, with arcades. Atari, in 1972, created the arcade game Pong. After that, with the Video Computer System, Atari brought games into the home. This was important because it showed that computers could be fun, and used for fun.

What did IBM do for the history of computing?

In the 1980s, they released PCs with an operating system called MSDOS, or Microsoft Disk OS. They also worked with Bill Gates to develop Windows.

How is binary grouped?

Into groups of 8 numbers, called bits (binary digits).

What is a mechanical calculator?

Invented by Blaise Pascal in the 17th century. Used gears and levels to do automatic calculations, but was limited to simple operations (add, subtract, multiply, divide) for small numbers.

What is the operating system layer of computer architecture?

It allows hardware to communicate with the software system. It also serves as a layer of abstraction: the same set of hardware can often run different operating systems. Mac hardware can run Windows and Linux, for example.

What is the user layer of computer architecture?

It consists of the person who interacts with the computer, and is the most important part of IT.

Name an advantage of Unicode.

It helps us represent character encodings in a consistent manner.

Who made Linux?

Linus Torvalds

What is a loom, and how does it relate to computing?

Looms are used for weaving thread/yarn into fabric. Joseph Picard made a programmable one. It was used for weaving designs and patterns into textiles. It used punch cards, and would only thread if it saw a hole.

What is UTF-8?

Most prevalent encoding standard used today, built off of Unicode (which is just a set of characters; UTF-8 is the implementation of Unicode in binary). It uses the standard ASCII table, but it also uses a variable number of bytes. So at least theoretically, we can have an unlimited amount of characters.

Who made the first smartphone?

Nokia, in the late 90s, made a PDA with a phone built in, which was the first smartphone.

What do bytes store?

One character, with 256 possible values (2^8).

What is an abacus?

One of the first computers, from around 500 B.C. and still in use today.

What was the ENIAC?

One of the first forms of general purpose computers.

What are PDAs?

Personal digital assistants. An example of how small computers we're getting at the time: you could do a lot of stuff with just 1 device.

Who was Ada Lovelace?

She was a mathematician who developed the first algorithm for the analytical engine. This was the world's first computer program.

What is open source software?

Software that anyone can modify and share.

What are transistors used for?

Storing electric voltages. They replaced vacuum tubes.

What is abstraction?

Taking a complex system and simplifying it for ease of use. We hide that complexity by providing a common interface.

Is 0011 a valid byte?

Technically but it's the same thing as 11. And technically not because it doesn't have 8 values!

Why was Microsoft so successful?

The OS could run on any compatible hardware.

What is cryptography?

The art of writing and solving codes. It was used to process messages in WWII.

What is the Xerox Alto?

The first computer with a GUI, that began to look like our modern computers. Now, families could have computers.

What is the digital divide?

The gap in IT skills due to socioeconomic factors, such as poverty, living in a rural town with limited internet access, and so forth.

What's an example of something a byte could represent?

The letter "c". Etc.

Why does an arrangement of 8 bits give us 2^8 possible values?

The number of possible groupings increases whenever another digit is added. As in, with 1 digit we have 2 values, with 2 digits we have 4 possible values, 3 digits we have 8 values, etc.

What is ASCII?

The oldest character encoding standard. We can represent characters, digits, and punctuation.

What is the hardware layer of computer architecture?

The physical components of the computer, such as keyboards.

What is IT?

The usage of digital technology to store and process data into useful information.

What are logic gates?

They are abstract devices, implemented electronically, that allow our transistors to decide WHERE to send electrical signals based on logical conditions.

What is the purpose of a compiler?

To translate human readable code into machine code.

How to convert decimal to binary?

Use the powers of 2 table: 128, 64, 32, 16, 8, 4, 2, 1. If there's a 1, add that number to the total, so 00001010 goes to 8+2=10.

How do computers represent color?

Using different color models, such as RGB. Mixing red, green, and blue can get you all the colors in existence. We use 3 characters, each of which represents a shade, the combination of which creates the pixel's color.

How does ASCII work?

We have a table where each letter/symbol matches to a byte in binary (a unique combination of eight 1s and 0s)

What happened next, in the history of computing, after the compiler was invented?

We saw the first HDD and microprocessors. After that, programming languages. And computers began to get smaller.

After the analytical engine, what was the next big leap in computing?

World War II. Computers were always very expensive. But with WWII, there was a strong motivation to provide funding for them.