Noob to Hacker

Today was a very long day and I didn’t have time to study, still managed to pull through and learned some interesting things.

1. Programs are also “data” stored on RAM addresses like anything else. They are a series of instructions, numbers, addresses… RAM btw, is just a series of slots where 1 and 0 are stored :), and a link to the CPU.
2. Now there is a game happening between CPU and RAM, and info is exchanged constantly between these twp. CPU accesses RAM constantly and executes intructions etc.
3. Inside the CPU itslef, the game happens between the Control Unit and the ALU.
4. The CPU at the end of the day are wires carrying info, on/off, high/low voltage, which represent the 0’s and 1’s.
5. There is always one wire that turns on and off at a given rate, the clock, and how many times per second this happens (HZ) is basically what we hear of 2Ghz processor… this means the clock switches on and off 2 Billion times per second! That is one of the things that allows so many computations to happen so quickly.
6. How does a CPU work? Well, it seems pretty damn hard to fully understand, but this video is really awesome in breaking it down. Although I don’t fully get it (Will re-watch another day again slowly), at the end of the day there seems to be a game between the Control Unit and the ALU, helped by “flags” (don’t understand yet) and “registers” basically a component used to “store” a value for some time. These are like a little RAM inside the CPU itslef.
7. In terms of possible CPU instructions in RAM, there seem to be different depend on CPU. But in the video it explains the following: LOAD (Fetches value from RAM), ADD (Adds two values together), STORE (Saves result in RAM), COMPARE (Compares 2 numbers together to see which one is larger, or if they are the same), JUMPIF (If certain condition is met, go fetch a specific variable from an out of order RAM address), JUMP (Jumps without condition), OUT (Output data to external device like a monitor), or IN (Fetches data from external device like keyboard).

As a pending task I need to re-watch the video again and try my best to fully understand the example little program it puts. I feel it is super important to understand this well to get the essence of every computation later on.

I need to also clarify what is the essential differences between the ALU and the Control Unit.

If ever want to go deep into this they reccomend a book in the video “But How do It Know“? I might read it in the future, or might not. Not sure.

I am still following both courses I talked about on previous post.

Today I learned:

• Binary numbers and how to switch from decimal to binary and reverse (This I already had some previous knowledge). I also learned they are represented always with 4 digits, so if you wanna write 3 in binnary, instead of writing “11”, you write “0011”. Two groups of these form a “byte”. And this means that if you have 1MB storage (1.000.000 bytes), this means you can store 8.000.000 “0”‘s and “1”s in that file!
• Hexadecimal numbers – This I didn’t know about. It is a very interesting concept in which each set of 4 digit binary numbers can be respresented with just 1 character. (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F). This is super interesting and makes sense. At the end of the day is like “Compressing” the binary system even more, so every number placer is now a power of 16, instead of a power of 2. This allows to reproduce big binary numbers in much shorter notation, and to switch from one notation to another with ease. – Have you seen “The Martian”? Hahah – Now I understand the code they use to communicate. Basically the signs around the bot are the 16 hexadecimal possibilities, and then he uses a table where each hexadecimal number is translated into a “Character” of our alphabet, allowing earth to communicate with Matt Damon – You see, one day of work and already feeling smarter. 😀
• In computers everything is 0/1. I learned that there are 8 bits in 1 byte, and now things start to make sense.
• “In any program there must be a specification of what kind of data you are working with… is it numbers, are they strings?”
• RAM is memory that only exists when computer is on – Programs use it! – Interesting… and also programming languages help us keep track of where are things in RAM whenever something needs to be recalled so that we don’t have to memorize that.
• On MIT course very interesting… Code is like a RECIPE. You need some tool in which you can input a RECIPE and then it does what the recipe says. This is an Interpreter. Also, the recipe needs to be writen in a particular language, which is the programing languages! – Explained difference syntax – semantics.
• On MIT course it also stressed out importance of developing a coding style.

Those are just my anotations. And for the moment I will proceed just annotating things I find helpful! 

*Image above shows how quickly people give up. So don’t expect me to be different… I might keep going or I might drop soon… noone knows. 

What are your goals now?

I don’t have clear goals right now, but I am not worried. I want to start taking generic courses first to warm up and learn the basic concepts, and then I will switch into trying to apply what I learn through more practical courses.

I am gonna try follow these two courses for the moment:

MIT – Introduction to Computer Science and Programming

Alison – Introduction to C Programming

I will then little by little start re-aligning my learning towards more and more purposeful targets.

Generic goals:

• Being able to better understand programming language basics in general
• Understand what “Objective Oriented Programming” actually means, and why there is so many myths about it
• Try to learn through Python and C at the beginning, but being ready to change to other languages if necessary

Let’s start!