HDD and SSD , What to choose?

HDD and SSD are both storage drivers, which stores data files or accessing little data transactions.
HDD or also called hard disk drive, has a moving disk which moves like a CD. It stores a lot of data compared to SSD, but usually wears off/breaks when using a long period of time.
SSD also called solid state drive, is a chip that can run software faster than HDDs. It is faster and does not have a disk like HDD, however it is expensive as 500gb of storage is around 150 dollars in present day and also writing on them heavily can also wear the drive.
Both of the drives are reliable and HDDs are being recommended if you store a lot of files while SSDs are used to access software much more faster i.e adobe photoshop.
https://youtu.be/YQEjGKYXjw8

A small explanation about SDRAM and DRAM 

RAM , also called random access memory, which is a type of a computer memory that can be accessed randomly. RAM can access to data much more faster than the hard drive which could directly access the data stored inside, which allows the computer to run much more faster.

There are two types of RAM; DRAMs and SDRAMs .

DRAM also called dynamic ram is the ram we use mostly in our personal computer.It constantly needs to be refreshed(re energized) to prevent loss of contents.

SDRAM also called static dynamic ram, is the ram which is mostly inside of a CPU. It is called static for because of  it does not need to be constantly to refresh/re energize. 

SDRAM is expensive and also faster than DRAM. For example a 512 megabyte of SDRAM can access data faster than a 8 gigabyte of DRAM.

Referneces; https://www.reference.com/technology/ram-used-edda71d108b2303

                    http://www.webopedia.com/TERM/R/RAM.html

Electronic data and instructions

System unit is an electronic circuitry which contains different type of components called microprocessor. 

System unit cannot make a directly process such as requests.(computer only recognizes electronic signals.)

Electronic data is the a digital, magnetic stored data which store all kind of stuff such as documents, software and others.Electronic data can be a hard disk , CD ROM, floppy disks ,etc.

data is being represented as two state system or Binary System [0's(off) and 1's(on)]

They are called character encoding

The Binary character encoding consists of;

ASCII also called American standards code for information interchange and is used in microcomputers to represent characters.

EBCDIC also called Extended binary coded decimal Interchange code and used in mainframe computers. These schemes were quite effective but limited.

UNICODE. A popular and most widely used in present day. When internet exploded, it has been founded and is now widely used because of its 16 bits (many number of bits which also allows non English character or special characters to be represented ).

credits: https://prezi.com/i7un_u8key5u/electronic-data-and-instruction/?webgl=0