A hard drive is a computer component that provides storage solutions (such as the SD card) for all digital data:
- operating system,
- photos and videos,
- any program and any application.
The storage of all these data is done on the basis of their sizes. The heaviest data necessarily takes up more space than the light data.
The size of the digital data is determined in megabytes, gigabytes, and terabytes.
An external hard drive is just a portable storage solution (similar to a USB drive) that can be used in both of the following cases:
- when you run out of space on your computer's internal hard drive,
- when you want to transport your data away from your computer.
The internal disk is a conventional hard disk connected to the computer through the motherboard by a connector (USB).
Difference between internal and external
The internal hard drive is an integral part of a computer and is connected directly to its motherboard while the external drive is a plus, usually plugged into a USB port directly attached to the motherboard.
High Tech product can have any capacity but maximum capacity standards are between 2 and 4TB. You still need to know that there is at least one new hard drive on the market that has a large capacity of up to 25TB.
Form factor and interface
Two form factors exist for disks:
-2.5" for the portables,
This kind has a compact size,
It is lightweight in weight, it is called pocket hard drive.
-3.5" for desktops,
This type is designed for fixed use,
Its storage capacities are very large.
For the interface, the new models use USB3 instead of USB2.
The different transfer speeds possible in revolutions/min are:
- For the 2''1 / 2 (portable)
5400 rpm basic format
7200 rpm format plus
- For 3''1 / 2 (desktop computer)
7200 rpm basic format
10000 rpm on SATA and SCSI drives
15000 rpm only on SCSI disks.
The external hard drive HDD
The HDD employs a mechanical system consisting of several trays, usually aluminum for its lightness, mounted on a shaft rotating with an engine.
These trays are covered with electromagnetic layers that retain the data when the disk is not in use.
Each of the existing trays is provided with a read/write head that a second motor controls. This second motor moves all the heads at the same time.
The main role of these heads is to collect the digital data which will subsequently be transferred to a pilot controller of the engines.
The collected data are formatted and transmitted to the computer via its motherboard.
Flow or data transfer rate
Access time is the time taken for each head to come to the right place for reading or writing.
The longer this head takes to be in the right place on the board, the longer the read/write operation takes.
The SSD portable hard drive
The external SSD external hard drive is the type of hard drive's recent hard drive that does not rely on the same system as the HDD. Indeed, it uses a different technology since we go from mechanics to electronics (flash memory).
SSD uses electronic components for data storage like computer RAMs with the difference that stored data is not lost when the disk is not in use.
Trays, rotating shafts and HDD motors are replaced by electronic components.
The SSD is equipped with cells that write data and provide this data for reading. But these cells have a limited lifetime in writing. This has the effect that after a certain time, the first cell used becomes unusable in writing. The system automatically opts for the next cell. The data is not lost but the storage capacity deteriorates.
Comparison between HDD and SSD
Advantages of HDD disks
- Lifespan: It is almost unlimited except in case of mechanical failure which can occur at a minimal frequency,
- Transfer: Backups are quickly made since the transfer speed is great,
- Cost: With equal capacity, HDD external drives are much cheaper.
Advantages of SSDs
- Silent: Since there are only electronic components, it is quiet in operation,
- Shockproof: Shocks have a big impact on mechanical parts and little on electronic components,
- Heating: Electronic parts heat much less than mechanical parts subject to friction.
- Speed: The latency is very low, this type of disc is very fast.
Major disadvantages of SSD
So far, three major drawbacks have slowed the spread of SSD: price, storage capacity and service life.
But progress has been made and these three disadvantages are slowly disappearing.
Indeed, the price gap is shrinking, storage capacity is changing and the service life is improving.
Most computers use the system backup used from the computer to an external storage device, the opposite is not true.
There is however a backup software called AOMEI Backupper which is free. It allows the recovery of data from one storage space to another. The big fihiers do not worry it. Just plug in its USB external drive.
You should also know that there is an option that allows automatic backup of files. Software of this type is compatible with all disks.
The disk is usually sold pre-formatted in fat32 or ntfs but it is still possible to format and reformat it at any time.
- Cost: With equal capacity, it is much cheaper.
The portable external drive of commerce
To be equipped with a hard disk, you have to buy it, which is not easy. You just have to know that the best hard drives belong to the most requested brands are the Toshiba, the Maxtor, the Western Digital Elements, the Seagate. But many other brands are also popular and some models have a sleek design especially the ultra slim.
Storage capacity is usually 500GB, 1TB, 2TB and 3TB. It can go up to 4TB and even more.
The portable external hard drive is housed in a shockproof case, formatted from the factory, equipped with its USB cable.
You have to know how to choose and buy your equipment at lower price (since it exists) and cheap in some models of the market with a good price/quality ratio.