This article provides an in-depth explanation of how hard disk drives (HDDs) work. The author begins by explaining the compactness of data storage in HDDs, comparing it to the amount of pictures that can be stored within a single dot of ink from a ballpoint pen.
The author then opens up a hard drive and explains the various components, including the disk or platter that stores data, the spindle that spins the disk, the head stack assembly with a read/write head, and the voice coil motor that moves the arm assembly.
The article delves into the details of how data is stored on the disk, including the use of magnetic domains, tracks, and sectors. It also explains how the read/write head works, using a giant magneto resistance (GMR) material to detect changes in magnetic fields.
The author also discusses advancements in hard drive technology, including the switch from horizontal to vertical magnetic domains, shingled magnetic recording (SMR), and heat-assisted magnetic recording (HAMR).
The article concludes by thanking the sponsors and encouraging viewers to watch other videos by Branch Education, which creates 3D animations to explain complex technologies.
Key takeaways:
* HDDs store data in a highly compact form, with a single dot of ink from a ballpoint pen being equivalent to the storage capacity of a year's worth of pictures.
* The components of a hard drive include the disk or platter, spindle, head stack assembly, and voice coil motor.
* Data is stored on the disk using magnetic domains, tracks, and sectors.
* The read/write head uses GMR material to detect changes in magnetic fields.
* Advancements in hard drive technology include the switch from horizontal to vertical magnetic domains, SMR, and HAMR.
* HDDs have become increasingly compact and affordable over the years, with a significant reduction in cost per bit.
Here are the key facts extracted from the text:
1. A hard disk drive (HDD) stores data in a compact form, similar to how many pictures can fit in a single dot of ink from a ballpoint pen.
2. A HDD uses a magnetic disk, or platter, to store data.
3. The disk is composed of an aluminum-magnesium alloy with multiple coatings of other alloys.
4. The magnetic functional layer of the disk is a 120-nanometer-thin layer of a cobalt-chromium-tantalum alloy.
5. The disk is mounted on a spindle that spins at a speed of 7200 RPM using a brushless DC motor.
6. A head stack assembly is used to read and write data to the disk.
7. The head stack assembly has one arm above and one arm below each disk, with a slider and a read-write head at the end of each arm.
8. The slider is designed to catch the airflow generated by the spinning disk and use it to float or fly the read-write head.
9. The read-write head is only 15 nanometers away from the surface of the disk.
10. A voice coil motor is used to move the arm stack assembly.
11. The voice coil motor is composed of a coil of wire and two strong neodymium magnets.
12. The arm stack assembly is parked to the side on a small piece of plastic when the disk is not spinning.
13. A SATA connector is used to connect the HDD to a motherboard.
14. A separate connector is used to connect the HDD to a power supply.
15. The HDD has a gasket that seals the disk from the exterior environment.
16. Two filters are used to catch any stray dust particles.
17. The disk is divided into concentric circles of tracks.
18. The latest HDDs can have more than 500,000 tracks on one side.
19. Each track is divided into sectors.
20. Each sector has a preamble or synchronization zone.
21. Each sector has an address that helps the read-write head know which track and sector it's currently positioned over.
22. Each sector has actual data stored in it, typically 4 kilobytes of data per sector.
23. Each sector has an area for an error-correcting code (ECC).
24. The ECC is used to verify that the data stored in the block is accurately written and properly read.
25. The read-write head uses a multi-layer conductive material to detect magnetic fields.
26. The material has a property called giant magneto-resistance (GMR).
27. The GMR material changes its resistivity depending on the strength of magnetic fields that pass through it.
28. The read-write head measures the resistivity to detect changes in magnetic domain orientation.
29. The HDD has a preamble that is used to set the size of each domain.
30. The ECC is used to ensure that no data is lost.
31. Advances in HDD technology have increased aerial density by over 50 million times in the past 60 years.
32. The cost to store trillions of bits of data has dropped by over 100 million times since the 1960s.
33. Around 2010, the orientation of the magnetic domain was switched from horizontal to vertical.
34. Shingled magnetic recording (SMR) is a technology that allows tracks to be written to partially overlap with previously written tracks.
35. Heat-assisted magnetic recording (HAMR) is a technology that uses a focused laser to heat the region that is actively being written to by the read-write head.
36. HAMR is not yet commercially available.
Note that these facts are based on the provided text and may not be comprehensive or up-to-date.