HDDs: The vinyl of data storage

Have you ever seen a Gramophone? Or touched a floppy disk? Chances are the answer to both these questions is a confused shrug- specially if you are from the Gen Alpha flock. You are more likely to see these wonders in a museum than in anyone’s drawing room or computer desk – or so you assume. And yet, these things were once the blue-eyed boys of their era.

So if you ever get to see either of these two relics, you would be able to wrap your head around HDDs – more easily. When the needle touches the groove of a gramophone, you can see it changing those grooves into soft swimming waves of sound through a horn (also- making old admirers immediately dig themselves into a deep chair, close their eyes and start swaying their necks) .

Coat a disk with some magnetic material, pin a read-write head for reading/writing data from/on this disk’s surface and you have your answer for storing data instead of songs! An HDD! Yes, almost like a gramophone that reads songs from a spinning record and plays it out.

The read/write head can move across the surface for exploring all the data spread across the disk. The disk spins at high speed and data is read/written in the form of changes in magnetic charges. Data gets stored in the shape of an electrical charge that emerges from an actuator arm - read/write head. These heads move on the platters guided by the software in the CPU and system board. There are bits of the sector on the disk and their corresponding charges get translated into binary forms- 1s or 0s.Connect this to the computer with an I/O interface and the HDD is ready to play the data you want.

HDD or Hard Disk Drive – have worked as a common storage device for the data we have on our devices – from laptops to PCs etc. They are very apt when the need is about large storage (we are talking GBs and TBs here); and when speed and durability do not matter so much. Unlike their next sibling, a SDD or a Solid State Drive, these HDDs are more mechanical in nature – with parts like actuator, arm, spindle, and platter. Of course, SDDs are faster, with a less fragile nature than that of HDDs and power-efficient but on a cost comparison they fade in front of HDDs. Also, HDDs are non-volatile – meaning that they are capable to retain the stored data even when no power is supplied to the device.

HDDs have been in play for use-cases where large storage capacities are involved and where cost per GB matters a lot. They also form a big fixture of many legacy environments. So don’t be surprised if you still find many using these disks instead of flash memory. The gramophone is still the centrepiece of many homes and the ‘apple’ of some eyes that live there. They may, someday, belong to the tribe of vinyl and floppies but- there’s time. Till you ask someone – have you ever seen a HDD?

Bonus point: Ever heard your IT Mr. Fix-it say the word defrag? That relates to HDDs. It stands for disk defragmentation. CPU writes data onto the HDD using a portion of a sector or sectors, but when any change happens to this data, the CPU looks for the next available sector. Now this hop from one sector to the next slows things down and is referred to as disk fragmentation. Which is where programs come in to defragment the disk- where the data is reshuffled so that all the relevant data can be slotted in one place instead of dancing all around. Aka Defrag.