Definition of firmware:
Since modern hard disks have internal microprocessors, they also have internal “software” that runs them. These routines are what run the control logic and make the drive work. Of course this isn’t really software in the conventional sense, because these instructions are embedded into read-only memory. This code is analogous to the system BIOS: low-level, hardware-based control routines, embedded in ROM. It is usually called firmware, with the word “firm” intending to connote something in between “hard” and “soft”. The functions that run the logic board’s circuitry could be implemented strictly with hardware devices, as was done with early drives. However, this would be expensive and inflexible for today’s sophisticated controllers, since it would make it difficult to update or adapt the logic to match changes in hard disks or the devices they interface with.
Much the way the system BIOS benefits from being in a changeable ROM chip that can be modified relatively easily, the hard disk’s firmware does as well. In fact, in many drives the firmware can be updated under software control, very much the same way that a flash BIOS works. Unlike the system BIOS, this is only very rarely done, when a particular sort of problem exists with the firmware logic that can be fixed without requiring a physical hardware change. You can check the drive manufacturer’s web site for more details.
In short, without the firmware code, no communication will be possible between the PC system and the hard disk.
Where the firmware stores?
Modern disks normally have their firmware codes located on data platters and also the PCB board. If the firmware area is corrupted, the drive will appear to have failed even all the electrical and mechanical components are still fully functional.
You may know the importance of firmware on the HDD function. And know the firmware is like the micro codes between the elements of HDD. And what will it happen if there are some firmware corruptions?
Let’s see the symptoms of firmware corruption before the solutions given:
1. Drive powers up, but is not recognized /defected by the computer
2. Drive powers up, but is recognized wrongly, sometimes with nonsensical characters, manufacture alias (Such as N40p for Maxtor 6Y and etc ;);
3. Drive freezes during booting up;
4. Drive detect in wrong Capacity, such as 80 GB detected as 1Mb;
5. S.M.A.R.T error;
6. Drive is locked by human error; such as Hitachi hard drive by a drop; it is a self protection method of HDD design;
7. Drive clicking ;( it can be caused by firmware too, the heads try to read the SA on platters and can not positing 😉
The firmware is very confidential to common users and the HDD manufacturers will never publish to the public.