Product datasheet of HitachiGST hard disk models - HDS7230xxALA640 - explanation:
HDS723030ALA640 = 3TB, 64MB buffer
H = Hitachi
D = Deskstar
S = Series prefix
72 = 7200 RPM
30 = Full capacity — 3TB
30 = Capacity this model, 30 = 3TB
(20 = 2TB, 15 = 1.5TB)
A = Generation code
L = 26.1mm z-height
A6 = Interface, SATA 6Gb / s
4 = 64MB buffer
0 = Reserved (2 = Reserved)
What does it mean in the explanation that:
*** "30 = full capacity = 3TB"
*** "20 = capacity [this model] = 2TB"
It would not be easier to write simply: "capacity of this disk model = 2TB"?
Can it be related to the fact that the whole family of disks with max. capacity 3TB (as in the example above - the HDS7230xxALA640 model family) is divided into 3 parts:
a / model with full capacity 3TB - 3030. capacity limitation not installed.
b / model 3020 with capacity limited to 2TB. The same model without this limitation would have 3TB.
c / model 3015 with capacity limited to 1.5TB. The same model without this limitation would have 3TB.
Of course, according to serious specialists - "these are unauthorized rumors and sick speculations of sick people". Maybe yes?...
But the question of total, absolute, 100% non-specialist remains:
*** Does the 3030 model have a different number of plates than the 3020 in the HDS7230xxALA640 family? or 3015? Or maybe the same, only smaller?
*** Or maybe in these 2TB and 1.5TB models - some plates are not covered with magnetic media? Or something else is the reason for these capacity differences. What is this?
*** For what technical reason the 3020 (2TB) and 3015 (1.5TB) models have less capacity than 3030 (3TB)?