List of Hitachi/HGST model number codes
This is a list of the trailing letter codes in Hitachi and HGST model number codes (for example, and their meanings. This model number format is used on all post-IBM takeover Hitachi drives, all HGST drives, and Western Digital Ultrastar drives.
Prefix: Manufacturer
The first letter indicates the manufacturer. Models released prior to 2018 have a H (for Hitachi or HGST), whereas models since 2018 have W instead, after Western Digital.
| Code | Manufacturer |
|---|---|
| H | Hitachi/HGST |
| W | Western Digital |
Second letter: Business unit
The first letter defines the business unit the drive was released under.
| Code | Business unit | Notes |
|---|---|---|
| C | CinemaStar | |
| D | Deskstar | |
| E | Endurastar | |
| M | MegaScale | |
| T | Travelstar | |
| U | Ultrastar |
Third letter: Option
The third letter defines additional information about the drive relative to the business unit.
| Code | Meaning | Used with | Notes |
|---|---|---|---|
| C | Microdrive | C | Denotes a 2.5" CinemaStar. |
| T | Denotes a 1.8" Travelstar. | ||
| J | Higher endurance | E | |
| H | Helium | U | |
| T | Higher density | D | Models with this unit have higher density than those with an S. Beginning with the Hitachi Deskstar 7K1000.C this was discontinued. |
Fifth and sixth digits: Spindle speed
The fifth and sixth digits indicate the spindle speed of the drive.
Seventh and eighth digits: Maximum capacity for this drive's family
The seventh and eighth digits indicate the maximum capacity for the model's family, rounded to two significant digits. For example, the Hitachi HDS721050CLA662 was released under the Hitachi Deskstar 7K1000.C family, whose highest capacity model is 1 TB.
Ninth and tenth digits: Model's capacity
The seventh and eighth digits indicate the capacity for the model itself, rounded to two significant digits. For example, for the same HDS721050CLA662, the capacity is 500 GB, so it gets a "50".
Eleventh digit: Generation code
The eleventh digit is a generation code. Prior to the Deskstar 7K1000.C or Hitachi Travelstar 5K500.B, this code was connected to the codename, with some exceptions. For example, many Vancouver-III models got a "V" for this code. Starting from the aforementioned families, the letter instead increased sequentially from A depending on how many families were released for that maximum capacity and form factor in the past. For example, for the same HDS721050CLA662, the generation code is "C", due to the fact it is the third family toppping out at 1 TB released, with the prior families being Hitachi Deskstar 7K1000 and Hitachi Deskstar 7K1000.B.
Twelth digit: Form factor code
The twelth digit indicates the form factor of the drive.
| Code | Form factor/z-height |
|---|---|
| 7 | 2.5" 7 mm |
| 9 | 2.5" 9.5 mm |
| T | 2.5" 12.5 mm |
| L | 3.5" 26.1 mm |
Thirteenth and fourteenth digits: Interface and sector size
The twelth digit indicates both the interface and sector size of the drive.
| Code | Interface | Advanced Format? |
|---|---|---|
| AT | PATA | No |
| SA | SATA 1.0 | No |
| A3 | SATA 2 | No |
| E3 | SATA 2 | 512e |
| A6 | SATA 3 | No |
| E6 | SATA 3 | 512e |
| N6 | SATA 3 | 4Kn |
Fifteenth digit: Cache or PWDIS support
Prior to the HGST Ultrastar 7K6000, the fifteenth digit indicates the amount of cache. Note that this digit is mostly unused and set to 0 on 2.5" drives prior to the Hitachi Travelstar Z5K320. Since the HGST Ultrastar HC310, this digit instead indicates whether Power Disable is supported.
| Code | Meaning |
|---|---|
| 2 | 2 MB cache |
| 8 | 8 MB cache |
| 6 | 16 MB cache |
| 3 | 32 MB cache |
| 4 | 64 MB cache |
| 1 | 128 MB cache |
| 0 | Either has no meaning on 2.5"s, or indicates PWDIS supported |
| L | No PWDIS support ("Legacy Pin 3 config") |
Sixteenth digit: Extra information
The sixteenth digit indicates additional, family-dependent information. For example, it could indicate the presence of a free-fall sensor or self-encryption.