HGST HUS724020ALE640 2TB SATA Ultrastar HDD: Part Number Decoded
Ultrastar part numbers look like registration plates. HUS724020ALE640 tells you nothing at a glance, and that is a problem when you are trying to work out whether the drive in a search result is the drive your array needs.
The HGST HUS724020ALE640 is a 2TB SATA 6Gb/s 7200RPM 3.5-inch Ultrastar nearline drive, and this is a good part number to learn to read because the pattern applies across the family.
Reading an Ultrastar part number
Break it into pieces and it stops being random.
HUS identifies the Ultrastar enterprise line in the 3.5-inch form factor. Its counterpart HUC denotes the 2.5-inch line — useful shorthand when scanning a list of results.
7 indicates the 7200 RPM class. Ultrastar 15K drives use different family coding entirely.
24 is the family generation.
020 is the capacity in this case 2TB. On a 4TB drive from the same family you would see 040.
ALE encodes the interface and sector configuration — the ALE grouping indicates SATA on these drives, where SAS variants carry different lettering.
640 covers the cache and firmware revision.
You do not need to memorise this. What matters is knowing that the string is systematic rather than arbitrary, so a drive described only as "2TB Ultrastar SATA" is not precisely identified — several parts fit that description across generations, with different firmware. Order against the full string.
HUS724020ALE640 specifications
| Part Number | HUS724020ALE640 |
| Manufacturer | HGST / Western Digital |
| Product Family | Ultrastar 7K4000 class |
| Capacity | 2TB |
| Interface | SATA 6Gb/s |
| Rotational Speed | 7200 RPM |
| Form Factor | 3.5 inch LFF |
| Drive Class | Enterprise Nearline |
| Condition | Refurbished, function-tested |
| Warranty | 30-day TechSellerUSA warranty |
Why the exact revision matters in an array
For a standalone drive in a workstation, near enough is fine. In an array it is not, and the reason is consistency rather than quality.
RAID controllers work with drives as a set. Firmware revisions differ in how they handle error recovery timing, how they report health telemetry, and how they respond to controller commands during a rebuild. Mostly those differences are invisible. Occasionally they are not, and the symptom is an array behaving oddly in ways that are hard to attribute.
Matching the exact part number when replacing a member removes that variable entirely. It costs nothing extra and it eliminates a category of problem that is genuinely difficult to diagnose after the fact.
This is also why we list drives by full part number rather than by capacity and interface. "2TB SATA nearline" describes dozens of products.
SKU: HUS724020ALE640  | Refurbished & function-tested  | 30-day warranty
View Details & Request a Quote →Ultrastar, and the three-way brand history
You will see this drive described as HGST, Hitachi or Western Digital, and all three are defensible.
The lineage runs IBM to Hitachi to HGST to Western Digital, with each acquisition inheriting the product lines and the part numbering. Ultrastar came through that chain and remains Western Digital’s enterprise designation today, sitting alongside the Gold branding that replaced the older WD RE line.
Practically, brand on a listing is noise. The part number is the identifier. If your documentation says HUS724020ALE640, that string is what you order regardless of which of the three names appears above it.
Bare drive, generic chassis
This is the manufacturer part with no server carrier and no OEM firmware coding. It suits Supermicro builds, white-box storage servers, JBOD enclosures and NAS units with generic trays, and costs less than an OEM-branded drive on the same mechanism.
It is the wrong choice where an HPE Smart Array, Dell PERC or IBM ServeRAID controller expects vendor firmware, or where you need the tray supplied. Our compatibility guide lists the OEM part numbers for each platform.
Ordering
We supply the HUS724020ALE640 refurbished and function-tested with a 30-day warranty, single spares or in volume. Browse the full Western Digital and HGST range or our complete enterprise hard drives catalogue.
Common questions
How do I read an Ultrastar part number?
It is systematic rather than arbitrary. HUS denotes the 3.5-inch enterprise line and HUC the 2.5-inch one, followed by RPM class, family generation, capacity, interface and sector coding, then cache and firmware revision. The full string identifies the drive precisely where a capacity-and-interface description does not.
Does the exact firmware revision matter?
In an array, yes. Revisions differ in error recovery timing, health telemetry and rebuild behaviour. Mostly those differences are invisible; occasionally they produce odd array behaviour that is hard to attribute afterwards. Matching the exact part number removes the variable at no extra cost.
Is this an HGST, Hitachi or Western Digital drive?
All three are defensible. The lineage runs IBM to Hitachi to HGST to Western Digital, with each acquisition inheriting the product lines and part numbering. The part number is the identifier; the brand on a listing is noise.
What is the difference between HUS and HUC part numbers?
HUS denotes the 3.5-inch Ultrastar enterprise line and HUC the 2.5-inch one. It is useful shorthand when scanning search results, since form factor is usually the first thing that rules a drive in or out.
Tell us the exact part number from your array and we will match it rather than substituting an equivalent.
