Apologies for the slightly clickbaity title! I could not resist. While an Intel employee did tell me this, they are obviously wrong.
Still, I found out some interesting things that I was previously unaware of.
I was thinking of purchasing some “3.84TB” Intel D3-S4610 SSDs for work. I already have some “3.84TB” Samsung SM883s so it would be good if the actual byte capacity of the Intel SSDs were at least as much as the Samsung ones, so that they could be used to replace a failed Samsung SSD.
To those with little tech experience you would think that two things which are described as X TB in capacity would be:
- Actually X TB in size, where 1TB = 1,000 x 1,000 x 1,000 x 1,000 bytes, using powers of ten SI prefixes. Or;
- Actually X TiB in size, where 1TiB = 1,024 x 1,024 x 1,024 x 1,024 bytes, using binary prefixes.
…and there was a period of time where this was mostly correct, in that manufacturers would prefer something like the former case, as it results in larger headline numbers.
The thing is, years ago, manufacturers used to pick a capacity that was at least what was advertised (in powers of 10 figures) but it wasn’t standardised.
If you used those drives in a RAID array then it was possible that a replacement—even from the same manufacturer—could be very slightly smaller. That would give you a bad day as you generally need devices that are all the same size. Larger is okay (you’ll waste some), but smaller won’t work.
So for those of us who like me are old, this is something we’re accustomed to checking, and I still thought it was the case. I wanted to find out the exact byte capacity of this Intel SSD. So I tried to ask Intel, in a live support chat.
Edgar (22/02/2021, 13:50:59): Hello. My name is Edgar and I’ll be helping you today.
Me (22/02/2021, 13:51:36): Hi Edgar, I have a simple request. Please could you tell me the exact byte capacity of a SSD-SSDSC2KG038T801 that is a 3.84TB Intel D3-S4610 SSD
Me (22/02/2021, 13:51:47): I need this information for matching capacities in a RAID set
Edgar (22/02/2021, 13:52:07): Hello, thank you for contacting Intel Technical Support. It is going to be my pleasure to help you.
Edgar (22/02/2021, 13:53:05): Allow me a moment to create a ticket for you.
Edgar (22/02/2021, 13:57:26): We have a calculation to get the decimal drive sectors of an SSD because the information you are asking for most probably is going to need a Non-Disclousre Agreement (NDA)
Yeah, an Intel employee told me that I might need to sign an NDA to know the usable capacity of an SSD. This is obviously nonsense. I don’t know whether they misunderstood and thought I was asking about the raw capacity of the flash chips or what.
Me (22/02/2021, 13:58:15): That seems a bit strange. If I buy this drive I can just plug it in and see the capacity in bytes. But if it’s too small then that is a wasted purchase which would be RMA’d
Edgar (22/02/2021, 14:02:48): It is 7,500,000,000
Edgar (22/02/2021, 14:03:17): Because you take the size of the SSD that is 3.84 in TB, in Byte is 3840000000000
Edgar (22/02/2021, 14:03:47): So we divide 3840000000000 / 512 which is the sector size for a total of 7,500,000,000 Bytes
Me (22/02/2021, 14:05:50): you must mean 7,500,000,000 sectors of 512byte, right?
Edgar (22/02/2021, 14:07:45): That is the total sector size, 512 byte
Edgar (22/02/2021, 14:08:12): So the total sector size of the SSD is 7,500,000,000
Me (22/02/2021, 14:08:26): 7,500,000,000 sectors is only 3,750GB so this seems rather unlikely
The reason why this seemed unlikely to me is that I have never seen an Intel or Samsung SSD that was advertised as
X.Y TB capacity that did not have a usable capacity of at least
X,Y00,000,000,000 bytes. So I would expect a “3.84TB” device to have at least 3,840,000,000,000 bytes of usable capacity.
Edgar was unable to help me further so the support chat was ended. I decided to ask around online to see if anyone actually had one of these devices running and could tell me the capacity.
Peter Corlett responded to me with:
As per IDEMA LBA1-03, the capacity is 1,000,194,048 bytes per marketing gigabyte plus 10,838,016 bytes. A marketing terabyte is 1000 marketing gigabytes.
3840 * 1000194048 + 10838016 = 3840755982336. Presumably your Samsung disk has that capacity, as should that Intel one you’re eyeing up.
My Samsung ones do! And every other SSD I’ve checked obeys this formula, which explains why things have seemed a lot more standard recently. I think this might have been standardised some time around 2014 / 2015. I can’t tell right now because the IDEMA web site is down!
So the interesting and previously unknown to me thing is that storage device sizes are indeed standardised now, albeit not to any sane definition of the units that they use.
What a relief.
Also that Intel live support sadly can’t be relied upon to know basic facts about Intel products. 🙁