I can understand limits thanks to different hardware standards (a phone that uses up to 32 GB SDHC cards not being able to use a 64 GB SDXC card) and different software standards (supporting FAT32 but not exFAT) but my current phone is rated to use up to 400 GB SDXC cards–I don’t understand why it couldn’t therefore also use 512 GB or 1 TB cards, which have the same hardware standard and (probably) same file system as the 400 GB card. Probably 400 GB cards were available but 512 GB weren’t at the time the phone was developed, but shouldn’t it support up to the limit of the standard, the theoretical 2 TB card?
SDXC is up to 2 (“binary”) terabytes, any larger and you need SDUC. But what happens when you slot an SD card larger than the “rated” capacity; does it complain?
One area where cards do vary is the bus and data rate; maybe it cares about them?
Possibly voltage used and how it is delivered. How much voltage thus magnetism is created in the cards. Some slots may not be designed to deliver the same.
Reading the OP carefully, it’s not whether you’re saying that SDXC cards larger than 400 GB actually don’t work, or just that the manufacturer’s literature says that only cards up to 400 GB will work. The latter case is easy to explain if as you say “400 GB cards were available but 512 GB weren’t at the time the phone was developed”. No responsible manufacturer is going to claim that something that they have never tested will work.
The manufacturer is only going to officially support cards that they can test at the time of product release. In all likelihood, your phone would work with a 2 TB SDXC card, but as you say, they don’t exist yet, and the manufacturer isn’t going to take the risk of saying it will work without verification. There could be some subtlety to how very high capacity cards would be implemented and the flash controller they use, for instance, that isn’t accounted for in the SD interface and driver on the phone.
A common issue that crops up is that the interface simply doesn’t have enough bits to address more than a certain amount of memory. This bit limitation can occur in lots of places. The protocol talking to the actual card, internal to the card controller in the host device, even in the operating system code. But actual hardware limitations crop up in all sorts of odd places. The controller will be a basic block, designed years ago and dropped onto the SOC design. Internally it could have all manner of optimisms to slim it down. The bit width chosen for some of the control registers may have been wild overkill years ago, but still enough to intrinsically limit the size of supported devices in the future.
Nonsense.
FWIW, this is the phone. I’m not looking to buy a 1 TB card, but if I’d like to buy a 512 GB one if I thought that it would work.
As an old timer with computers it is still amazing the sizes being mentioned here.
I saw an ad the other day for a 256 gig micro SD card for under $30. And yet it’s the size of a fingernail! And next year that will be seen as overpriced.
My first PC had a 20 meg HD. Before that I had used Xerox Altos with 2.5 meg removable platters the size of a thick pizza.
The speed of size growth coupled with price drops just messes with manufacturer’s ability to keep pace. What’s available during development is different from what’s available at release which is different from what’s available a couple years later.
And yet the internal storage of phones is annoyingly small and even the “more storage” versions cost way too much.
When consumer digital cameras first arrived on scene I remember buying 128K Compact Flash cards for over $100 and thinking it was a bargain. And of course Compact Flash cards were not at all compact, at least by today’s standards.
Sure, yet I want to believe that if a device says it supports a particular standard, then it actually supports that standard, in this case up to and including a 2 TB SDXC card, even if none were available at the time of testing. I don’t suppose he could try before he buys? Though a 512 GB card with a decent speed rating might be useful in any case.
Are you sure you don’t mean 128 megabytes? 128K is barely large enough for a few tiny, low-resolution images, and I don’t think memory chips that size have cost $100 since the 1980s.
Yeah, that’s probably it.
I don’t recall any consumer cameras with such a small card. My first digital camera was the Fuji DS-7, which came out in 1996. It had a resolution of 640x480 (0.3 megapixels, though the term “megapixel” didn’t really exist). It still came with a 2 megabyte SmartMedia card. Later Sony released a camera that used 1.44 megabyte 3.5-inch floppy disks for storage (very useful for workplaces because PCs didn’t have memory card readers but they all had floppy drives), and that’s the smallest digital camera storage I’ve ever come across.
I’m not prepared to say it’s impossible to make a 128 KB CF card, but the Wikipedia link lists 2 MB as the smallest size, which sounds about right for 1994-5. Max capacity for the current revision is theoretically 128 PB.
For what it’s worth, my Samsung tablet (Galaxy Tab S4) officially only supports 400GB, but I’ve been using a 512GB card in it. It’s been working fine so far. (Though I haven’t actually tried to put more than 400GB of data on it yet.)
If we’re going to stroll down memory lane… My first computer was a Commodore Pet with 8K of RAm. (yes, K) A friend who was a Ham Radio buff tried to solder in 32K chips, but the traces started lifting off the board. Then he reheated the solder joints and it worked, he’d just had a few cold-solder joints. My first digital camera in 200 was a Fuji 4900Z and took 32K cards - I think I finally got a 64K for it. It could take about 77 pictures on the card, and that’s also about how long the battery would last.
Typically, the different cards, chips, etc. use standard addressing schemes which require a certain number of address lines. When manufacturers realize they are going to hit the ceiling, they come out with a new standard that allows for more - and typically, plan far ahead beyond current manufacture capacity. However, it’s unusual but not unheard of for the operating system to not allow for addressing that high a capacity - IIRC my Fuji would address cards up to 64K although the standard allowed for 128K maximum. What seems odd to me is the number 400 - typically card capacities are powers of 2, so 256G or 512G seem more logical.
You are making the same error as GaryM–you keep saying 32 and 64 kilobyte cards when you mean 32 and 64 megabyte cards.
(I think that this was my first digital camera.)
The 400 GB cards came out before the 512 GB cards, just like the 200 GB cardscame out before the 256 GB ones. (Read those reviews–they are hilarious in retrospect.)
SD cards and such have more bits on them than the stated capacity. Wear leveling is used to try and distribute use of the blocks to lessen the likelihood that a block will go bad. When a block does go bad, an unused block is used in it’s stead.
Bad blocks are more common on the latest, greatest and therefore highest capacity cards. So the pool on those might be extra large. (After all, someone might be spending $400 on that new max capacity card and would not be pleased to see it’s total capacity going down early on.) Each block in the spare pool means one less block in the regular group.
In any case, there’s not really a power of 2 bytes on any of them.
No, not nonsense.
If there is a card reader designed for handling up to a certain capacity, it will have differences in how much voltage and current is able to be delivered from a new one that can write larger amounts. It is stored in these chips in solid state/ flash memory. If this is about magnetism, my apologies, it’s easier to describe that than saying “tiny cores holding an electric charges or voltage”
I know I quipped in the pit about how I hate citations, but here is a reliable and quick one; https://www.reference.com/technology/sd-cards-work-befa4e0fdedcc835