If there's a single company issuing them how are there companies using ones with invalid checksums?
What you do within that range is up to up, you don't actually have to ask the authority for every single number within the range. As a simplification: If you get the number from 100 to 200 to assign to your books but the last digit is a check digit, you didn't get 100 numbers to choose from. You got to choose from: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 and the third number is the check digit, which is computed from the other numbers. Just with ISBNs (and other numbering schemes) the numbers are larger of course.
Going back to the IP address analogy: if you are issued 126.96.36.199/8, you can use anything from 188.8.131.52 to 184.108.40.206 but you don't have to start with 220.127.116.11 and you don't have to treat it as one big /8 either. You can subdivide it into multiple /28s for example.
The only difference here is that with ISBNs (or anything else that has a check digit) is that the last digit is not freely usable. It's just a check digit. It's not really part of the range so to speak. It's like you subdividing your /8 into lots of /28s but ignoring the fact that the network address on the /28s is actually the network address and having one of the computers in your network use it as their actual IP address. That's obviously gonna wreak some havoc because some of your network thinks it's a network address for one of the /28s and some others think it's an individual computer.
Hence the article says:
> Shel very quickly removed all ‘checksum software checks’ (which would have made sure it was a legal ISBN)
I find it incredibly fascinating (and a little bit depressing) that publishers would twist the system in that way, but maybe it has to be expected if something is sold for a large amount of money.
In France ISBN are free; there is a central agency (Electre) that issues them but they don't charge for it (at least not to small publishers).
But EAN/UPC codes are issued by a different agency, GS1, that does charge a recurring fee, and it is expensive and "infinite" (you're supposed to keep paying for as long as you're using the codes). But even them don't charge for the range size; the fee is based on the turnover of the company buying the codes.
In general, are check digits common in schemes like these? Is it something you'd do if you expect lots of manual copying, or scanning or other potentially-error-producing conversions?
Upon a quick reading of the Wikipedia article on EAN-13 it appears that there is some parity to determine the direction of the scan (i.e. upside-down or upright) but the numbers are encoded as-is without any further error correction contrary to e.g. QR codes.
Alas, for a definitive answer on the reasoning one might have to buy the relevant ISO standard, if it is even described there.
Given that human adults are said to be able to keep 5-9 items in working memory, I would think it prudent to include a check digit for the ISBN when one might be required to manually enter them into search masks, forms, etc. and if only hearing it (e.g. over the phone) might not benefit from the grouping they visually gain from the interspersed dashes.
On the topic of correctly copying (manually):
whenever I have to be certain to correctly transcribe a long important number or string I would at the end cover up both the source and the transcription, then reveal one character from the end, then the second to last on e.g. the source, verify that the last and the second to last on the transcription matches (in that order!), then uncover the next 2 on the transcription, verify against the source, continue with the source and so on.
This helps immensely to discover transposed digits (especially since my mother tongue is German where we swap the tens and ones while speaking (or thinking with the inner voice) a 2-digit number) and not glance over well known digit groups such as zip code or special dates, etc.
And International Bank Account Numbers (IBANs) have two check digits, but at the front, not at the back. And having check digits is important, because it might not be easy to get your money back, if transferred to some unintended account.
The IBAN consists of up to 34 alphanumeric characters comprising a country code; two check digits; and a number that includes the domestic bank account number, branch identifier, and potential routing information. The check digits enable a check of the bank account number to confirm its integrity before submitting a transaction.
Lots of examples at https://en.wikipedia.org/wiki/Check_digit
But for books, the worst that can happen is that you get the wrong book. Maybe back in the days when people ordered books via phone it was good to have a checksum, but even then the seller would probably read back the name of the book. So I don't really see how it's necessary here.
I would love to hear from a botanist/banana-related person what a bunch of banana plants are called. Are there similar differing names as for groups of various animals?
Seriously so, Amazon's ASINs are among the best part number systems I encountered in my life so far. And it is incredibly scaleable as well!
Originally I thought the ASIN had to be valid, but eventually realized it didn't even matter, just had to match the pattern.
Normally, books sent via USB can't use Whispersync to sync reading position between different devices. OP is saying that if you embed ASIN into the book (can just be a random ASIN) and sideload the same books to multiple device, they will sync, too.
Honestly I expect they'll hit some big problems when they first allocate ASINs beyond Bxxxxxxxx as I'm sure a lot of software has begun to expect all ASINs to either be an ISBN or start with "B".
Correct. It is an FNSKU (Fulfillment Network SKU), which is both product- and seller-specific.
Amazon listing for item with ASIN B1234567:
* Seller 1 sells on the listing. His inventory of B1234567 is assigned FNSKU X8675409. When he sends inventory to Amazon, each unit must have a sticker with X8675409 covering the UPC code, or the seller can pay a fee for Amazon to affix the sticker.
* Seller 2 sells on the listing. His inventory of B1234567 is assigned FNSKU X4894608. When he sends inventory to Amazon, each unit must have a sticker with X4894608 covering the UPC code, or the seller can pay a fee for Amazon to affix the sticker.
For most listings, the seller can choose to use the UPC code instead of Amazon assigning an FNSKU. Called "commingling", this is unwise because there is no way for Amazon to distinguish between its own inventory, your genuine inventory, and another seller's counterfeits. Amazon says that its inventory procedures still differentiate between sellers, but a) no one believes this and b) all the stated procedures would do in a case of, say, Seller 2's counterfeit item being shipped when Seller 1 makes a sale would be to potentially identify that Seller 2 is the source of the counterfeit, as opposed to avoiding shipping it in the first place.
Clearly, using only nine characters would have been asinine.
For everything I want to sell
No matter book or bathtub gel
There's one key thing in S-Q-L
I need, I need, I need, its ASIN
This is to differentiate it from their in store operations: DPCI - DePartment Class Item
Has this perhaps changed over time, are there older ASINs which are different between regions, but new ones refer to the same product everywhere?
Anyone know what the A.... ASINs that were mentioned in the article are/were used for?