Because we have 8 bit bytes we are familiar with the famous or obvious cases multiples-of-8-bits ran out, and those cases sound a lot better with 12.5% extra bits. What's harder to see in this kind of thought experiment is what the famously obvious cases multiples-of-9-bits ran out would have been. The article starts to think about some of these towards the end, but it's hard as it's not immediately obvious how many others there might be (or, alternatively, why it'd be significantly different total number of issues than 8 bit bytes had). ChatGPT particularly isn't going to have a ton of training data about the problems with 9 bit multiples running out to hand feed you.

It also works in the reverse direction too. E.g. knowing networking headers don't even care about byte alignment for sub fields (e.g. a VID is 10 bits because it's packed with a few other fields in 2 bytes) I wouldn't be surprised if IPv4 would have ended up being 3 byte addresses = 27 bits, instead of 4*9=36, since they were more worried with small packet overheads than matching specific word sizes in certain CPUs.

Author here. Actually I doubt we'd have picked 27-bit addresses. That's about 134M addresses; that's less than the US population (it's about the number of households today?) and Europe was also relevant when IPv4 was being designed.

In any case, if we had chosen 27-bit addresses, we'd have hit exhaustion just a bit before the big telecom boom that built out most of the internet infrastructure that holds back transition today. Transitioning from 27-bit to I don't know 45-bit or 99-bit or whatever we'd choose next wouldn't be as hard as the IPv6 transition today.

The IPv4 networking case is especially weird to think about because the early internet didn't use classless-addressing before CIDR.

Thinking about the number of bits in the address is only one of the design parameters. The partitioning between network masks and host space is another design decision. The decision to reserve class D and class E space yet another. More room for hosts is good. More networks in the routing table is not.

Okay, so if v4 addresses were composed of four 9-bit bytes instead of four 8-bit octets, how would the early classful networks shaken out? It doesn't do a lot of good if a class C network is still defined by the last byte.

LLM dren also isn't going to provide anything on how wildly different the home computer revolution would have been with twice as big character ROMs; the personal computer revolution would have been with twice as big code pages 437, 850, and 1252 and an extra CGA attribute bit; the BBS era would have been with 9N1 telecommunications; ECMA-48 and ECMA-35 would have been with space for the C1 control characters with no need for alternative forms; ASCII and EBCDIC would have been without need for the national variants and room for some accented characters; and even how different the 6502 instruction set would have been.

With so many huge changes like those the alternate history by today would be far diverged from this universe.

The knock-on effect of EBCDIC having room for accented characters would have been the U.S.A. not changing a lot of placenames when the federal government made the GNIS in the 1970s and 1980s, for example. MS-DOS might have ended up with a 255-character command-tail limit, meaning that possibly some historically important people would never have been motivated to learn the response file form of the Microsoft LINK command. People would not have hit a 256-character limit on path lengths on DOS+Windows.

Teletext would never have needed national variants, would have had different graphics, would have needed a higher bitrate, might have lasted longer, and people in the U.K. would have possibly never seen that dog on 4-Tel. Octal would have been more convenient than hexadecimal, and a lot of hexadecimal programming puns would never have been made. C-style programming languages might have had more punctuation to use for operators.

Ð or Ç could have been MS-DOS drive letters. Microsoft could have spelled its name with other characters, and we could all be today reminiscing about µs-dos. The ZX Spectrum could have been more like the Oric. The FAT12 filesystem format would never have happened. dBase 2 files would have had bigger fields. People could have put more things on their PATHs in DOS, and some historically important person would perhaps have never needed to learn how to write .BAT files and gone on to a career in computing.

The Domain Name System would have had a significantly different history, with longer label limits, more characters, and possibly case sensitivity if non-English letters with quirky capitalization rules had been common in SBCS in 1981. EDNS0 might never have happened or been wildly different. RGB 5-6-5 encoding would never have happened; and "true colour" might have ended up as a 12-12-12 format with nothing to spare for an alpha channel. 81-bit or 72-bit IEEE 754 floating point might have happened.

"Multimedia" and "Internet" keyboards would not have bumped up against a limit of 127 key scancodes, and there are a couple of luminaries known for explaining the gynmastics of PS/2 scancodes who would have not had to devote so much of their time to that, and possibly might not have ended up as luminaries at all. Bugs in several famous pieces of software that occurred after 49.7 days would have either occurred much sooner or much later.

Actual intelligence is needed for this sort of science fiction alternative history construction.

Well, there should be half as many cases of multiples-of-9-bits ran out than for multiples-of-8-bits.

I don't think this is enough of a reason, though.

There is certainly a well known bias or fallacy that describes this