[HN Gopher] Six Characters
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       Six Characters
        
       Author : Airplanepasta
       Score  : 81 points
       Date   : 2026-04-13 09:24 UTC (3 days ago)
        
 (HTM) web link (ajitem.com)
 (TXT) w3m dump (ajitem.com)
        
       | chrismorgan wrote:
       | Also not mentioned, they're not unique across time: six base-36
       | characters is only 2 billion possibilities, wouldn't surprise me
       | if the largest GDS would blow through the entire space within a
       | year.
       | <https://support.travelport.com/webhelp/smartpointcloud/Conte...>
       | suggests they get purged after a week, and recycled.
       | 
       | I wonder what fraction of the space is occupied at any given
       | time.
        
         | Procrastes wrote:
         | There used to be a story going around, possibly apocryphal,
         | that the process to reset them used to be entirely manual and
         | generally unknown to the rest of the organization. There was a
         | big problem the week the person who had that task retired.
         | Someone around here was probably there if it really happened
         | and can add some color.
        
       | hamburglar wrote:
       | Interesting post. One detail I don't see is how the ROE info
       | actually tells you what currency to convert to. I see the
       | exchange rate calculation but how do you know what the final
       | units are?
        
         | gregschlom wrote:
         | I suspect it's this part:
         | 
         | "This ticket was priced in GBP, not INR. Because the journey
         | originated in Manchester, the fare is denominated in the
         | currency of the origin country: the United Kingdom."
         | 
         | So: the currency is the one for the country of origin.
        
       | Mordisquitos wrote:
       | After reading the article, for some reason I am finding the
       | following fact profoundly distressing. Surely there are more than
       | 1000 active airlines worldwide!?
       | 
       | > _Every airline has a 3-digit IATA numeric code. 098 = Air
       | India. British Airways is 125. IndiGo is 526. These codes predate
       | the familiar 2-letter IATA codes (AI, BA, 6E): they were used
       | when teletypes could not reliably transmit letters and numbers
       | interchangeably._
        
         | ks2048 wrote:
         | IATA-registered airlines - it seems there are 370,
         | 
         | https://www.iata.org/en/about/members/airline-list/
        
         | lexicality wrote:
         | The IATA has 367 active airlines.
         | 
         | Bear in mind that this doesn't apply to charter airlines, only
         | public passenger ones.
         | 
         | Given there are about 200 countries in the world, you'd need 5
         | large airlines per country, which is a lot! Most of them don't
         | have any and rely on other countries. Still more have a single
         | national carrier.
        
         | addaon wrote:
         | Also, not every airline has a 3-digit code. e.g. Aero Republica
         | has the two-alphanum designator P5, but doesn't have a 3-digit.
        
         | decimalenough wrote:
         | Two-letter codes are assigned to anybody on request, but three-
         | digit codes are assigned only to full IATA members.
         | 
         | The three-digit code is used primarily for ticketing (it's the
         | first three digits of a ticket number), and as an airline you
         | only really need it if you're going to do complex interop
         | things like ticketing another airline's flights. Most low cost
         | carriers like Ryanair are not IATA members, and even Southwest
         | only joined last year.
        
       | croisillon wrote:
       | Related: 49 comments, 5 days ago
       | https://news.ycombinator.com/item?id=47730712
        
       | Procrastes wrote:
       | A half-joking comment I once heard from someone who was part of
       | the group that established the NUC. It stood for "Not US
       | Currency," but tracks the dollar because that compromise was the
       | only thing everyone could agree on. The first stablecoin.
        
         | bbanyc wrote:
         | I wonder why they didn't go with the IMF Special Drawing Right,
         | which is used in many other international contexts. (Including
         | aviation - the liability limits under the Montreal Convention
         | are in SDRs.)
        
       | NewsaHackO wrote:
       | Very interesting article. However, almost didn't open due to the
       | vague title. I was expecting something about short DOS names
        
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