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2016 Bug Hits Text Messages, Payment Processing

Posted by Soulskill on from the y2k16-has-more-characters-than-2016 dept.

An anonymous reader writes "It seems some systems are suffering from a Y2K16 bug. When 2009 ticked over to 2010, some Australian EFTPOS machines skipped to the year 2016. Coincidentally, some Windows Mobile users are also having issues with their new year SMSes coming from 2016. What function could cause this kind of error?"

21 of 340 comments (clear)

  1. Microsoft by sopssa · · Score: 5, Informative

    Seems Microsoft is supplying some code for EFTPOS machines that is common with Windows Mobile, so it's most likely the same bug in both.

    1. Re:Microsoft by sopssa · · Score: 3, Informative

      Yes they do (almost in every atm actually).

  2. 10 hex is 16 decimal by Anonymous Coward · · Score: 5, Informative

    Could be botched string parsing. Could be binary coded decimals interpreted as binary numbers: BCD encodes two decimal digits in the high and low nibbles of a byte. Therefore BCD 10 is 0001 0000 in binary, which is 16 in decimal.

    1. Re:10 hex is 16 decimal by nycguy · · Score: 5, Informative

      This is almost certainly what it is. The year is stored in an SMS message as a two-digit BCD value, according to this spec. (Click on the link for the "timestamp" field.) Some phones must be treating it as a hex field. (Note that most other fields in the SMS message are in hex.)

    2. Re:10 hex is 16 decimal by Pembers · · Score: 4, Informative

      The specification for the SMS message format pre-dates Y2K by about 15 years. I came across it in 1995 (and thought it was useless - what sort of idiot would try to fit a message into 160 characters? And who would want to type it on a 12-button keyboard?). Where I worked, nobody worried about Y2K until about 1998.

      --

      Just another wannabe fantasy novelist...

    3. Re:10 hex is 16 decimal by clone53421 · · Score: 2, Informative

      It makes a lot more sense in little endian.

      --
      Alexander Peter Kristopeit bought his basement from his mommy for one dollar.
    4. Re:10 hex is 16 decimal by Anonymous Coward · · Score: 4, Informative

      The endianness may make it more sensible. If you have 0x12345678 represented using the correct endianess (the Intel one, not the Sun one), it'll be stored as 0x78563412. Using reverse nibble notation, it'll be 0x87654321.

      But as far as I remember, it is caused by oldold ties to the 4004, which was a 4-bit CPU, inherited via the 8008 and 8080 by the 8086 and 8088.

    5. Re:10 hex is 16 decimal by Anonymous Coward · · Score: 1, Informative

      But IS it harder to read? For a human, yes. But, for a computer this makes perfect sense for a little endian computer. On a little endian machine (i.e. Intel x86), the bytes are stored sequentially from memory address zero up. If you grab large a 32-bit number and print it, you might see would see x0000000F. This makes things very easy for computer because a small number can be read from the same address as a 8 bit, 16 bit, and up without any need to adjust the offset (i.e. 0F = 15, 0F00 = 15, 0F000000 = 15). A big endian machine will make things follow Arabic numerals (i.e. 0F = 15, 000F = 15, 0000000F = 15). To correctly read a number, you have to adjust your offset to match the size of your number.

      Now, we can also think about these mindsets when dealing with nibbles. A swapped nibble set means that for a computer each BCD encoded number becomes directly addressable on a little-ending machine straight up through memory. All I have to know is starting byte and the number of digits so I know when to stop. Fifteen years ago, saving code space was more important than being human readable. Swapped nibble encoding meant a simple algorithm to get each decimal:

      byte_address = byte_address_start + decimal_count >> 2
      byte = *byte_address -> byte_type
      decimal = decimal_count mod 2 ? byte AND F0 >> 4 : byte AND 0F

      Some machines have instructions in the processor to handle this type of behavior innately.

  3. Re:Some kind of... by GrumpySteen · · Score: 1, Informative

    I think you mean hexadecimal. When 10 is interpreted as binary, it's 3 not 16.

  4. Re:Some kind of... by Anonymous Coward · · Score: 5, Informative

    I don't think you quite have the hang of binary (10 would be 2, not 3).

  5. Re:Some kind of... by Anonymous Coward · · Score: 1, Informative

    he meant binary coded decimal you clod

  6. Re:Some kind of... by RichardJenkins · · Score: 2, Informative
    • The decimal number '10' would be encoded in BCD as '1010 0000'
    • '10' is not a valid BCD bitstring
    • When writing in base 2 (binary), '10' is the same number as '2' when writing in base 10
    • putting '0x' before a number indicates that it is written base 16 (hexadecimal)
    • '0x10' is 16 in decimal
  7. Re:Some kind of... by msauve · · Score: 5, Informative

    No, I meant exactly what I said. I didn't say 0b01. 0x10 is the hexadecimal notation for "00010000" binary, which is 16 decimal.

    I used 0x10 because that's standard ANSI C (and ECMA-334 C#), and C is what seems to be spoken on /.. 0b00010000 is non-standard (but allowed by some compilers).

    --
    "National Security is the chief cause of national insecurity." - Celine's First Law
  8. Re:Some kind of... by clone53421 · · Score: 4, Informative

    Let me see if I can straighten it out, then.

    0x10 is a hexadecimal number, 0001 0000 binary, 16 decimal.
    0x10 is a BCD number, 0001 0000 binary, 10 decimal.

    (BCD is an encoding system, not a base system. In hex or binary it’s given in encoded form, but in decimal it’s given in decoded form.)

    --
    Alexander Peter Kristopeit bought his basement from his mommy for one dollar.
  9. Re:Some kind of... by xaxa · · Score: 3, Informative

    0x10 means 0001 0000.

    0001 0000, if that's a binary number, means decimal 16
    0001 0000, if that's binary coded decimal (BCD), i.e. decimal 0-9 represented as 0000 to 1001, means decimal 10.

    (If 0001 0000 was little endian (with 4-bit groupings) it would mean binary 1)

    1234 in binary (4D2 in hexadecimal) is 0000 0100 1110 0010
    1234 in BCD is 0001 0010 0011 0100

  10. Re:Some kind of... by Anonymous Coward · · Score: 1, Informative

    Give him a break. This whole thread is made of such epic fail that it could only be unforged in Mount Doom.

    10 is 3 in binary indeed...

    Let's try this again.

    In binary...

    Binary 00 = Decimal 0
    Binary 01 = Decimal 1
    Binary 10 = Decimal 2
    Binary 11 = Decimal 3

    BCD is something different. But you said binary. And by the way, I'm not aware of any BCD format in which 10 = 3.

  11. Re:WHY DO PEOPLE INSIST UPON REPLACING THE FIRST Z by Anonymous Coward · · Score: 1, Informative

    Parent makes no sense.

  12. no that's a Y210 bug by rubycodez · · Score: 3, Informative

    Y bugs are named for the year in which they occur, not the year they jump....otherwise Y2K would have been Y1.9K, or even better YMCM

  13. Re:* points finger at Duct Tape Programmers by Blakey+Rat · · Score: 2, Informative

    It is just that I do also think the type of error the 2016 bug is can indeed be attributed to the "duct tape programming" attitude.

    But that's exactly what Jamie *isn't* talking about. He never said anything about not designing the system, or doing the design ad-hoc, all he's saying is two things:

    1) If your code is too complex, uses too many obscure language features, or has a structure that can't easily fit in the average person's head, it's likely to be more buggy since some of your team will never fully understand it. (Or, if they do now, future maintainers may not.) Basically, the coding equivalent to Keep It Simple, Stupid.

    2) The number one feature of any application is "it shipped." It doesn't matter how great your program is if it's vaporware.

    Neither of those two points have anything at all to do with this bug.

    The word "duct-tape" leads people to think that the philosophy has something to do with coding by the seat of your pants. "Oh this function isn't designed right, I'll just put a couple globals in this file to get the right params" or something like that. Not only is that not in the interview with Jamie, but even Joel's article doesn't say anything like that.

    When you choose a name like "duct-tape programmer" you're basically guaranteeing that people are going to misread the article, as I believe you have. Anyway, best to ignore that particular work of Joel's and go straight to the interview with Jamie in the first place, if you want the real story.

    This particular bug is simply a case of misreading a confusing spec in a subtle, and nobody catching it for years. That could happen regardless of your method or philosophy. Anybody coming into this and saying "oh unit tests would have nailed this!" or "oh that would never happen with Scrum!" is just cheerleading their favorite concept.

    --
    Comment of the year
  14. Re:Some kind of... by Vintermann · · Score: 4, Informative

    > (a leftover relic from the mainframe era that needed to die over a decade ago)

    No no no. Binary coded decimal is necessary and useful. When you divide 1 by 10, you should get 0.1, not 0.10000000000000001 (which is what you get if you for instance open up a python interpreter and ask for 1.0 / 10.0).

    Monetary amounts, and currency conversion rates are examples of something you should never, ever use standard binary floats for.

    Fact: Many major databases use some form of BCD for representing currency values. Enough so that IBM added a dedicated decimal FPU for their power6 series - it's so common on business database servers that it actually saves a lot.

    --
    xkcd is not in the sudoers file. This incident will be reported.
  15. Re:Some kind of... by Enter+the+Shoggoth · · Score: 2, Informative

    > (a leftover relic from the mainframe era that needed to die over a decade ago)

    No no no. Binary coded decimal is necessary and useful. When you divide 1 by 10, you should get 0.1, not 0.10000000000000001 (which is what you get if you for instance open up a python interpreter and ask for 1.0 / 10.0).

    Monetary amounts, and currency conversion rates are examples of something you should never, ever use standard binary floats for.

    Fact: Many major databases use some form of BCD for representing currency values. Enough so that IBM added a dedicated decimal FPU for their power6 series - it's so common on business database servers that it actually saves a lot.

    Here's a useful document from Sun on the matter (warning: pdf). The title is absolutely spot on: "What Every Computer Scientist Should Know About Floating-Point Arithmetic"

    --
    Andy Warhol got it right / Everybody gets the limelight
    Andy Warhol got it wrong / Fifteen minutes is too long.