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posted by janrinok on Saturday January 08, @08:10PM   Printer-friendly
from the PC-introns dept.

https://www.os2museum.com/wp/unidentified-pc-dos-1-1-boot-sector-junk-identified/

Anyone trying to disassemble the PC DOS 1.1 boot sector soon notices that at offsets 1A3h through 1BEh there is a byte sequence that just does not belong. It appears to be a fragment of code, but it has no purpose in the boot sector and is never executed. So why is the sequence of junk bytes there, and where did it come from?

The immediate answer is "it came from FORMAT.COM". The junk is copied verbatim from FORMAT.COM to the boot sector. But those junk bytes are not part of FORMAT.COM, either. So the question merely shifts to "why are the junk bytes in FORMAT.COM, and where did they come from?"

It is not known if anyone answered the question in the past, but the answer has been found now, almost 40 years later—twice independently.


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  • (Score: 0) by Anonymous Coward on Sunday January 09, @02:38PM (1 child)

    by Anonymous Coward on Sunday January 09, @02:38PM (#1211244)

    Now if you'll excuse me, I have to get back to read the newspaper from 1979, yes I got a bit behind

  • (Score: 1, Insightful) by Anonymous Coward on Sunday January 09, @04:54PM

    by Anonymous Coward on Sunday January 09, @04:54PM (#1211259)

    It is useless and out of date junk, but that's also how I feel about any web-related technologies I am forced to learn. I've got to know it, but it very, very soon becomes obsolete knowledge. Makes it hard to get motivated to learn any more than is absolutely necessary to get the job done.