[gentoo-user] Re: OT: old farts slum_code enforcement

[Grant Edwards]

On 2014-09-15, Alan McKinnon <alan.mckinnon@×××××.com> wrote:

> My favourite Fortran story:
>
> One of the Mariner spacecraft yonks ago was sent a routine regular
> course correction. It flew off at some wild angle and was never seen
> again, and because the antenna was pointing in the wrong direction
> comms could not be re-established. Oops. Expensive spacecraft down
> the drain....
>
> The bug was eventually trace to a comma instead of a period in some
> Fortran code (made a huge difference). Note that many code reviews
> missed the bug, and the compiler accepted it as valid syntax

While that is a good story, Wikipedia refers to it as "a
legend", and NASA explicitly identifies a different cause.
According to NASA failure was caused by faulty beacon equipment
combined with an omitted hyphen in a data editing program.

http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=MARIN1:

   The failure was apparently caused by a combination of two factors.
   Improper operation of the Atlas airborne beacon equipment resulted
   in a loss of the rate signal from the vehicle for a prolonged
   period. The airborne beacon used for obtaining rate data was
   inoperative for four periods ranging from 1.5 to 61 seconds in
   duration. Additionally, the Mariner 1 Post Flight Review Board
   determined that the omission of a hyphen in coded computer
   instructions in the data-editing program allowed transmission of
   incorrect guidance signals to the spacecraft. During the periods
   the airborne beacon was inoperative the omission of the hyphen in
   the data-editing program caused the computer to incorrectly accept
   the sweep frequency of the ground receiver as it sought the vehicle
   beacon signal and combined this data with the tracking data sent to
   the remaining guidance computation. This caused the computer to
   swing automatically into a series of unnecessary course corrections
   with erroneous steering commands which finally threw the spacecraft
   off course.  
   
-- 
Grant Edwards               grant.b.edwards        Yow! I want the presidency
                                  at               so bad I can already taste
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