[ale] Backup large files to span DVDs

[Jim Kinney]

That is so cool!!!!

Working everything under a 64k limit is amazing. 

On October 28, 2015 8:29:30 PM EDT, Alex Carver <agcarver+ale at acarver.net> wrote:
>On 2015-10-28 13:42, Jim Kinney wrote:
>> On Wed, 2015-10-28 at 14:46 -0400, James Sumners wrote:
>>>
>>> I am glad I do not work where you work. Redundancy doesn't imply
>>> corruption mitigation. And refusing to allow such to be implemented
>>> because the tool isn't "old" is asinine.
>>>
>> It's not that things are refused because they are new. It's rather
>they
>> are refused because they are not yet "well understood" and "mature".
>> Mil-Spec work is _always_ like that. 
>> Often, there are areas where software is never upgraded or changed
>> because the systems are never networked. Thus any problem can never
>be
>> fixed and the process that machine exists for _MUST_ be up at all
>> times. So, no "new hotness allowed".  Imagine being stuck in a world
>> where "new" was RHEL 5.
>
>I'll give a real world example that's happening right now.  One of the
>projects here is Voyager (you know the one with the two probes that
>exited the solar system and are now in interstellar space).  The last
>of
>the original project members (the project manager) has announced his
>retirement at 83 years old.
>
>Voyager wasn't expected to be operating past ten years after launch
>(long enough to reach the primary targets Jupiter and Saturn).  It was
>launched in 1977 but design and construction would have started in the
>very early 70's (mission concept, design and construction of this class
>is typically 6-10 years) which means the Voyager documents are now over
>40 years old.  It's also still classified as an active mission because
>it is still returning science data which means making sure the computer
>and instruments on board stay running.  Voyager's code is assembly with
>64 kilobytes of total operational program storage space on board (data
>is recorded to an 8-track tape).
>
>During the flights of the two Voyagers, many modifications to the code
>had to be made.  This involved, among other things, knowing very
>specific details about the instruments on board each one which turned
>out to have very subtle differences.  The code has to be rewritten from
>scratch every time because of the limited space.  It gets written on
>the
>ground, verified, then uploaded.
>
>Unfortunately, the data retention policies at the time were not very
>stringent.  Since the mission was expected to last only about 10 years,
>many documents were not updated and archived properly.  Engineers kept
>details in their heads because they would likely still be working
>beyond
>the end of the mission.  As the mission continued past its original
>endpoint, this quickly became a problem when changes needed to be made.
> Many of the engineers have died taking secrets about the spacecraft
>with them.  In other cases files have been lost to time because the
>were
>written in formats that no one knew how to interpret (work is ongoing
>to
>recover much of that data).  There's even a working replica of the
>computer in the mission office today where code is tested before
>upload.
> It has been running since 1979 and still needs to be maintained.
>
>It was because of this and other early projects (Explorer, Mariner,
>etc.) that the data usage, retention and archive policy was tightened.
>That included what software could be used and how generated data could
>be stored.  The entire intent is to maintain an accessible, functional
>history for scientists and engineers in the event we need to go back to
>old data for anything.  That happens very often.
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-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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