A key parameter that isn't discussed is the likely life expectancy of the stored data. Clearly #1 (stone) wins hand down. It is still accessible thousands of years later without special instrumentation. The next step (which wasn't shown) is paper. It also can be read thousands of years later without special instrumentation. After that the story is much less encouraging. By my best guess, 5 of the memory technologies fail in archival storage because they lose memory without power (#3, 4, 5, 12, 14). Five more are no longer accessible because the technologies have been retired (#2, 6, 7, 8, 13). That leaves 4 to consider: the hard disk drive (9), the CD (10), and the flash (11) USB thumb drive (15). Today they seem safe - but it wasn't long ago that IBM cards, magnetic tapes, 8" floppies, 5.25" floppies, 3.5" floppies were considered universibly accessible. Most modern home computers can access none of them without special adapters. Powering and interfacing to old disk drives can be a challenge. From our present vantage point CD's seem universal but there are reports that the data may have a life expectance of less than 10 years. Also the availability of readers seems to be waning in newer devices. USB thumbdrives are certainly the current fad - but I have no doubt that the next technical wave will sweep them away as well. For the time being for archival storage, our two choices are paper (I'll concede the low data density of stone makes it impractical) and aggressive backup on electronic media that is constantly rolling the data (and the reading tools)to current storage technologies and equipment. A high overhead process. Our ancestors did much better with archival storage than we're managing.
"MT4C1024 one-mebibit dynamic random access memory (DRAM)"
And to explain the title, a coworker and I had a 20 minute argument with a hardware manager about the execution of our program. We assured him the program would execute within the 77 millisecond window between interrupts and he argued that our program could not be that fast.
At the end of it he asked, "What are them thar milli-seconds?"
NASA's Orion Flight Software Production Systems Manager Darrel G. Raines joins Planet Analog Editor Steve Taranovich and Embedded.com Editor Max Maxfield to talk about embedded flight software used in Orion Spacecraft, part of NASA's Mars mission. Live radio show and live chat. Get your questions ready.
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