Why the Delay in v5.0?

It’s all about the data.

5.0 operates standalone , without any internet connectivity.  That means all the sat. imagery and elevation data are local.  The source data devolves into tens of millions of files and many terabytes of data.  Once that’s been created it needs to get reprocessed and shrunk enough to work on a tablet.  The goal is the elevation data match the resolution of the imagery, with the threshhold target resolution for Symbolic Flight 5.0 being 1 meter.

Resolving all this so 5.0 gives an accurate, photorealistic view of where you are in the world has posed several unanticipated data processing challenges.

The good news is they are resolved.

4 machines are happily crunching millions of fils to a 12TB RAID, then piping and squeezing it back to a few GB of final data.

I really do intend this to ship before New Years.

Paul

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Millions of Windows Files Solution

PROBLEM: NTFS brings disk access to its knees when large numbers of files are created.  The problem is not simply the absolute number of files, it is most likely file naming conventions leading to a massively unbalanced B+ tree in the MasterFileTable [MFT] The solution is subfolders.

In my case it was caused by the quadkey devolution of global sat imagery and digital elevation data into files named 0100123.dem, 01001230.dem,010012301.dem, etc.  The filename depth corresponds to the quadkey LOD making the names themselves highly recursive.  At LOD 12 that’s 256k files for the northwest quadrant of the planet, a number that increases by a factor of 4 for each higher level. At LOD 15 and higher the number of tiny files for even a one degree band of information becomes considerable enough to choke Windows I/O.

Try to write them all in a single folder and Windows comes to a crawl, with the directory I/O processing eating several seconds per file, even on an SSD.

I suspect the hashing of the filenames results in a massively unbalanced B+ tree, which is the central structure of the Master File Table.  In NTFS this file contains a reference to every file on the disk.  There might be other issues, size of the MFT, fragmentation of the MFT–a defrag will fix that in Vista or beyond–but they pale compared to the B+ tree problem.

SOLUTION: Structured nested subfolders so the files get distributed in a fashion that results in more balanced hashing.  In my case it was subfolders treed according to the quadkey. This not only cuts the absolute number of files per folder, it significantly shortens the number of leaves on the last branch of the B+ tree.

I/0 resumes normal pace–which still sucks, after all these years, and gets charged to Windows  System Idle Process. But that is another story.

Paul

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Symbolic Flight 4.0 Release Pending…

Expected release Wednesday, Dec 1st.

Symbolic Flight $89 [GPS only. Airports, Runways, Airspace, Obstacles]

Symbolic Flight Pro $249 [supports FSX, eGyro, XRX and Additonal IFR Data: Navaids, Waypoints, Victor and Jet Airways, Transitions and Approaches]

Hello Virtual Earth 3D! [and Goodbye Google Earth]

New, clean and simple design. Twice the performance. Half the memory.

Forecast cloud layers so realistic you’ll think you are looking at a live camera.

Touch the symbols and they’ll tell you about themselves.

Create custom waypoints with a single mouse click.

Read the manual.

Back to work….

Posted in Uncategorized. Leave a Comment »

Symbolic Flight 4.0 Release Pending…

Expected release Wednesday, Dec 1st.

Symbolic Flight $89 [GPS only. Airports, Runways, Airspace, Obstacles]

Symbolic Flight Pro $249 [supports FSX, eGyro, XRX and Additonal IFR Data: Navaids, Waypoints, Victor and Jet Airways, Transitions and Approaches]

Hello Virtual Earth 3D! [and Goodbye Google Earth]

New, clean and simple design. Twice the performance. Half the memory.

Forecast cloud layers so realistic you’ll think you are looking at a live camera.

Touch the symbols and they’ll tell you about themselves.

Create custom waypoints with a single mouse click.

Read the manual.

Back to work….

Posted in Uncategorized. Leave a Comment »

Symbolic Flight Offers ‘Perpetual VFR’ with the latest 3.10 Release.

Version 3.10 of Symbolic Flight is now available with full support for the eGyro and eGyroGC electronic atttitude reference devices, both available in our online store. These very affordable, palm-sized devices add pitch, roll, and in the case of the GC, integrated WAAS GPS, data to Symbolic Flight via USB.

No other aviation product, at any price, offers these advanced capabilities:

  • Fly with 3D, photorealistic portable synthetic vision, WAAS GPS and inertial guidance.
  • Flight Plan and PreFly in Google Earth anywhere on Earth.
  • Flight Train coupled to Microsft Flight Simulator X anywhere on Earth.
  • See the latest FAA data in 3D, including charts, updated ever 28 days–global aviation data updated every six months.
  • Run on almost any Windows PC made in the last 5 years.

Symbolic Flight 3.1 retails for $249 and includes a one year data subscription and is available for purchase and electronic download at our online store..

The eGyro IMU retails for $595 and the eGyroGC for $995. Both are available in our online store.

Combine Symbolic Flight 3.1 with an eGyroGC and the Motion Computing J3500 and you have the best, sunlight readable, full synthetic vision capability on the planet in you cockpit for under $5000.

Paul Mace