[omgps] collect feature requests

Laszlo KREKACS laszlo.krekacs.list at gmail.com
Tue Jun 30 23:32:39 CEST 2009

On Tue, Jun 30, 2009 at 10:40 PM, mqy<meng.qingyou at gmail.com> wrote:
> My test with omgps running shows no failure, with 26954 image files.
> You can add a swap file /partition then test again, to see if limited memory
> causes this problem. I've watched with `vmstat 1`, seen limited memory
> usage.
> Here is my clues:
> #1: max current of usb power supply is 500mA, with heavy CPU load, uSD card
> may not get enough power then fails to work.
> #2: Many people experienced the "lose partition problem" including myself, I
> can remember somebody asked that "why GPS hurt uSD card?".

Ok, I lied a bit. I only tested with tangogps.

But, it was reproducible. If the device freezed or I removed the battery, many
tile maps got unreadable. I couldnt even list some directories or cd into them!
(it rules out heavy CPU load, and not getting enough power)

I already wrote about it about a month ago:

So the problem really comes about the insane 75000 files (118MB).

I would really like to tar, ar, zip, etc the dirs containing the invidual tiles.
It seems an easy job! Would be much more managable, speed up
a lot the file copying (copying many small files is several magnitude slower!).

Current directory structure:

We could simply create an OSM/11/1102.tar file, containing those invidual
files. I bet it would be not slower. I could even imagine some speed boost.

Remember accessing invidual files on a sd card takes time. A lot.
You can try it for yourself, copy to a pendrive your ~/Maps directory.
Now tar the dir (Maps.tar) and copy that singly file to the pendrive.

The result is something like 40sec compared to 6-7min.

So please consider to implement this on-the-fly untaring capability.

Thank you,

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