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Forum Index : Microcontroller and PC projects : Long file-names support?
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9066 |
Hi all.  Am I correct in assuming that LFN support will NEVER be introduced into the MM+ series firmware, simply because LFN is a Microsoft technology and would require a license to implement? As Microsoft give discounts to no-one, this would probably explain why all embedded systems still use the old 8-dot-3 filenames, yes? IE: Even if you COULD write a Cfunction to allow access to an SD card with LFN, it would not be written as the licensing cost from Microsoft to use LFN would basically rule that out. Why am I asking? The system that got fried recently in the big lighting strike, used the ALFAT SD module on a PICAXE controller, and the uALFAT module has licensed LFN support, and the nodes on the network transmit a 12-byte filename reference to the system. In an idea world, when porting this system over to the MM+, I would like to retain the LFN, but I don't think that will ever be a possibility, so I am now working on a standard filename reformatting process, that will strip out four specific filename characters, so that I can address the nodes with standard 8-dot-3 filenames on the SD card. IE: The node still transmits the 12-byte filename reference, but the MM+ truncates it to 8-dot-3, THEN asks the SD card for THAT filename. Initial tests reveal that this does work just fine, but before I go any further, and with so many things being developed in the Cfunction world for the MM+, I thought I should just get confirmation one way or the other on this. Smoke makes things work. When the smoke gets out, it stops! |
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Geoffg Guru  Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
I am not sure about the licensing system (I heard the same story as you) but there is already LFN support in the Microchip SD card libraries that are used in the Maximite/Micromite. The only problem is that I was never able to get that part to work. I have a long term aim to replace the SD support with a more modern and easier to use library (there are a few out there) and then (hopefully) we will have LFN support as well as multiple SD cards, etc. Knowing the speed at which Peter works I would not be surprised if he also popped up with an implementation (he recently implemented an alternate USB library). Geoff Geoff Graham - http://geoffg.net |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9066 |
Interesting. I'll wait and see if Peter will spare a few seconds for comment here, if he has time.  In the meantime, I will proceed with the concept of truncating the filenames to 8-dot-3. This is not difficult with the help of MID$, and knowing exactly which filename bytes to drop..... This is likely to be a Christmas holiday porting project, so I am not in any hurry at this stage for LFN, when I do have a work-around solution to this. But it would certainly be nice to think that LFN might be supported - MIGHT. I figured that the Microsoft licencing thing would kill that idea off before it even gets started. I might be totally wrong there, but I expect that LFN use is still restricted by Microsoft. Smoke makes things work. When the smoke gets out, it stops! |
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