Maximum size of SD card

[AGM]

Could someone please explain to me why in the instruction manuals for some devices it says that the maximum size of SD card that can be used is 256MB. I've go a mobile phone and the car stereo system which take SD cards to play mp3's, both have a limit of 256MB. It would be nice to be able to use a bigger size memory card in the car. I know the obvious answer is to get a bigger card and try it, but it would be nice to know the reason if there is a valid reason. Thanks in advance. AGM

[Terryvi]

It has to do with the size of the address register for the CF card. For example if you have an 8 bit register you can store addresses from 0 to 255. To address 256 million addresses would take an address register of ..... my head just exploded

[Terryvi]

Actually, it sounds like your phone and stereo have a 28 bit address register which will hold addresses from 0 to 268,435,455 or 256 meg.

[DudeZXT]

Maximum size I've found (technology-wise) is currently 4Gb.

[coach_ng]

Could someone please explain to me why in the instruction manuals for some devices it says that the maximum size of SD card that can be used is 256MB. I've go a mobile phone and the car stereo system which take SD cards to play mp3's, both have a limit of 256MB. It would be nice to be able to use a bigger size memory card in the car. I know the obvious answer is to get a bigger card and try it, but it would be nice to know the reason if there is a valid reason. Thanks in advance. AGM

which car stero do you have?

[AGM]

Thanks Terryvi for that information.

In answer to coach_ng question, I have the Audi's Navigation System Plus (RNS-E) which has the Multi-Media System built into it. It takes 2 SD cards, each 256MB card holds about 4 albums worth of music in mp3 format. AGM

[Tahoe Trekker]

Could someone please explain to me why in the instruction manuals for some devices it says that the maximum size of SD card that can be used is 256MB. I've go a mobile phone and the car stereo system which take SD cards to play mp3's, both have a limit of 256MB. It would be nice to be able to use a bigger size memory card in the car. I know the obvious answer is to get a bigger card and try it, but it would be nice to know the reason if there is a valid reason. Thanks in advance. AGM

I use a 1GB SD and a 4GB CF... no problems!

[coach_ng]

I use a 1GB SD and a 4GB CF... no problems!

he's not asking about flash media in your axim rather flash media in his phone and car stereo

[AGM]

Just to let you know, I managed to borrow a 512MB card and tried it in the car and it works fine. AGM

[Terryvi]

Just for my curiousity, did you fill the 512 meg card all the way up, and did you try to play a song from each album? The reason I ask is the 512 meg card could work fine until you try to play something in the second 256 meg of the card.

[AGM]

Yes I managed to fill the whole card, all but 46KB. It took just over 9 albums. Clearly didn't manage to listen to all the tracks last night, but sampled few tracks off each album and it seems to work fine. Next step is to get a card and try it over a longer period. Thanks for your help. AGM