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From: Paul on 20 Jun 2010 09:05
Man-wai Chang wrote:
>> This allows a capacity of 4 GB. The main problem is that some
>> of the card readers support only a block (or, sector) size of 512 bytes,
>> so greater than 1 GB non-SDHC cards may cause compatibility difficulties
>> for users of such devices."
>> So up to 1GB, byte addressing, with 512 byte blocks, should always work.
>> Devices bigger than 1GB, may need larger sector size, like 2048 bytes.
>
> You meant if I formatted a 4G SD card using 512-byte blocks, the old
> card reader might be able to read it like it did with older 1G SD cards?

I don't think you can "format" the thing to fix it.

http://en.wikipedia.org/wiki/Talk:Secure_Digital

"Some SD-card reader systems does not correctly process the READ_BL_LEN
parameter. And therefore will not correctly recognise some cards
(esp 2G and 4G cards in std sd-card readers). But this is NOT the
same as saying >1GB - 4GB standard sd-cards doesn't exist or will not work."

The fields are c_size, c_size_mult, read_bl_len. Once the c_size and c_size_mult
are approaching their maximum value, the only way to declare a larger SD, is to
use a larger read_bl_len.

It appears Sandisk has on occasion released info in document form, and this
is just one example of showing some of those register values. In this particular
example, the device has a small enough capacity, that a 512 byte read_bl_len
can be used.

http://www.cs.ucr.edu/~amitra/sdcard/ProdManualSDCardv1.9.pdf

Paul
From: Man-wai Chang on 20 Jun 2010 09:41
> http://en.wikipedia.org/wiki/Talk:Secure_Digital
> http://www.cs.ucr.edu/~amitra/sdcard/ProdManualSDCardv1.9.pdf

Thank you for the time.
From: Ian D on 20 Jun 2010 12:12

"Man-wai Chang" <toylet.toylet(a)gmail.com> wrote in message
news:hvl5qe$dvg$1(a)news.eternal-september.org...
>> http://en.wikipedia.org/wiki/Talk:Secure_Digital
>> http://www.cs.ucr.edu/~amitra/sdcard/ProdManualSDCardv1.9.pdf
>
> Thank you for the time.

If it's a built in card reader, a driver update may allow the
use of 2GB cards. I have a 5 year old HP laptop that
initially wouldn't recognize 2GB SD cards. A driver update
fixed that.


From: Man-wai Chang on 20 Jun 2010 12:33
> If it's a built in card reader, a driver update may allow the
> use of 2GB cards. I have a 5 year old HP laptop that
> initially wouldn't recognize 2GB SD cards. A driver update
> fixed that.

It's an Oregon Scientific CU328 indoor phone.
From: Paul on 20 Jun 2010 15:24
Man-wai Chang wrote:
>> If it's a built in card reader, a driver update may allow the
>> use of 2GB cards. I have a 5 year old HP laptop that
>> initially wouldn't recognize 2GB SD cards. A driver update
>> fixed that.
>
> It's an Oregon Scientific CU328 indoor phone.

1GB SD are only $6.25 each. Buy a handful and you're all set.
Each one has more capacity than a CDROM.

http://www.newegg.com/Product/Product.aspx?Item=N82E16820208042

Paul
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