Hi Keith and list,
I myself wonder about this, but I have some hypotheses:
* It might be due to the limitations imposed by the actual bootloader - in
other words, th upgrade software might have been programmed to use the
maximum of 512 MB cards because the hardware cannot support larger cards.
For example, if we use 1 GB card to upgrade our units, the bootloader cannot
recognize changes e.g. differences between sector size, inability to put
booting information as accurately as possible, and so forth.
* It might be due to sector limitations. A sector is a location where a part
or a whole file is stored. In other words, the sector sizes between 512 MB
and 1 GB card is different that only smaller sector size can be used. For
example, if we have a card which has sector size of 512 characters and if
the bootloader requires each sector to be, say, 1024 bytes, then the upgrade
software cannot write the whole thing and needs to divide the data in half
in order to put those into the two availible sectors.
* It might be due to the nk.bin/nk.rom image itself. Because an image like
this - typically the ones which needs to "boot up," - is integrated with the
target hardware, and due to the conditions on Flash and RAM Disk (KeySoft
System Disk) such as sector size and boot blocks, the upgrade software might
prevent the user from using cards larger than 512 MB.
These are the hypotheses that I can think of. But I'm about 90% confident
that it might be related to hardware in question - in other words, the
problem might arise due to hardware limitations for about 90% of the time.
(unless there is evidence to debunk this null hypothesis, in which the
alternate hypothesis is chosen: problem caused by software).
Cheers,
Joseph
----- Original Message -----
From: "Keith Bundy" <[EMAIL PROTECTED]>
To: "Alana Jovanovski" <[EMAIL PROTECTED]>;
<[email protected]>
Sent: Sunday, December 16, 2007 5:22 PM
Subject: Re: [Braillenote] Installing upgrade using different memory card
I am curious. Why is the size of the SD card limited to no larger than 512
mb for an installation or upgrade?
----- Original Message -----
From: "Alana Jovanovski" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, December 16, 2007 7:22 AM
Subject: [Braillenote] Installing upgrade using different memory card
Hi List,
I am not sure if this message got through, but I was wondering if you
could
install upgrades using a different memory card that is between 64 and 512
megabytes in size. I have a PC card that is about 64 megabytes in size.
Apologies for the continuous questions relating to this upgrading matter.
Alana
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