Originally Posted by Dr.Strange
I have several SD card issues that hopefully someone can help me with.
First, I have an 8gb card, but only 7.3 of it is accessable. I have a micro SD card reader, and Gparted. Re-formatted the card a couple of times, and it always comes up as 7.3gigs.
Second, when I rooted my phone, I used the Recovery image Ivanmmj has in the stock 1.5 to root thread here on this forum. Shortly after, I think when I flashed ClockworkMod Recovery, I lost the ability to get into recovery by holding volume up and power. Only volume down and power gets me into a recovery state.
Third, I went into ADB and entered some commands from other places to do stuff to the Sd card, but one command still lingers when I do backup or restores:
E:can't mount /dev/block/mmcblk0p2 No such device.
Either that command is blocking off a section of my SD card, or the card just has a bad sector... Any ideas guys?
There is nothing wrong with your SD card.
Hard drive, SD card, and USB thumbdrive manufacturers typically define megabytes, gigabytes, etc as incrementing by powers of 1000. (so 1GB = 1000MB)
Most operating systems & software define megabytes, gigabytes, etc as incrementing by powers of 1024. (so 1GB = 1024MB)
So according to the manufacturer, your SD card has a capacity of 8GB (8000MB)
According to any operating system (Android, Windows, OSX, Linux, etc), your card has a capacity of 7.8GB (8000MB / 1024)
When you format ANY storage medium (hard drive, SD card, etc), the stated capacity of the device and the available capacity will not be the same.
To make matters worse, some of that 8GB/7.8GB (depending on how you measure) has to be used by the file system to figure out exactly where all of your files are being stored on the card.
I don't know if you ever had to use a card catalog system in a library, but think of it this way.
Let's say you build a library capable of holding a thousand books. However, you're not going to arrange the books according to author's names, titles, or the Dewey Decimal System. You're just going to stick them on shelves in whatever order you get them in.
Whenever you need to find a particular book, you're going to need some way of figuring out exactly where it is in the library. So you'd need a card catalog of sorts. This card catalog is going to take up some of the room in your library, meaning you won't be able to store EXACTLY 1000 books anymore.
Okay, it might not be the best analogy in the world, but it's late here and I hope it gets the point across.
From wikipedia: "A general rule of thumb to quickly convert the manufacturer's hard disk capacity to the standard Microsoft Windows formatted capacity is 0.93*capacity of HDD from manufacturer for HDDs less than a terabyte."
So out of that 7.8GB of space, you're only going to be able to use about 7.3GB of it (7.8 * 0.93).