Why did mounting /media/MMMCSD work?

Question

I am novice Ubuntu user. I've struggled mounting my SD card on my Ubuntu 11.04. However, I've googled the issue and now I'm able to mount the card. But, I don't know what difference the command made that enabled the SD card to mount and usable? Please help!!

Here is the command I've used to change the settings.

sudo mkdir /media/MMCSD
sudo nano /etc/fstab

then deleted the line starting with /dev/sdb1

then replaced it with the command below

/dev/hdb1 /media/MMCSD vfat auto,user,sync,exec,uid=1000,gid=1000,umask=007 0 0 

This did the magic. Please explain.

Answer 1

Which bit don't you understand?

1. sudo mkdir /media/MMCSD created a directory for you to mount the SD card to. Mounts require a "mount point", this is yours.

2. sudo nano /etc/fstab this edits /etc/fstab as root.

3. /dev/hdb1 /media/MMCSD vfat auto,user,sync,exec,uid=1000,gid=1000,umask=007 0 0 is the mount command. When the system boots, it looks for the device /dev/hdb1 and mounts it at your new mount point. It sets the filesystem to vfat (a fairly typical filesystem for a SD as well as setting a number of fairly default options to allow you to use the drive from your user account.

Answer 2

On top of Oli's excellent answer:

fstab stands for file system table. It is a configuration file that tells the operating system what disk partition the Os needs to mount, as well as the mount point in your file tree. You can also mount/unmount paritions dynamically (see man mount).

The line you added to the file tells the the OS to mount the partition /dev/hdb1 at the mount point /media/MMCSD (your first step made sure the directory existed). The other options are fairly default, as mentioned.