How many type of disk in VM ?( falt, thin .etc)

There are 5 types of Disk in ESX.
1. Zeroedthick
2. Eagerzeroedthick
3. Thin
4. Thick
5. RDM
An other type of disk is used in workstation which is 2GB sparse disk.
Zeroedthick (default) .
Space required for the virtual disk is allocated during creation. Any data remaining on the physical device is not erased during creation, but will be zeroed out at a later time during virtual machine read and write operations.
Eagerzeroedthick
Space required for the virtual disk is allocated at creation time. Unlike with the zeroedthick format, the data remaining on the physical device is zeroed out during creation. Disks in this format might take much longer to create than other types of disks.
Thick
Space required for the virtual disk is allocated during creation. This type
of formatting doesn't zero out any old data that might be present on this allocated space.
Thin
Thin-provisioned virtual disk. Unlike with the thick format, space required
for the virtual disk is not allocated during creation, but is supplied, zeroed out, on demand at a later time.
RDM
Direct access to storage LUN. Other disks are called as Virtual disk and RDM is called as Physical disk. Unlike others the information is not stored on datastore or in a File, but stored on the LUN directly. This is presented using NPIV to the VM's