HDDRIVER and HDDRUTIL support the modern GPT (GUID Partition Table) partition scheme, which is the standard on any PC or Mac. This scheme does not only guarantee high compatibility when exchanging data with other platforms, it also provides increased data security in general.
After receiving some feedback from users who have switched from MBR to GPT, I would like to point out how to profit from some of the advantages the GPT scheme offers. Note that on the Atari currently only HDDRIVER and HDDRUTIL support the GPT partition scheme.
With the old MBR (Master Boot Record) scheme, vital partition data are only stored on a drive once, namely on the first sector (root sector) of a drive. When there are more than 4 partitions, partition data are also stored on other sectors, which are distributed across the drive. When the root sector or any other sector with partition data is corrupted, you cannot anymore access all or at least some partitions. Tools like DISKUS (German only) help with repairing the damage, but they require expert knowledge. Regarding data security you are better off with a GPT than an MBR partition scheme. The GPT scheme stores the complete partition table twice: At the beginning and at the end of a drive. There are checksums that ensure the integrity of these data.
With a GPT, even when the root sector or other partition information is corrupted, all partition data can easily be recovered. In HDDRUTIL, simply select "Repair Partitions". HDDRUTIL will check the available GPT data, and in the case of a corrupted primary partition table or a corrupted root sector will offer to restore all data based on the GPT backup table. HDDRUTIL can also restore the partition data for other platforms and vice versa. This is possible because the GPT scheme is platform-independent.
After repairing the partition table of your boot drive, you have to re-install HDDRIVER. HDDRUTIL only repairs the GPT, but it does not restore the boot code needed by TOS.
When cloning a drive to a larger drive, e.g. by Drag&Drop with HDDRUTIL, the GPT backup on the target drive will naturally not be located at the end of this drive. Also in this case, recovering the GPT data with HDDRUTIL is a solution. This time "Repair Partitions" will notice that it is the backup table and not the primary table that is corrupted, and it will offer to restore it.