Download link of video tutorial: http://us.mrtlab.com/video/sgthidbadsebyhed.rar
When bad tracks appear regularly in hard drive, there is very likely to be radical scratch on platter or problem of head. For radial scratch on platter, we can shield bad tracks by zone to shield the scratched zone. For hard drive with head problem, we can shield bad tracks by shielding head so as to disable the area controlled by damaged head. In this way, other good heads can be used. The operation process of these two features is similar. So here we illustrate them in the same tutorial.
First, let’s see how to shield bad tracks by zone. Here is a disk for demonstration.
Let’s scan to see the disk status. This is a Seagate 7200.12 disk. Since there is a damaged head, the range of bad tracks is wide, so we need to check “skip when there are bad tracks” to save time. Record the location of bad tracks – LBA 26624. The first group of bad tracks should be located in the same zone. Now the second group of bad tracks is encountered. Let’s try to shield the zone where the bad tracks locate. First, we should determine which zone it is. Select several LBAs to test. LBA: 26624,331008,410880. Then we check the LBA information with address translator.
26624: head 0, zone 0
331 008: head 0, zone 0
410,880: head 1, zone 10 (hex)
Since we have found the head and zone where the bad tracks locate, let’s shield it.
Step 2: Shield zone of specified head.
In order to avoid being affected by G-List, let’s clear G-List first. Open the menu Tools -> Disk repair tool -> Shield bad tracks by zone
This list will show all the sub-zones of each head. Please note that the zones listed are sub-zones, not major zones.
Let’s look at major zones first. Input command “x” in 2 Level. The selected part is major zones, i.e. zone 00 – zone 10
Actually each major zone is divided into many sub-zones. Head switching is done according to sub-zones, not major zones. For example, ZONE 00, with starting track and ending track being 000000 and 0003D3, can be divided into multiple sub-zones. Let’s look at the starting track and ending track of each sub-zone. Shield zone -> Advanced tools, there lists head number and major zones of each head. Decimal 0 -16 correspond with hex Zone 00 – Zone 10. Check the major zone 00 of head 0, the program will automatically check corresponding sub-zones. We can see there are many sub-zones included in Zone 0.
We can shield each sub-zone individually, or shield the entire major zone.
Now we check the major zone to be shielded.
Select head 0, major zone 0, and head 1, major zone 10 (=decimal 16), the program select the corresponding sub-zones automatically.
Write to disk in ATA mode.
Step 3: If there are many zones to be shielded, we need to reduce the capacity first.
This step is optional. While sometimes if you don’t reduce the capacity before recalculating translator, it can fail or succeed with no actual effectiveness in recalculating translator. If many zones are shielded, the capacity of hard drive will surely be smaller. So we need to modify the capacity of hard drive first. Note: the reduced capacity should equal the total sector length of shielded zones. Most important of all, we should modify the capacity in RAP. The capacity in CAP and modules has little effect on shielding zone and head. Menu of modifying capacity in RAP: Tools -> SA Tools -> Modify RAP. Here we also modify the capacity in CAP.
Step 4: Recalculate translator
Clear G-List with command “i4” to avoid affected by data of G-List. Then recalculate translator with command “m0,6,3 ,,,,, 22”.
This step usually takes a long time. Here we pause videotaping to save time.
We can see that recalculating translator failed. This fault can usually be encountered by users. There are several possible causes. The first possible cause is capacity not modified. The second is that there are repeated entries (conflicting entries) in P-List. For this, we will illustrate the solution in the following part “shield bad tracks by head”. Here we should make sure that Step 3 – Modify HDD capacity is completed. We can see that after modifying capacity in RAP, recalculating translator succeeded.
Step 5: Erase sectors
There are several optional schemes for erasing sectors, the first is to format the disk with command “m0,8,3 ,,,,, 22”, the second is scan in “Write” mode, the third way is to use the erasing function of security subsystem. Here we erase the sectors by scanning in “Write” mode. To save time, we will only erase part of sectors. When users finish erasing the whole disk, they can do normal scan. Users can see the zones with bad tracks have been shielded.
Above is the operation process of shielding bad tracks by zone.
Then let’s demonstrate how to shield bad tracks by head. Here we user a Seagate 7200.11 hard drive.
The operation process of shielding bad tracks by head:
Step 1: Scan the hard drive to determine which head needs to be shielded.
We see this hard drive showing typical symptom of weak head. Selected a LBA to test which head is weak.
We can see from the tested LBA that head 0 is weak. It needs to be shielded.
Step 2: Shield specified head
Clear G-List. Then go to ATA mode, open the menu Tools -> Disk repair tool -> Shield bad tracks by head
Select the head to be shielded, click “OK”. Then area controlled by the head is added to defect list.
Step 3: Recalculate translator
Clear G-List with command “i4”, and input the command “m0,6,3 ,,,,, 22”.
It takes a long time to be completed.
This step is the most prone to problems. Now let’s consider that if there is error in this step, what should we do? We can see there is LED error when recalculating translator. In this case, recalculating translator failed. As a result, shielding bad tracks by head will not succeed.
We can try to solve the problem with the following three ways:
1. Update firmware
Sometimes we need to update firmware to shield head successfully. Download firmware package provided by MRT, and write the compatible firmware of newest version to disk.
This hard drive is 7200.11. We should use SD1A. If it is 7200.12, we should use CC49.
After updating firmware, repeat Step 2 and Step 3.
If it still fails, try the second method.
2. Delete the entries in P-List which belong to the shielded head.
Recalculating translator failed may be caused by repeated entries (conflicting entries) in P-List. We need to delete them. Take shielding head 0 as an example, we should delete the entries in P-List which belong to head 0. Then repeat Step 2 and Step 3.
Let’s restore translator first and then delete entries of P-List. Write edited P-List to disk.
Repeat step 2 and step 3.
Generally, recalculating translator will succeed (especially for 7200.12 disks).
But failure can still occur in some hard drives. Then try the third way.
3. Reduce capacity in RAP.
Minus the capacity of area which belongs to shielded head with RAP capacity. As a head is shielded, the capacity will surely be decreased.
Modify the capacity with the menu “Edit RAP “. Remember to power off the disk and then power on so that the modification can take effect.
Repeat step 2 and step3.
With the three methods above, we can shield head successfully.
Recalculating translator can take a lot of time.
Generally speaking, for 7200.11 hard drives, it usually takes at least 5 hours to recalculate translator with command “m,0,6,3,,,,,22”. While for 7200.12 hard drives, the speed is much faster as the algorithm of recalculating translator is optimized in 7200.11 hard drives. Now we pause videotaping and continue when recalculating translator is completed.
Recalculating translator completed. Let’s go to the next step.
Step 4: Erase sectors.
There are several optional schemes. The first is to format the disk with command “m0,8,3 ,,,,, 22”. The second is to scan in “Write” mode. The third is to use the erasing function of security subsystem. Here we scan in “Write” mode to erase the sectors. To save time, we will only erase part of the sectors. Users should do normal scan after completing erasing the whole disk. Then we can see the area controlled by damaged head has been shielded.
Above is the operation process of shielding bad tracks by head.
Next, we connect the 7200.12 disk again to demonstrate the whole process of shielding bad tracks by head.
We can see that the process succeeded even with there being repeated entries in P-List. If it fails, we can delete the repeated entries in P-List and try again.
Above are the operation processes of shielding bad tracks by head and shielding bad tracks by zone. Thanks for watching.