Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
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Accessing Media Cache after initalizing it

September 19th, 2019, 7:42

Hi everyone,

I'm learning more and more about Rosewoods and similar drives with large Media Cache contents (and large MC problems). I've now worked on several drives where after making a backup of sysfile 348 and initializing the MCMT through terminal, I get full and quick data access. However, as you will know, access is not complete since I'm ignoring what's inside the Media Cache (most recent files). To fix this, I read the new 348 sysfile from the disk, and import the extents from the original one. However, when I do this, the disk again loses it's ready status when accessing certain sectors from these extents.

I speculate that the reason for this is that the actual extents list is corrupted, maybe by linking a node to a previous one and creating a loop that the drive gets stuck in. I was thinking of maybe analyzing the list but since I don't have much reversing experience, I wanted the opinion of some experts in this forum first. Also if you have a different opinion about why this happens or even some knowledge, any feedback is greatly appreciated!

Anyway, thank you everybody!

Re: Accessing Media Cache after initalizing it

September 24th, 2019, 3:44

Attatching a terminal log so maybe this post gets a little more visibility. I sanitized some of the white space.

Code:
Boot 0x80M
Tech Unlock Handshake: 0x7B7B993E
Reply:

Rst 0x80M
Srv DETCR init 0x0000

(P) SATA Reset

RAW OFF
PASS

(DOS Table) Worst Count: 00000000 At SU: FFFFFFFF NT: 00000000 OT: 00000000
MSP213
(MC POR Duration): 0000000039

Intel 6G->3G
Send Status: COMRESET seen
CSpd= 3Gbps

DSC

PrgF
PrgF

***this is where I access one of the sectors in the extents map***
LED:0x000000BD FAddr:0x00009E23
LED:0x000000BD FAddr:0x00009E23
LED:0x000000BD FAddr:0x00009E23


As I see it, the LED error is related to Media Cache, however I haven't found any reference to that specific FAddr online. Google literally returns 0 results

Also just to add some more info
the drive is a Rosewood_8C,
model number ST1000LM035,
PN 1RK172,
FW SDM1

Re: Accessing Media Cache after initalizing it

September 25th, 2019, 16:41

az-reth wrote:As I see it, the LED error is related to Media Cache, however I haven't found any reference to that specific FAddr online. Google literally returns 0 results

This error means that MCMT or MC is corrupted

Re: Accessing Media Cache after initalizing it

September 26th, 2019, 3:39

Doomer wrote:This error means that MCMT or MC is corrupted

Hi Doomer, thank you for your reply, but did you read the original post? I already know it's media cache related. I want to know if the issue is in some part of the header that Acelab hasn't decoded yet, or if it's media damage, or if it's the actual list of extents that's corrupt. My guess is the latter, and I would like to hear if anyone has played around with trying to fix it.

Re: Accessing Media Cache after initalizing it

September 26th, 2019, 11:47

az-reth wrote: I want to know if the issue is in some part of the header that Acelab hasn't decoded yet, or if it's media damage, or if it's the actual list of extents that's corrupt.

I think I already answered that didn't I?
Let me do it again - It is corrupted
az-reth wrote:
I would like to hear if anyone has played around with trying to fix it.

I don't know if anybody did it and I personally don't see a point to do it.
This particular error is quite rare

Re: Accessing Media Cache after initalizing it

September 27th, 2019, 5:47

Thank you for answering the question. I apologize for being rude.

Still, I think something could be gained from analyzing the list of extents. But if the error is rare as you say, I'll keep it on the backburner for now (like so many other things)
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