..:: HDDLAB ::..


Recuperação de desastres ocorridos com mídias de dados.

Firmware Problems on Seagate SCSI Hard Disk Drives

        HDDLAB is one of a few Hard disk Drive Laboratories in World that can perform Data Recovery in Seagate SCSI hard disk with firmware problems

SCSI HARD DISK
        Since 2004 we start to study some specific problems that we realize that they are very comun in hard disks SCSI and with the cooperation of others WORLDWILDE DATA RECOVERY companies we develop a combination of hardware and software that let us perform repairs in damage SCSI disks.
        The experience that we had in our research in IDE/ATA and SATA disks gave us the chance to discover how to start our research in SCSI Seagate disks, we first saw that the symptoms in this disk was dependent upon the SCSI or RAID controller in use, but usualy we also saw that the disks are still recognised, with one factor very interesting the disk allways report that its has 0 MB. Sometimes in some RAID controllers the disk can show that is failed. SCSI disks has one thing that is commum to all them, and this is the SENSE code, this codes you can see when the computer start and the SCSI apdater is showing the SCSI disk, has a line with some info about the disk, and is commun in our case that the sense code is 03h also in this line is possible to read “medium error”. We can say that this is a power failure in ( or during ) data write. We know that the main problem is that the tables where is stored the factory zone become corrupt and after this they are modified and the Error Correction Codes (ECC) are written after the data write is complete. When the ECC fails the factory zone become inaccessible and they develop a soft error that is also called “bad block”.Since this facts, next time the drive turn on after the failure, the tables are unable to be read correctly and the drive will not initialise correctly and generates an error.

        We have worked in the problem and we discover where these tables are stored in the factory zone of the hard disk and with a combination of hardware and software we are able to access them and repair the ECC codes to bring the drive back online, at least long enough for data recovery purposes.

        We also know that there is only a few companies in the world that are able to recover drives with this problem. Our combination of harware and software let us do complex tests, repair and recover the user data from damaged SCSI hard disks. We can work with one disk or in any RAID systems from 2 up to 15 SCSI in a RAID SYSTEM.

        Defintion of RAID: Redundant Array of Inexpensive Drives is a method of increasing data storage by means of using groups or 'arrays' of small (inexpensive) hard drives creating a single large drive. There are several RAID configurations and each has its advantages and disadvantages.

        RAID 0 (Striping Without Parity) consists of two or more drives with the data striped across the entire array. There is no fault tolerance, so a failure within a RAID 0 array will result with inaccessible data. RAID 1 (Mirroring and Duplexing) - Consists of at least two drives. the data on the second drive is identical to the data on the first drive. If one drive fails, then there is a complete copy on the other drive.
RAID 5 is the most common RAID level and requires at least three drives. Data is stored in stripes with a distributed parity stripe across the drives. This removes the bottleneck found in RAID 3 and 4 and is the best option when considering RAID arrays with parity.

        This RAIDs types are the most comun, but we also can work in all others RAID systems, also when they are composed by SATA disks or even IDE disks.
         When we are working with SCSI disk we can run tests and we can do service operations independently on each of them and we also can perform tests and operations in the system.
        We can provide tests to see the performance of various operations in a SCSI hard disk and this tests will allow us to performe a complete check-up of all their functionality in accordance with the INTERNATION SCSI HARD DISKs specifications.

The list of tests and procedures that we can perform in SCSI disks:

Running of elementary tests (readiness check, recalibration, self-diagnostics, drive ID reading, spindle stop/start).
Surface verification.
Read, write, and seek tests.
Complex HDD test including all of the above.
Reading and viewing of PLIST and GLIST defect tables.
Relocation of defects.
Low-level HDD format.
Launch of short HDD self-test.
HDD image creation.

We are able to do clones on SCSI disks that can be performed from a single drive to several ones simultaneously. The clone are useful in cases when source SCSI hard disk has damaged sectors and we have to recover its data, but hanging or malfunctioning drive does not permit the operation normaly. Our System can save any part of HDD surface to a file on another HDD and then record the data to a selected hard disk. The feature may be applied for hard disk duplication or data recovery.

Currently we have specialized utilities for:

IBM-HGST SCSI DISKS
MAXTOR SCSI DISKS
SEAGATE SCSI DISKS
QUANTUM SCSI DISKS

We can perform tests in thouse drives in factory mode, we can save and procede with the restoration of their firmware data. In case of error detection our system uses an additional list of Specific Vendor Error Codes. The list of SCSI erros are not only based in the Vendor Error Codes they also have the SENSE ERRORs CODE that in many cases allows very precise definition of its background as well as possible methods of hard disk repair for procede with the data recovery.