India - Data Recovery

Stellar is a reliable name for all computer data recovery services in India. Stellar has offices spread across the country which cater its expert data recovery service to numerous corporate, institutes, government agencies, and individual customers. Get the best hard drive, laptop, RAID, server, email, database, and file data recovery services at Stellar at affordable price.

DATA RECOVERY SOFTWARE

SQL Database Recovery Software

Stellar Phoenix SQL Database Recovery v2.1, an MS SQL Server repair utility, performs data recovery from all logically crashed MS SQL database files and restores database components at user-specified location. The recovery software can restore almost all SQL database components like, tables, reports, views, and forms.

DB2 Database Recovery Software

Stellar Phoenix DB2 Recovery v1.0 is a database repair application to repair IBM DB2 (UDB) v8 database after any logical damage. The recovery software incorporates high-end scanning procedures to recover almost all DB2 database objects, including schemas, containers, tables, buffer pools, and triggers. The objects can be previewed before restoration.

Access Recovery Software

Stellar Phoenix Access Recovery repairs MDB and ACCDB files and restores them to default or new location. Compatible with Access 2007, 2003, 2002 (XP), and 2000, the database repair software performs repair without changing the original database file. The recovery software is built with intuitive user-interface and can be easy-to-operate.

Oracle Database Recovery

Stellar Phoenix Oracle Recovery v1.0 performs repair of Oracle 9i database in just few mouse clicks. The Oracle data recovery application recovers almost all database objects, like tablespaces, cluster tables, synonyms, indexes, views, tables, and sequences. The software provides a preview of all these database objects before restoration.

Exchange Database Recovery

Stellar Phoenix Mailbox Exchange Recovery v3.0 is an Exchange Server data recovery tool that repairs logically crashed .edb files. Compatible with Exchange Server 5.5, 2000, 2003, and 2007, the tool performs EDB recovery in just three simple steps. The tool also recovers deleted mailboxes and saves them at user-specified location.

DBF Recovery

Stellar Phoenix DBF Recovery v1.0 repairs logically damaged dBase III, dBase IV, dBase V, MS Visual FoxPro 6.0, MS Visual FoxPro 7.0, MS Visual FoxPro 8.0, MS Visual FoxPro 9.0. The DBF data recovery utility restores almost all DBF file components, like table name, column name, primary keys, and column data type.

US - Data Recovery

US - Data Recovery

Stellar Data Recovery Services Inc., offers lab data recovery services to corporate as well as individuals. Stellar has over 16 years of data recovery experience and has expertise in RAID data recovery, SSD data recovery, etc. Stellar engineers can recover data from crashed hard drive, physically damaged drive due to water, fire, accidentally dropping apart from various other data loss situations.

Recovering overwritten data

When data have been physically overwritten on a hard disk it is generally assumed that the previous data are no longer possible to recover. In 1996, Peter Gutmann, a respected computer scientist^[, presented a paper that suggested overwritten data could be recovered through the use of Scanning transmission electron microscopy. In 2001, he presented another paper on a similar topic. Substantial criticism has followed, primarily dealing with the lack of any concrete examples of significant amounts of overwritten data being recovered.^[10][11] To guard against this type of data recovery, he and Colin Plumb designed the Gutmann method, which is used by several disk scrubbing software packages.
Although Gutmann's theory may be correct, there's no practical evidence that overwritten data can be recovered. Moreover, there are good reasons to think that it cannot.

Data carving

Data Carving is a data recovery technique that allows for data with no file system allocation information to be extracted by identifying sectors and clusters belonging to the file. Data Carving usually searches through raw sectors looking for specific desired file signatures. The fact that there is no allocation information means that the investigator must specify a block size of data to carve out upon finding a matching file signature, or the carving software must infer it from other information on the media. There is a requirement that the beginning of the file still be present and that there is (depending on how common the file signature is) a risk of many false hits. Data carving, also known as file carving, has traditionally required that the files recovered be located in sequential sectors (rather than fragmented) as there is no allocation information to point to fragmented file portions.Carving tends to be a time and resource intensive operation.Recent developments in file carving algorithms have led to tools that can recover files that are fragmented into multiple pieces.

Consistency checking

The first, consistency checking, involves scanning the logical structure of the disk and checking to make sure that it is consistent with its specification. For instance, in most file systems, a directory must have at least two entries: a dot (.) entry that points to itself, and a dot-dot (..) entry that points to its parent. A file system repair program can read each directory and make sure that these entries exist and point to the correct directories. If they do not, an error message can be printed and the problem corrected. Both chkdsk and fsck work in this fashion. This strategy suffers from two major problems. First, if the file system is sufficiently damaged, the consistency check can fail completely. In this case, the repair program may crash trying to deal with the mangled input, or it may not recognize the drive as having a valid file system at all. The second issue that arises is the disregard for data files. If chkdsk finds a data file to be out of place or unexplainable, it may delete the file without asking. This is done so that the operating system may run smoother, but the files deleted are often important user files which cannot be replaced. Similar issues arise when using system restore disks (often provided with proprietary systems like Dell and Compaq), which restore the operating system by removing the previous installation. This problem can often be avoided by installing the operating system on a separate partition from your user data.

Recovery techniques

Two common techniques used to recover data from logical damage are consistency checking and data carving. While most logical damage can be either repaired or worked around using these two techniques, data recovery software can never guarantee that no data loss will occur. For instance, in the FAT file system, when two files claim to share the same allocation unit ("cross-linked"), data loss for one of the files is essentially guaranteed.

Preventing logical damage

 The increased use of journaling file systems, such as NTFS 5.0, ext3, and XFS, is likely to reduce the incidence of logical damage. These file systems can always be "rolled back" to a consistent state, which means that the only data likely to be lost is what was in the drive's cache at the time of the system failure. However, regular system maintenance should still include the use of a consistency checker. This can protect both against bugs in the file system software and latent incompatibilities in the design of the storage hardware. One such incompatibility is the result of the disk controller reporting that file system structures have been saved to the disk when it has not actually occurred. This can often occur if the drive stores data in its write cache, then claims it has been written to the disk. If power is lost, and this data contains file system structures, the file system may be left in an inconsistent state such that the journal itself is damaged or incomplete. One solution to this problem is to use hardware that does not report data as written until it actually is written. Another is using disk controllers equipped with a battery backup so that the waiting data can be written when power is restored. Finally, the entire system can be equipped with a battery backup that may make it possible to keep the system on in such situations, or at least to give enough time to shut down properly.

Recovering data after logical damage

Logical damage is primarily caused by power outages that prevent file system structures from being completely written to the storage medium, but problems with hardware (especially RAID controllers) and drivers, as well as system crashes, can have the same effect. The result is that the file system is left in an inconsistent state. This can cause a variety of problems, such as strange behavior (e.g., infinitely recursing directories, drives reporting negative amounts of free space), system crashes, or an actual loss of data. Various programs exist to correct these inconsistencies, and most operating systems come with at least a rudimentary repair tool for their native file systems. Linux, for instance, comes with the fsck utility, Mac OS XDisk Utility and Microsoft Windows provides chkdsk. Third-party utilities such as The Coroners ToolkitThe Sleuth Kit are also available. Even deleted data is also considered to be logically damaged drive for example due to virus attack, if you format the drive or accidental deletion. has and

Some kinds of logical damage can be mistakenly attributed to physical damage. For instance, when a hard drive's read/write head begins to click, most end-users will associate this with internal physical damage. This is not always the case, however. Sometimes, hard drives can click simply when the drive is not getting enough power - which often occurs on USB-powered drives. Another possibility is that the firmware of the drive or its controller needs to be rebuilt in order to make the data accessible again.

Disk imaging

The extracted raw image can be used to reconstruct usable data after any logical damage has been repaired. Once that is complete, the files may be in usable form although recovery is often incomplete.
Open source tools such as DCFLdd or DOS tools such as HDClone can usually recover data from all but the physically-damaged sectors. Studies^[1][2] have shown that DCFLdd v1.3.4-1 installed on a Linux 2.4 kernel system produces extra "bad sectors" when executed with certain parameters^[3], resulting in the loss of information that is actually available. These studies state that when installed on a FreeBSD kernel system, only the bad sectors are lost. DC3dd, a tool that has superseded DCFLdd, and ddrescue resolve this issue by accessing the hardware directly^[3]. Another tool that can correctly image damaged media is ILook IXImager.
Typically, hard disk drive data recovery imaging has the following abilities^[4]: (1) communicating with the hard drive by bypassing the BIOS and operating system which are very limited in their abilities to deal with drives that have "bad sectors" or take a long time to read. (2) reading data from “bad sectors” rather than skipping them (by using various read commands and ECC to recreate damaged data). (3) handling issues caused by unstable drives, such as resetting/repowering the drive when it stops responding or skipping sectors that take too long to read (read instability can be caused by minute mechanical wear and other issues). and (4) preconfiguring drives by disabling certain features, such as SMART and G-List remapping, to minimize imaging time and the possibility of further drive degradation.

Hardware repair

Vehiclepicsall.blogspot.comExamples of physical recovery procedures are: removing a damaged PCB (printed circuit board) and replacing it with a matching PCB from a healthy drive, performing a live PCB swap (in which the System Area of the HDD is damaged on the target drive which is then instead read from the donor drive, the PCB then disconnected while still under power and transferred to the target drive), read/write head assembly with matching parts from a healthy drive, removing the hard disk platters from the original damaged drive and installing them into a healthy drive, and often a combination of all of these procedures. Some data recovery companies have procedures that are highly technical in nature and are not recommended for an untrained individual. See companies such as Ontrack, SalvageData and DriveSavers. Neither of them will void the manufacturer's warranty.

Recovery techniques

Recovering data from physically-damaged hardware can involve multiple techniques. Some damage can be repaired by replacing parts in the hard disk. This alone may make the disk usable, but there may still be logical damage. A specialized disk-imaging procedure is used to recover every readable bit from the surface. Once this image is acquired and saved on a reliable medium, the image can be safely analysed for logical damage and will possibly allow for much of the original file system to be reconstructed.

Recovering data after physical damage

A wide variety of failures can cause physical damage to storage media. CD-ROMs can have their metallic substrate or dye layer scratched off; hard disks can suffer any of several mechanical failures, such as head crashes and failed motors; tapes can simply break. Physical damage always causes at least some data loss, and in many cases the logical structures of the file system are damaged as well. Any logical damage must be dealt with before files can be salvaged from the failed media.
Most physical damage cannot be repaired by end users. For example, opening a hard disk in a normal environment can allow airborne dust to settle on the platter and become caught between the platter and the read/write head, causing new head crashes that further damage the platter and thus compromise the recovery process. Furthermore, end users generally do not have the hardware or technical expertise required to make these repairs. Consequently, costly data recovery companies are often employed to salvage important data.

DATA RECOVERY

Data recovery is the process of salvaging data from damaged, failed, corrupted, or inaccessible secondary storage media when it cannot be accessed normally. Often the data are being salvaged from storage media such as hard disk drives, storage tapes, CDs, DVDs, RAID, and other electronics. Recovery may be required due to physical damage to the storage device or logical damage to the file system that prevents it from being mounted by the host operating system.

The most common "data recovery" scenario involves an operating system (OS) failure (typically on a single-disk, single-partition, single-OS system), in which case the goal is simply to copy all wanted files to another disk. This can be easily accomplished with a Live CD, most of which provide a means to mount the system drive and backup disks or removable media, and to move the files from the system disk to the backup media with a file manager or optical disc authoring software. Such cases can often be mitigated by disk partitioning and consistently storing valuable data files (or copies of them) on a different partition from the replaceable OS system files.

Another scenario involves a disk-level failure, such as a compromised file system or disk partition or a hard disk failure. In any of these cases, the data cannot be easily read. Depending on the situation, solutions involve repairing the file system, partition table or master boot record, or hard disk recovery techniques ranging from software-based recovery of corrupted data to hardware replacement on a physically damaged disk. If hard disk recovery is necessary, the disk itself has typically failed permanently, and the focus is rather on a one-time recovery, salvaging whatever data can be read.

In a third scenario, files have been "deleted" from a storage medium. Typically, deleted files are not erased immediately; instead, references to them in the directory structure are removed, and the space they occupy is made available for later overwriting. In the meantime, the original file may be restored.

Although there is some confusion as to the term, the term "data recovery" may be used to refer to such cases in the context of forensic purposes or spying.