Data Recovery Blog

HJ-Split (Freeware file splitter for a variety of platforms)
Why split files? Think of a file of 20 Mb, and try to send this to a friend. Using email this does not succeed, it is simply too large, and how to put it onto a floppy? HJSplit will enable you to split the large file into smaller chunks, which can be much more easily sent and stored. Later on these chunks can be re-joined using HJSplit itself or HJJoin.

HJSplit is available for a large number of operating systems:Windows 95/98/NT/2000/XP, Linux, Java, OS/2, Windows 3.x, MS DOS, Amiga. For the MAC there is a compatible file joiner available.

Freebyte ZIP
A powerful freeware ZIP program with full Windows user-interface. It can zip and unzip files, create new zip files, directly view and sort zip file contents, make self-extracting archives, password protect and encrypt files, etc. etc. Runs on windows 95, 98, ME, 2000, NT and XP.

StuffIt
Mac file expander (program to open compressed files) for the MAC platform. Support for various file formats, like BinHex, MacBinary, zip, gzip, uu, tar. Lite version is freeware.

Hard Disk Repair

Free Disk Catalogue Programs

DATARECOVERYUNION.COM16 years ago12 years ago11 mins

Catfish
Small, free and automatic disk inventory program for Windows. For people who can’t remember what they put on their ZIP disks, floppies or CD-roms! We use it at Freebyte.

Cathy
A similar program (not only in name) to Catfish. Has searching capabilities based on file name, date and size. Customizable date format. Found files can be opened directly, if they are present. Only contains a small single executable file, meaning that no installation is needed. Runs on Windows.

Data Storage

RAID Array & Server Glossary of Computer Terms (Letter F)

DATARECOVERYUNION.COM16 years ago12 years ago53 mins

Failback
Restoring a failed system component’s share of a load to a replacement component.

Failover
A mode of operation for failure tolerant systems in which a component has failed and a redundant component has assumed its functions.

Failover Port
A fibre channel port capable of assuming I/O requests for another, failed port on the loop. During normal operation, a failover port may be active or inactive. Failover ports assume the same loop ID and, optionally, the same node from the failed port.

Failure
A detectable physical change in hardware, requiring replacement of the component.

Fault Tolerance, Failure Tolerance
The ability of a system to continue to perform its function even when one of its components has failed. A fault tolerant system requires redundancy in disk drives, power supplies, adapters, controllers, and cabling. Mylex RAID controllers offer high levels of fault tolerance.

Failed-drive mode
A mode of reduced-performance operation that a disk array is in after a drive failure.

Failover
The automatic replacement of a failed system component with a properly functioning one. Most often used in the context of redundant external array controllers. If one of the controllers fails, failover enables the second controller to take over the failed controller’s I/O load.

Fault tolerance
The ability of a system to continue to perform its functions, even when one or more components have failed

Fibre Channel
Technology for transmitting data between computer devices at a data rate of up to 2 Gbps (two billion bits per second), especially suited for connecting computer servers to shared storage devices and for interconnecting storage controllers and drives.

Fibre Channel is expected to replace the Small System Computer Interface (SCSI) as the transmission interface between servers and clustered storage devices. It is also more flexible: devices can be as far as ten kilometers (about six miles) apart. The longer distance requires optical fiber as the physical medium; however, fibre channels also work using coaxial cable and ordinary telephone twisted pair wires.

Flash ROM
Memory on an adapter containing software that can be reprogrammed without removing it from the board.

Data Storage

RAID Array & Server Glossary of Computer Terms (Letter E)

DATARECOVERYUNION.COM16 years ago12 years ago03 mins

ECC
Error Correcting Code, a method of generating redundant information which can be used to detect and correct errors in stored or transmitted data.

Embedded Storage Controller
An intelligent storage controller that mounts in a host computer’s housing and attaches directly to a host’s memory bus with no intervening I/O adapter or I/O bus.

External RAID Controller
A RAID controller in its own enclosure, rather than incorporated into a PC or server. External RAID controllers are often referred to as a Bridge RAID Controller. Mylex SANArray FL, FF, FFx, and Pro FF2 controllers are external RAID controllers. Compare with Internal RAID Controller.

Exclusive OR (XOR)
A process based on a mathematical algorithm that is used by RAID levels 2, 3, 4, and 5 to compare computer data (binary 0s and 1s) created by a write request or by a read request during a drive failure. The result of the XOR process is parity information that will be stored along with data for real-time recovery in the event of a disk failure.

External array controller
In contrast to bus-based array adapters and microprocessor-based array controllers, external array controllers reside in the external RAID storage enclosure. They connect to the host through a standard SCSI or serial (such as Fibre Channel) host adapter interface. These external controllers are similar to bus-based, microprocessor-based array controllers, in that they include an on-board microprocessor to offload all RAID functions (I/O commands and RAID operations) from the host CPU. They are usually used in midrange and high-end servers, especially in clustering environments.

Data Storage

Seagate Introduces Constellation: All-Star Enterprise Hard Drives

DATARECOVERYUNION.COM16 years ago3 years ago19 mins

The Constellation family includes 2.5-inch nearline hard drive with lowest enterprise power consumption and record-setting 3.5-inch 7200-rpm 2TB hard drive for nearline Tier 2 enterprise applications

Seagate introduced its Constellation™ family ofnew enterprise storage solutions for Tier 2 nearline storage applications. The two new drive models, the 2.5-inch Constellation and the 3.5-inch Constellation ES hard drives, include a combination of features that enable high capacities, increased power efficiency, enterprise-class reliability, and data security. Both drives also include PowerChoice™ from Seagate, which decreases power consumption by up to 54% for record power savings in enterprise environments. John Monroe, a research vice president at Gartner said：

“The need for greater storage capacity will continue to expand in multiple directions and dimensions, but there will be an increasing scrutiny of all storage system purchases, with an eye to decreasing power consumption, footprint, and cost per GB in unprecedented ways, Performance will not be ignored, but a flexible balance of capacity, cost per GB, power and speed will become more crucial in fulfilling end-user storage demands at varied price points.”

Constellation
The Constellation 2.5-inch hard drive is offered in capacities of 160GB and 500GB with both 3 Gbps SATA and new SAS 2.0 interface running at 6Gb/s speeds. As the first SAS 2.0 nearline drive, the Constellation hard drive enables larger external storage topologies, 100% faster data throughput and higher signal strength over greater distances – dramatically increasing storage scalability. The Constellation family will begin shipping this quarter. Praveen Asthana, director of Dell Storage said：

“Dell recognizes that increased capacity and high-reliability are key to enabling further adoption of small form factor storage within the enterprise. With new capacities, small form factor drives afford customers performance and power gains within the same rack space, As an industry-leader in storage, Dell is pleased to partner with Seagate and be one of the first companies to offer the Constellation family of drives to our customers.”

Constellation ES
The 3.5-inch Constellation ES hard drive will be available in 500GB, 1TB and 2TB capacities, and with an enterprise-class SAS interface as well as a SATA version, and provides best-in-class capacity and performance. As the world’s only 7200-rpm 3.5-inch hard drive providing up to 2TB of storage, the record-setting capacity of Constellation ES hard drives are ideal for 3.5-inch based external storage architectures. With Constellation ES hard drives, customers don’t have to sacrifice performance in order to gain the highest capacities. The Constellation ES hard drive will ship in calendar Q3.

Todd Gresham, executive vice president and general manager of the Networked Storage Solutions Division for Xyratex said:

“Xyratex continues to work closely with Seagate to advance storage system innovation to meet both the performance and capacity-based market requirements, the new Constellation family of products complements Xyratex’s philosophy of delivering cost-effective enterprise-class, energy efficient storage solutions that help provide our customers the long-term investment protection they demand.”

With Seagate’s innovative PowerChoice technology, both Constellation hard drive models deliver the highest power-reduction savings ever offered in an enterprise-class HDD, and provide flexible, user-manageable options to deliver power savings without sacrificing performance, data integrity, or reliability. In addition, the Constellation family of drives are backed with field-proven, enterprise-grade reliability and rated at a full 1.2 million hours MTBF.

Delivering on Seagate’s commitment to add security features throughout its product portfolio, the Constellation family of drives are offered with optional self-encrypting drive (SED) technology and provide government-grade data security through the drive’s life cycle. SED technology makes drive retirement and disposal easy by eliminating the need for the numerous manual processes involved which are often incomplete, complex, expensive, or prone to error. For critical information that must remain secure, and because all systems are eventually retired, whether being relocated, re-purposed, or disposed of, the information on a Constellation SED hard drive remains AES-safe.

Seagate Unified Storage™ architecture delivers long-term business sustainability
Historically, the variety of drive interfaces, form factors and now, security solutions, can add complexity and increase costs for both IT professionals and OEMs. Making the wrong choice today creates storage islands in the data center with no easy path for upgrades – further complicating an already complex environment. The Seagate Unified Storage architecture converges best-of-breed technologies (Serial Attached SCSI, Small Form Factor and Self-Encrypting Drives) into a foundation for powerful yet simple storage that boosts business and operational efficiency while reducing cost and complexity.

The Seagate Unified Storage architecture delivers a storage foundation for companies that are proactively ensuring the long-term sustainability of their business through best-in-class IT practices. Companies will avoid the risk of impacting their own product quality, competitiveness, or profitability when their storage system infrastructure and data center footprint is optimized across power, cooling and performance density. Because the role of small form factor drives are important to the long-term efficiency and sustainability of any data center enterprise, Seagate will be extending this component into all tiers of its Unified Storage architecture in the future.

Sherman Black, senior vice president, Seagate Core Marketing and Strategy said：

“With tightening IT budgets, Seagate is committed to delivering enterprise-class nearline storage solutions that ensure business sustainability by optimizing resources, reducing environment, energy or social impact and satisfying customer requirements without compromising performance, these new Constellation HDDs provide business continuity in the data center by offering the highest capacities, the lowest power, and the latest in enterprise-class data integrity with SAS 2.0 and AES government-grade encryption.”

For more information about the Constellation family of drives, in addition to Seagate’s other enterprise storage solutions, visit www.seagate.com.

Data Storage

RAID Array & Server Glossary of Computer Terms (Letter D)

DATARECOVERYUNION.COM16 years ago12 years ago06 mins

Data Caching
Temporary storage of new write data or high-demand read data in solid state memory in order to accelerate performance. The cached data is later overwritten with newly cached data once it is either written to disk or deemed to be of low demand.

Demand caching
A performance caching technique in which the currently requested data is read in anticipation of another request before its allocated blocks are recycled. Reassignment of the blocks is done on the basis of least recently used (LRU).

Degraded Mode
A RAID mode used when a component drive has failed.

Disk
A non-volatile, randomly addressable, re-writable data storage device, including rotating magnetic and optical disks as well as solid-state disks or other electronic storage elements.

Disk Array
A collection of disks from one or more commonly accessible disk systems. Disk arrays, also known as RAID, allow disk drives to be used together to improve fault tolerance, performance, or both. Disk arrays are commonly used on servers and are becoming more popular on desktops and workstations. See also Array.

Disk Drive
A device for the electronic digital storage of information.

Disk Failure Detection
A RAID controller automatically detects SCSI disk failures. A monitoring process running on the controller checks, among other things, elapsed time on all commands issued to disks. A time-out causes the disk to be “reset” and the command to be retried. If the command times out again, the controller could take the disk “offline.” Mylex DAC960 controllers also monitor SCSI bus parity errors and other potential problems. Any disk with too many errors will also be taken “offline.” See also Offline.

Disk Traveling, Drive Traveling
A process that occurs when the drives are placed in a different order than the original order. Disk traveling can occur whether or not a drive has failed.

Disk System
A storage system capable of supporting only disks.

Drive Groups, Drive Packs
A group of individual disk drives (preferably identical) that are logically tied to each other and are addressed as a single unit. In some cases this may be called a drive “pack” when referring to just the physical devices. All the physical devices in a drive group should have the same size; otherwise, each of the disks in the group will effectively have the capacity of the smallest member. The total size of the drive group will be the size of the smallest disk in the group multiplied by the number of disks in the group. For example, if you have 4 disks of 400MB each and 1 disk of 200MB in a pack, the effective capacity available for use is only 1000MB (5×200), not 1800MB.

Disk/data striping
Spreading data evenly over multiple disks to enhance performance. Sometimes referred to as RAID 0, data striping actually has no redundancy scheme and, therefore, does not provide any fault tolerance (data protection).

Drive
Synonym for disk, hard drive, hard disk, disk drive.

Dual Active
A pair of components, such as storage controllers in a failure tolerant storage system, that share a task or set of tasks when both are functioning normally. When one component of the pair fails, the other takes the entire load. Dual active controllers (also called Active/Active controllers) are connected to the same set of devices and provide a combination of higher I/O performance and greater failure tolerance than a single controller.

Duplexing
Mirroring across two host adapters. Used only with software-based RAID storage systems (usually the embedded network operating system RAID software such as NetWare and Windows NT).

Data Storage

RAID Array & Server Glossary of Computer Terms (Letter C)

DATARECOVERYUNION.COM16 years ago12 years ago33 mins

Cache
A temporary storage area for frequently accessed or recently accessed data. Cache is used to speed up data transfer to and from a disk. See also Caching.

Cache Flush
Refers to an operation where all unwritten blocks in a Write-Back Cache are written to the target disk. This operation is necessary before powering down the system.

Cache Line Size
Represents the size of the data “chunk” that will be read or written at one time, and is set in conjunction with stripe size. Under RAID EzAssistTM, the cache line size (also known as Segment Size) should be based on the stripe size you selected. The default segment size for Mylex RAID controllers is 8K. See also Stripe Size.

Caching
Allows data to be stored in a pre-designated area of a disk or RAM. Caching speeds up the operation of RAID systems, disk drives, computers and servers, or other peripheral devices. See also Cache.

Conservative Cache
An operating mode in which system drives configured with the Write-Back Caching policy are treated as though they were configured for Write-Through operation and the cache is flushed.

Consistency Check
A process that verifies the integrity of redundant data. A consistency check on a RAID 1 or RAID 0+1 configuration (mirroring) checks if the data on drives and their mirrored pair are exactly the same. For RAID Level 3 or RAID Level 5, a consistency check calculates the parity from the data written on the disk and compares it to the written parity. A consistency check from Mylex utilities such as Global Array ManagerTM (GAM) or RAID EzAssistTM give the user the ability to have a discrepancy reported and corrected. See also Parity Check.

Controller
An adapter card, RAID controller, or other module that interprets and controls signals between a host and a peripheral device.

Computer Forensic

Computer Forensics

DATARECOVERYUNION.COM16 years ago12 years ago03 mins

Data lost intentionally or accidentally can be recovered with the help of data recovery experts. Computer forensic is one such type where the cause for data loss is identified.

There are many definitions of computer forensics however generally, computer forensic refers to the detail investigation of the computers to carry out the required tasks. It performs the investigation of the maintained data of the computer to check out what exactly happened to the computer and who is responsible for it. The investigation process starts from the analysis of the ground situation and moves on further to the insides of the computer’s operating system.

Computer forensic is a broader concept which is mainly related to the crimes happening in computer which is against law. Various laws have been imposed to check out the crimes but still they exist and are difficult to find the criminal due to lack of evidence. All these difficulties can be overcome with the help of computer forensics.

The main motto of computer forensic experts is not only to find the criminal but also to find out the evidence and the presentation of the evidence in a manner that leads to legal action of the culprit. The major reasons for criminal activity in computers are:

Unauthorized use of computers mainly stealing a username and password
Accessing the victims computer via the internet
Releasing a malicious computer program that is virus
Harassment and stalking in cyberspace
E-mail Fraud
Theft of company documents.

Computer forensic facilitates the organized and careful detection of computer related crime and abuse cases. The computer forensics expert should have a great deal of knowledge of the data recovery software as well as the hardware and should possess the qualification and knowledge required to carry out the task.

Data Storage

Data Storage Glossary

DATARECOVERYUNION.COM16 years ago12 years ago010 mins

A
1394
The Institute of Electrical and Electronics Engineers (IEEE) designation for an interface developed for easy connection to consumer devices such as video and computer peripherals.

Adapter Card
In order to connect a computer to peripheral devices, an adapter card is often required. The adapter plugs into the computer’s bus, and connects the system’s data path to the peripheral.

Arrays
A group of disk drives that appear to a computer as a single logical unit. In order to use arrays effectively, RAID software and/or hardware is required.

B
Bandwidth
A data transmission rate; the maximum amount of information (bits/second) that can be transmitted along a channel.

Bus
A set of conductors connecting the various functional units in a system.

C
CD-R (Compact Disc-Recordable)
A blank CD that is designed to allow data to be “written” a single time on its surface. Peripheral devices that connect to PCs enable home or office single-time recording of blank CD-Rs.

CD-RW (Compact Disc-Rewritable)
A blank CD that is designed to allow data to be written, erased, and rewritten onto a CD-RW. Rewritable capability makes CDs more versatile by mimicking the usability of floppy disks.

D
Data Caching
Temporary storage of new write data or high-demand read data in solid-state memory in order to accelerate performance. The cached data is later overwritten with newly cached data once it is either written to disk or deemed to be of low demand.

Data Path
Digital information can be transmitted in different sized “paths” within a computer. Generally, the wider the data path, the higher the throughput performance. Today, the most standard data path width is 32-bit, though new products are entering the market with 64-bit paths, providing better I/O performance.

Disk Drive
Computer storage hardware that can read and write information on it.

E
EID
Enhanced Integrated Drive Electronics. A low cost, limited functionality drive interface. Controlled by the ANSI X3T9.2 committee.

Ethernet
A type of networking technology for local area networks.

F
Fault Tolerance
The ability of a system to continue to perform its functions, even when one or more components have failed.

Fibre Channel
A channel/network standard that provides connectivity, distance, and protocol multiplexing.

I
I/O Bus
The I/O bus is where the computer connects to outside peripherals.

I/O Channel
In computer systems, I/O Channel refers to the physical interface that controls the transfer of data between the computer and peripheral devices. With SCSI, each I/O Channel is equivalent to the full functionality of a single SCSI host adapter. For example, a dual-channel SCSI host adapter is equivalent to two single SCSI host adapters.

I/O Subsystem
The combination of technologies that manage the process of moving data into and out of the main computer system. The highest performance I/O subsystems use dedicated processors to minimize the CPU’s need to manage I/O, thereby allowing it to process the information that is moved to it from the I/O subsystem.

M
Mirroring
Also known as RAID 1 or duplexing (when using two host bus adapters). Full redundancy is obtained by duplicating all data from a primary disk on a secondary disk. The overhead of requiring 100% data duplication can get costly when using more than two drives.

Motherboard
The main printed circuit board in a system generally containing the bus, microprocessor, and chips used for controlling any internal peripherals.

Multitasking
The ability for the operating system to perform multiple operations at once. Windows NT Workstation is a multitasking operating system that can perform multiple I/O requests at once. SCSI and a Caching RAID coprocessor take advantage of multitasking.

N
Network Interface Card (NIC)
An adapter installed in a computer to provide a physical connection to a network.

P
Parity
When the data stream is split between several disks with an extra disk providing error protection.

PCI (Personal Computer Inter-connect)
PCI is the most common high-performance bus type. Currently, PCI uses a 32-bit wide data path, but newer PCI products are adopting a 64-bit wide data path for improved performance.

Peripheral
Internal or external devices connected by cable to a system.

R
RAID (Redundant Array of Independent/Inexpensive Disks)
A method of combining multiple disk drives into a single logical storage unit. Multiple levels of RAID provide different features. RAID Level 0 is the fastest type of RAID. It stores data across all the drives, letting users access information from multiple drives simultaneously. RAID Level 1 protects data by mirroring it on multiple drives, so performance is only slightly better than that of a single drive. RAID Level 5 does a combination of the two, providing the best overall balance.

Read-ahead Caching
A performance caching technique in which data is anticipated and read into the cache before it is actually requested.

S
SAN (Storage Area Network)
SANs are an evolving approach to storage, where multiple storage devices are connected to multiple servers for higher capacity, throughput, and reliability. SANs require sophisticated RAID management software and high-performance I/O connectivity.

SCSI (Small Computer System Interface, pronounced “scuzzy”)
SCSI is the preferred industry standard for high-performance I/O interface. Particularly valuable in servers where one system must connect to many high-capacity storage devices without lowering the I/O speed to the slowest device.

S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology)
Drives equipped with this feature report predicted failures based on threshold values determined by the manufacturer. This allows the network manager to replace a drive before it fails.

Storage
Computers store information on a variety of devices, some inside the system, and others external to the computer. Typically, data is written to a particular kind of storage medium using a disk drive. Common media include flexible (floppy disk drive), rigid (hard disk drive), tape, or optical (CD).

Striping
Also known as RAID 0. Two or more drives store and retrieve data in parallel, accelerating performance.

W
Write-back Caching
A performance caching technique in which the completion of a write request is signaled as soon as the data is in cache. Actual writing to the disk occurs at a later time.

Write-through Caching
A caching technique in which the completion of a write request is not signaled until data is safely stored on disk

Data Recovery

Guideline for Diagnostics – Data Recovery

DATARECOVERYUNION.COM16 years ago12 years ago06 mins

This is intended to be a guideline for determining whether a hard drive is failing physically or if the drive is a candidate for software recovery by technicians in the field.

There are many commercial utilities that will allow users or qualified technicians to recover data from a hard drive that is otherwise inaccessible. Commercial utilities work with varying degrees of success. The question to be asked is when is it a good idea to use these utilities versus when is a good idea to send the hard drive to Data Recovery Group?

The first step is to determine if the hard drive is functioning. If the hard drive is functioning properly it should be recognized in the CMOS and you should be able to boot the system from another media source, such as a floppy, CD-ROM, or another hard drive. If there are any BIOS errors when attempting to boot the system the hard drive has malfunctioned and needs to be sent to Data Recovery Group. If during the boot process the system is unable to boot from an alternate media source, this is another indication that hard drive is malfunctioning. Further attempts to boot the system could seriously reduce the likelihood of a successful data recovery.

If the system can be successfully booted the next step is to attempt to run the data recovery utility. Most utilities work in the same way. The first step the data recovery utility performs is to scan the drive to locate the file system components. Most utilities will display this scan with some type of progress meter. It is necessary to monitor progress and to stay with the hard drive while the utility is operating. If the hard drive starts to make unusual noises stop the scan immediately and power down the computer. The hard drive will need to be sent to us. Another thing that needs to be watched is the rate of progress for the utility. Usually there will be a count of sectors read. The count should steadily increase and it should not stop. If the count or progress does stop the scan should be terminated and the computer powered down. Failure to stop could jeopardize the likelihood of a successful data recovery. The hard drive should be sent to Data Recovery Group.

If there are any signs that the hard drive is failing physically, it is important that software data recovery utilities not be used on the hard drive. Hard drives usually fail gradually and this failure process will be accelerated during a full scan of the hard drive necessary for most data recovery utilities to recover the data.

It is important to read the instructions provided with any data recovery utility you may use on a hard drive. It is important that if you can complete a scan of the failing hard drive that the recovered files are not saved back to the hard drive you are trying to recover. It is possible o save recovered files on the source drive and if this occurs the recovered files could overwrite other files you are trying to recover.

In conclusion, it is very important to determine if a drive has any physical failure before attempting to recover the data using a utility. Data Recovery Group has received many hard drives from customers where the data could have been recovered had we received the drive right after the original failure. Repeated attempts to recover the data with software rendered the drive useless and the data not recoverable.