HDDSuperClone vs ddrescue

GNU ddrescue and HDDSuperClone are open-source tools for imaging a failing hard drive. Both create a sector-by-sector binary clone of a source disk. Both can pause, resume, and work around bad sectors.

The difference is in how they reach the drive. ddrescue reads through the Linux kernel's block device layer. HDDSuperClone's passthrough modes go through the Linux driver too, but its direct IDE and AHCI modes bypass all Linux OS drivers.

Some drives are a job for ddrescue and some need HDDSuperClone. Some are past both tools and need professional hardware like the PC-3000 or DeepSpar Disk Imager.

ddrescue

GNU ddrescue (version 1.30, January 2026, GPLv2+) is a multi-pass block imager written by Antonio Diaz Diaz and distributed by the GNU Project. It reads sectors from a failing source device through the Linux kernel block layer (/dev/sdX), copies them to a destination disk or image file, and records the state of every sector range in a mapfile. The algorithm runs in five distinct phases: copying, trimming, sweeping, scraping, and retrying.

Version 1.30 added the sweeping phase, which replaced the old fifth copying pass. The 1.30 release notes say all of that version's changes together let it recover a drive with a dead head, with orders of magnitude fewer read errors than 1.29. ddrescue isn't firmware-aware. It can't issue ATA pass-through commands, knows nothing about physical head-to-LBA mapping, and can't power-cycle a locked drive.

ddrescue isn't the same program as dd_rescue by Kurt Garloff, and it isn't the standard dd utility either. If the drive clicks or grinds, stop ddrescue and get the drive to a clean bench. Keep imaging a clicking drive and it scrapes magnetic coating off the platters, which ends the recovery.

Critical ddrescue parameters for failing hard drives

• Mapfile resumability. Always pass a mapfile path as the third argument. ddrescue marks finished sectors as +, non-tried as ?, non-trimmed as *, non-scraped as /, and bad-sector as -. Resuming with the same mapfile re-reads only unresolved ranges.
• --min-read-rate (-a). If the read rate of good non-tried areas falls below this value during the first two passes of the copying phase, ddrescue skips ahead and tries the skipped slow areas later.
• -r N and -R. The retry count defaults to zero. A first pass with -n (no scrape) grabs easy data. A second run with -r 3 goes on to scrape the remaining blocks and then makes up to three retry passes over the bad sectors, reversing direction after each pass. -R reverses the direction of every pass.

If the heads have failed, none of these flags will help, and the drive needs a head swap. We do helium drives in-house at the Austin, TX lab too, including head swaps and helium refill.

What is ddrescue?

GNU ddrescue is a block-level disk imaging tool written by Antonio Diaz Diaz and distributed by the GNU Project under the GNU General Public License. It reads sectors through the Linux kernel's block device layer, copies them to a destination file or disk, and records progress in a mapfile so the run can be paused and resumed.

Its multi-phase algorithm copies the easy data first, then trims, sweeps, scrapes, and retries the unresolved sectors. The -r N flag controls retry passes on bad sectors; the default is 0, and a triage pass on a failing drive typically uses -n first (no scraping) followed by -r 3 on a second run.

ddrescue isn't firmware-aware. It doesn't issue ATA pass-through commands and knows nothing about physical heads.

What is HDDSuperClone?

HDDSuperClone is a disk imaging tool originally written by Scott Dwyer, known on HDDGuru and other data recovery forums by the handle "maximus." Dwyer released the PRO version as freeware in 2022, open-sourced the code under the GNU General Public License, and ended commercial development; the actively maintained fork is OpenSuperClone, hosted on GitHub.

Unlike ddrescue, it talks to the drive with SCSI passthrough commands. The former Pro version adds direct I/O for IDE and SATA drives. Its skip gets wider while errors keep coming, so it steps over an error-dense region instead of grinding through it sector by sector. It has no head map, and it never works out which head produced the errors.

It runs only on Linux. It exposes its imaging session as a virtual block device that file-system parsers like DMDE or R-Studio can read, and supports YKUSH USB relays for automated power cycling on locked-up drives.

Disk Imaging Is Not Data Recovery

A common error in DIY recovery attempts is running file-recovery software (Recuva, EaseUS, Disk Drill) directly on a failing drive.

File-system parsing happens on the cloned image, not on the original drive. ddrescue and HDDSuperClone are imaging tools. They output a raw binary image or a cloned disk. They do not output readable files.

GNU ddrescue: Kernel Block Device Imaging

GNU ddrescue is a GNU Project tool that reads from the standard Linux block device interface (/dev/sdX).

ddrescue's strength is its multi-pass algorithm. As of version 1.30 (January 2026), five phases handle progressively harder sectors:

1. Copying: Reads large blocks in up to four passes, skipping beyond failed blocks and slow areas so the easy-to-read data comes out first.
2. Trimming: Goes back to the edges of the large block reads that failed during copying and reads sector by sector, forward from the leading edge and backward from the trailing edge, until it finds a bad sector.
3. Sweeping: One pass with skipping disabled that copies the non-tried areas the copying phase skipped because of read errors.
4. Scraping: Reads the remaining unresolved sectors one at a time.
5. Retrying: Optional passes over the bad sectors, one try per sector per pass, reversing direction after each pass.

The mapfile (formerly logfile) records the state of every sector range as non-tried, finished, non-trimmed, non-scraped, or bad-sector. If the process is interrupted by a crash or a drive dropping offline, ddrescue resumes from the mapfile without re-reading finished sectors.

Where ddrescue works well

Drives with stable, functioning read/write heads but scattered bad sectors from media degradation. The heads can still read the majority of the platter surface; the bad sectors are localized defects in the magnetic coating. ddrescue extracts the good data first, then methodically narrows down the bad regions.

Where ddrescue fails

When a physical read/write head is weak or intermittently failing, ddrescue has no mechanism to detect which head is responsible. The Linux kernel treats the drive as a single block device.

If a bad head hangs the drive controller, the kernel waits for its I/O timeout (30 seconds by default) before returning an error. While the kernel waits, the drive's firmware is retrying the read internally and doesn't answer the host. ddrescue can't issue a hardware reset.

HDDSuperClone: ATA Pass-Through Imaging

Scott Dwyer originally developed HDDSuperClone. It talks to the drive through SCSI or ATA passthrough, which still goes through the Linux driver, or through its direct IDE and AHCI modes, which bypass all Linux OS drivers. He argues for passthrough because of the feedback it gives. It can tell when a drive is no longer responding properly, where ddrescue only gets a read error back from the OS.

Head-skipping algorithm

A hard drive maps logical block addresses (LBAs) to physical platters and heads, and HDDSuperClone never sees that mapping. Its self-learning head skipping algorithm works from read errors: the first error triggers a skip of --skip-size, and the skip grows as errors continue until reads succeed again or until it reaches --max-skip-size, where it stops increasing. Its author says it's designed to try to skip out of a bad head in about seven bad reads. The software never learns which head it escaped.

In practice, the error-dense region gets left for a later, slower pass. That's a blunt approximation of what the PC-3000 does at the firmware level, where the operator works from the drive's real head map instead of an error pattern.

Virtual disk mode

HDDSuperClone can present the imaging session as a virtual block device to the host operating system. File-recovery software (DMDE, R-Studio) can then target specific structures like the Master File Table. If the requested sectors have already been cloned, HDDSuperClone serves them from the image file. If not, it reads them from the source drive and copies them to the destination, so any further read of the same data comes from the image. That lets you recover specific files without finishing a full-disk clone.

OpenSuperClone: the actively maintained fork

Scott Dwyer, HDDSuperClone's original developer, released the source code and stopped active development. The project lives on as OpenSuperClone, maintained under the ISpillMyDrink account on GitHub. OpenSuperClone installs its OSCDriver kernel module through DKMS, and OSC-Live, a live ISO the community built, runs it from a USB stick.

Automated power cycling with USB relay hardware

Severe read instability can lock a drive controller so completely that ATA soft resets and bus resets both fail. At that point, the last resort is cutting the drive's power. OpenSuperClone can drive generic USB HID relay boards and YEPKIT YKUSH switchable USB hubs to power-cycle a drive. A SATA drive needs two relays to switch both its 5V and 12V rails. A USB-attached drive runs on a single 5V rail, and a YKUSH hub switches that rail along with the port's data lines.

Side-by-Side Comparison

Why Windows Is the Wrong Operating System for Disk Imaging

Windows writes to mounted storage devices on its own to update or repair file-system metadata. On an unstable drive, those writes can cause permanent data loss.

Both ddrescue and HDDSuperClone run on Linux, which can be configured to avoid auto-mounting. For drive imaging, the source drive should never be mounted.

Is There a Windows Version of OpenSuperClone?

OpenSuperClone is a Linux program. So was HDDSuperClone, the abandoned tool it forks from. Neither project ships a Windows installer, so there is nothing to install under Windows. For a Windows user with no Linux machine, the path is a Linux live USB.

OSC-Live is that image. Write it to a USB stick and boot the machine from the stick. The numbered OSC-Live boot sequence spells out what the destination drive needs.

Booting that stick doesn't install anything onto the Windows machine and doesn't modify the Windows installation on its internal disk. The whole environment runs off the USB stick. The failing drive is attached as the source and is left unmounted. The clone lands on a separate healthy drive of equal or greater size. Never a partition on the source.

A live USB changes the host, not the drive. If it clicks or grinds, booting Linux instead of Windows buys nothing. That is a mechanical or firmware fault, and no imager gets a usable read until it is fixed; a head swap runs on the 0.02µm ULPA-filtered clean bench. That work runs in-house at our Austin, TX lab, and the published pricing for a mechanical hard drive recovery covers the head swap and the imaging that follows it.

When Both Tools Fail: The Physical Failure Boundary

• Clicking or clacking: The drive cannot find the servo tracks on the platter surface. The actuator swings outward, fails to lock onto a track, and retracts to the crash stop. Damaged heads produce that; so does firmware the drive cannot read, a dead preamp, and a board carrying the wrong adaptive parameters. Each cycle risks contact between the head slider and the platter, whichever of them is behind it.
• Firmware corruption: If the drive's Service Area is damaged, the drive may report 0 bytes capacity. Software imaging tools can't access or repair the Service Area.

What professional tools do differently

Once a drive has failed physically like this, getting the data back means opening it in a 0.02µm ULPA-filtered clean bench for head swaps with a matched donor, or connecting it to the PC-3000 for firmware repair. PC-3000's MR-Head Shift removes a dead head from the drive's initialization so we can read the heads that are left.

If your drive exhibits any of the symptoms listed above, mail-in recovery is the next step. We charge no fee if the data is unrecoverable.

Choosing the Right Approach

If the drive spins up, is recognized by the BIOS, and produces no abnormal sounds, start with GNU ddrescue. It is simpler to configure, media-agnostic, and handles scattered bad sectors efficiently. Use a Linux live USB, connect the source drive via SATA (not USB, which adds a bridge controller that masks ATA errors), and image to a destination drive at least as large as the source.

If the drive clicks, grinds, shows 0 bytes in BIOS, or fails to spin, stop. No software will help. The drive needs to go to a professional lab.

Where Does DeepSpar Disk Imager Sit Between OpenSuperClone and PC-3000?

DeepSpar Disk Imager (DDI) is a dedicated imaging appliance rather than a general-purpose software tool. DDI and the PC-3000 work at different levels of the drive. DDI handles the drive at the SATA PHY and host layer, with its own read timeouts, resets and power cycling. PC-3000 works inside the drive's firmware.

DeepSpar says DDI processes every head differently depending on how degraded that head is, with customizable algorithms for different hardware and media issues.

OpenSuperClone's head-skipping algorithm works from read errors and slow reads. It has no head map. Neither DDI nor OpenSuperClone does firmware surgery, so a drive that needs a translator rebuild or SA module patching still goes to PC-3000.

How Do SMART Attributes Inform Imaging Strategy?

Before starting any imaging session, read the drive's SMART attributes with smartctl -A. Start with these four:

• Reallocated Sector Count (ID 5): sectors the drive has already swapped out to the defect list.
• Current Pending Sector Count (ID 197): sectors the drive has flagged for reallocation but has not yet rewritten.
• UDMA CRC Error Count (ID 199): errors in data transfer over the interface cable, not platter errors. A rising UDMA CRC count during imaging points at the SATA cable or connection. Stop, replace the cable, and re-seat the drive.
• Spin Retry Count (ID 10): retried spin-up attempts. A rising value is a sign of problems in the drive's mechanical subsystem.

The operator should read these attributes before starting a session, not during it. DDI can suppress the drive's SMART subsystem during imaging so the drive isn't writing to its Service Area mid-image.

ddrescue doesn't read SMART. OpenSuperClone can request SMART data from the source drive and display the results.

Imaging Parameter Tuning for Failing Drives

Both ddrescue and OpenSuperClone accept parameters that control how aggressively they pursue unreadable sectors.

ddrescue parameter strategy

The --min-read-rate flag sets a minimum read rate, in bytes per second, for good non-tried areas. If the read rate falls below it during the first two passes of the copying phase, ddrescue skips ahead and tries the skipped slow areas later.

The --reverse (or -R) flag reads the drive from the last LBA backward toward LBA 0.

The -c flag controls cluster size (the number of sectors read per I/O request). The manual suggests smaller values for slow drives.

Direct I/O mode for unbuffered reads

ddrescue's --idirect (short -d) makes the input use direct disc access, bypassing the operating system's buffer and page cache. --odirect (short -D) does the same for the output. That matters on a failing drive.

The manual says the reason is granularity. If the positions and sizes in the mapfile are always multiples of the sector size, the kernel may be caching and grouping disc accesses. Direct access to the input rescues more of the data. You have to set the sector size correctly with --sector-size for direct access to work, and not every system supports it.

Direct I/O still runs through the Linux kernel block layer. It does not make ddrescue firmware-aware. It can't issue ATA pass-through commands, can't detect a failing physical head, and can't power-cycle or firmware-reset a hung drive. A clicking or head-degraded drive still needs hardware imaging on a PC-3000 Portable III or DeepSpar Disk Imager, and where the heads are gone, a clean-bench head swap in our Austin, TX lab.

OpenSuperClone parameter strategy

OpenSuperClone's skip threshold is a read time in milliseconds. In phases 1 and 2, any read that takes longer triggers a skip. It doesn't cut the read short.

HDDSuperClone Pro is free now. It can perform soft and hard resets on unstable SATA and PATA drives using timeouts, and when a relay is wired for it, it can power-cycle a drive that stops responding.

How to install and run OpenSuperClone

1. Download the OSC-Live ISO (the OpenSuperClone README links it) and write it to a USB stick.
2. Boot the target machine from that USB stick.
3. Connect the source drive by direct SATA where possible, then launch the imaging session, writing to a healthy destination of equal or greater size.
4. Let it build its progress log, then export a ddrescue-compatible mapfile from that log. You can hand that mapfile to ddrescue for the final scrape and retry passes.

All of this assumes the drive still images. If it clicks, grinds, or reports 0 bytes, no software imager helps. The heads or firmware have failed, and the drive needs the 0.02µm ULPA-filtered clean bench and a PC-3000 instead of another imaging attempt.

Head Instability Detection and Adaptive Imaging

HDDSuperClone doesn't detect which head is failing. Its self-learning head skipping algorithm reacts to read errors. It skips forward on the first error, widens the skip as errors keep coming, and is designed to try to skip out of a bad head in about seven bad reads. Nothing in that process records a head number, a head boundary, or a zone.

That's still useful. The imager clears an error-dense band quickly instead of dwelling on it, secures what reads on the first passes, and returns to the skipped ranges once the easy data is already on the destination drive. It buys the drive time. It doesn't diagnose the head.

ddrescue skips on error too, but it never sees the ATA error register that says why a read failed. The Linux kernel's block device layer shows it the drive as a flat run of logical blocks, with no physical geometry information.

When ddrescue retries bad sectors, it can't tell whether the errors come from media defects or a failing head.

PC-3000 reaches a layer neither software tool can get to, the head map itself. Its MR-Head Shift removes a dead head from the drive's initialization so we can read the heads that are left.

Combining ddrescue Mapfile Semantics and HDDSuperClone Skip Behavior on Degrading PMR/CMR Drives

On a Perpendicular Magnetic Recording (PMR) or Conventional Magnetic Recording (CMR) drive with one weak head and otherwise healthy platters, the choice between ddrescue and HDDSuperClone is not exclusive.

ddrescue mapfile state machine

The ddrescue mapfile (renamed from logfile in version 1.20) is a plain-text record of every byte range on the source drive and its current status. The state machine uses five single-character status codes:

• ? non-tried: ddrescue has not yet attempted these blocks; the copying phase targets them first.
• + finished: blocks already read successfully and copied to the destination; never re-read from the source on resume.
• / failed block non-scraped: blocks that survived the trimming phase and await sector-by-sector scraping.
• * failed block non-trimmed: blocks that failed the initial copying phase and have not yet had their edges trimmed inward sector by sector.
• - failed block bad-sector: blocks with sectors marked bad during trimming, sweeping, or scraping. These are the targets of the retry passes (-r3 requests three retry passes); in fill mode they can be overwritten with a marker string to identify which files lost data.

The mapfile also stores a status line with the current byte offset, current operation character, and current pass number, so a session interrupted by a crash, a kernel panic, or a drive dropping offline resumes at the exact pass and direction it was running. The mapfile is sequential and head-blind: every status entry refers to a contiguous byte range with no awareness of which physical head services that range.

Reading ddrescue mapfiles with ddrescueview

ddrescueview is a graphical viewer that parses a ddrescue mapfile and paints every block onto a grid, coloring each cell by its status code. An operator sees at a glance where finished (+), non-tried (?), non-trimmed (*), non-scraped (/), and bad-sector (-) regions cluster across the LBA space, rather than reading the raw text log by hand.

HDDSuperClone progress log and adaptive command timeout

HDDSuperClone and its actively maintained fork, OpenSuperClone, record imaging state in a progress log. Each entry carries the starting LBA of a block, its size in LBAs, its status, and the skip and error detail behind that status. There's no head field, because the software never works out which head it's reading.

The self-learning head skipping algorithm feeds that log. On a read error it skips forward by the current skip size and keeps enlarging it while errors continue. Its author says it's designed to try to skip out of a bad head in about seven bad reads. The phases work from the same record: a forward pass with skipping, a backward pass with skipping, a pass that skips on read rate rather than read errors, and a pass without skipping over whatever was never tried.

The second architectural difference is timeout granularity. When ddrescue issues a kernel read, the request is governed by the Linux SCSI error handler. The default block-device I/O timeout is 30 seconds.

If the timeout fires, the SCSI error handler runs its own reset escalation before the read returns to user space, which adds more time the imager cannot control.

While ddrescue waits, the drive's firmware is retrying the read internally and doesn't answer the host. ddrescue can't interrupt that wait through the kernel.

HDDSuperClone Pro doesn't wait on the kernel error handler. It performs its own soft and hard resets on unstable SATA and PATA drives using timeouts. If the drive stops responding, it can power-cycle it through a relay wired for the purpose.

Why this matters on a degrading PMR or CMR drive

HDDSuperClone skips out of the error-dense band quickly, images what reads on the first pass, and only goes back to the skipped ranges once the safe data is secured.

Pricing for hard drive data recovery at the head-swap tier starts at $1,200–$1,500. Donor drive cost is additional (Donor drives are matching drives used for parts. Typical donor cost: $50–$150 for common drives, $200–$400 for rare or high-capacity models. We source the cheapest compatible donor available.). +$100 rush fee to move to the front of the queue is available when timing matters.

How Does PRML Read Channel Tuning Recover Marginal Sectors?

When a drive packed with bad sectors has a weak head and won't return data, it comes down to whether you can get the drive's analog read channel to decode the signal on a different set of rules. That layer is out of ddrescue's reach. That's why mechanical hard drive data recovery with PC-3000 gets data that open-source imagers give up on.

PC-3000 retunes the read-channel adaptives per head

PC-3000 reaches the adaptive parameters the drive normally keeps private. On Western Digital ROYL drives, Module 47 holds the per-head microjog and servo adaptive parameters.

The technician can retune the FIR equalizer taps so a degraded waveform still resolves against the target response, or raise the VGA gain on a weak head. Sectors that the stock parameters cannot resolve sometimes read after retuning.

Drive-Family-Specific Imaging Strategies

Different HDD families have unique firmware behaviors that determine which imaging tool is appropriate.

Seagate F3 translator damage

Seagate drives using the F3 firmware architecture store their LBA-to-physical translator in System File 28 of the Service Area. When this system file corrupts, the drive reports 0 GB capacity to the BIOS. Neither ddrescue nor OpenSuperClone can image a drive with no valid LBA mapping because there are no addressable sectors to read.

PC-3000 connects to the Seagate diagnostic terminal (a serial interface on the drive's PCB) and regenerates the translator using vendor-specific commands. This is firmware surgery that no software imaging tool can perform.

Western Digital encrypted external drives

On Western Digital's Spyglass family of external drives, the USB 3.0 interface and a Self-Encrypting Drive (SED) AES engine are built right into the drive's main Marvell microcontroller unit. There is no separate bridge chip, and the native USB PCB has no SATA connector, so a plain board swap does not by itself produce a readable drive.

When the native USB board fails, we move the drive onto a compatible SATA donor board with a ROM transfer. The wrapped encryption key sits in Service Area modules, such as Module 25 or 38, and PC-3000 extracts it with vendor-specific commands.

When PC-3000 Data Extractor Is Required

When software imaging tools reach their architectural limits, professional hardware provides firmware-level access that no software can replicate. The following failure modes require PC-3000 intervention because the drive's own firmware blocks access to the data at a level below the operating system.

Self-encrypting drives with the key in the Service Area

Without the credential, there's no generic way into self-encrypting drives as a class. What exists is vendor-specific. On WD drives, the wrapped encryption key sits in Service Area modules, such as Module 25 or 38, and PC-3000 extracts it with vendor-specific commands. A Seagate F3 drive with a locked diagnostic port needs a RAM patch to get terminal access back, and that patch doesn't decrypt any user data. Outside those documented paths the drive stays encrypted, and no imager changes that.

Thermal asperity and degraded read heads

A thermal asperity event occurs when a read head's magnetoresistive element makes intermittent contact with the platter surface, generating heat spikes that distort the read signal. PC-3000 can retune the read-channel adaptives on the affected head, and sectors that the stock parameters cannot resolve sometimes read afterwards.

Diagnostic port locks on Seagate F3 drives

Newer Seagate F3 families ship with the diagnostic terminal locked, so the T> prompt does not accept commands. PC-3000 dumps the SPI ROM and injects a volatile RAM-resident unlock patch. That restores diagnostic-terminal access for Service Area repair. It doesn't decrypt user data, and it doesn't get past SED or ATA password locks.

Head map editing on a drive with a dead head

A drive with one destroyed head on its head stack assembly can still hold every byte the customer needs on the surviving surfaces, and the obstacle is that the firmware keeps selecting the dead head. PC-3000's MR-Head Shift removes the dead head from the drive's initialization and substitutes an adjacent head for it, so we can read the heads that are left. ddrescue and OpenSuperClone have nothing like it. It takes vendor-specific firmware commands.

If your drive has any of these firmware-level failures, it needs professional hard drive recovery with PC-3000 hardware.

Frequently Asked Questions

If your drive has crossed the boundary where software imaging tools fail, professional hard drive data recovery or SSD data recovery starts with a free diagnostic. Drives showing the SATAFIRM S11 firmware failure need PC-3000 hardware. We charge no fee if recovery isn't possible. HDD head swap recovery starts at $1,200–$1,500.