page_title: Forensic disk controller
hierarchical_section_title: Forensic disk controller
caption_attribution_description: English: A forensic disk imager. On display at Custom House during Open House London 2015.
context_page_description: A forensic disk controller or hardware write-block device is a specialized type of computer hard disk controller made for the purpose of gaining read-only access to computer hard drives without the risk of damaging the drive's contents. The device is named forensic because its most common application is for use in investigations where a computer hard drive may contain evidence. Such a controller historically has been made in the form of a dongle that fits between a computer and an IDE or SCSI hard drive, but with the advent of USB and SATA, forensic disk controllers supporting these newer technologies have become widespread. Steve Bress and Mark Menz invented hard drive write blocking.
  The United States National Institute of Justice operates a Computer Forensics Tool Testing program which formally identifies the following top-level tool requirements:
  A hardware write block device shall not transmit a command to a protected storage device that modifies the data on the storage device.
  An HWB device shall return the data requested by a read operation.
  An HWB device shall return without modification any access-significant information requested from the drive.
context_section_description: A forensic disk controller or hardware write-block device is a specialized type of computer hard disk controller made for the purpose of gaining read-only access to computer hard drives without the risk of damaging the drive's contents.  The device is named forensic because its most common application is for use in investigations where a computer hard drive may contain evidence. Such a controller historically has been made in the form of a dongle that fits between a computer and an IDE or SCSI hard drive, but with the advent of USB and SATA, forensic disk controllers supporting these newer technologies have become widespread. Steve Bress and Mark Menz invented hard drive write blocking (US Patent 6,813,682).  
  The United States National Institute of Justice operates a Computer Forensics Tool Testing (CFTT) program which formally identifies the following top-level tool requirements:
  A hardware write block (HWB) device shall not transmit a command to a protected storage device that modifies the data on the storage device.
  An HWB device shall return the data requested by a read operation.
  An HWB device shall return without modification any access-significant information requested from the drive.
  Any error condition reported by the storage device to the HWB device shall be reported to the host.
caption: A Tableau forensic disk imager
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