Hard drive

A hard drive (often abbreviated as HD, or HDD) is a storage device that permanently stores and retrieves data on a computer. It consists of a spinning magnetic disk to which data is written using a read/write magnetic head on a mechanical arm called an actuator, all inside of an air-sealed casing.

Partition and (logical) disk

A partition is an area on a physical storage device separated from other device segments. For the operating system and computer users, although the separation is pure logical, it appears as an independent storage device with a separate file system. There are several reasons for such partitioning. For example, Windows 10 creates several service partitions, apart from the system partition (disk C:), like boot and recovery partitions that it uses to ensure system stability and recoverability. Another reason to separate the system and user data partitions is if the system has to be re-installed, the user data will remain untouched.

To be accessible for the computer user, a partition must have an assigned letter. In this case such a partition is called a logical disk and is referred to by its letter.

SSD and NVME storage devices

Click to expand/collaps SSD Device Icons

A solid-state drive (SSD) is a storage device that stores data on nonvolatile solid-state flash memory and has no moving parts, unlike hard drives or optical disks. They are much faster than traditional hard drives and more shock-resistant, but their life span is shorter and storage space is more expensive. NVME devices are SSD devices connected to the computer through a special interface.

Click to expand/collapse Peculiarities of file recovery from SSD and NVME storage devices

Quick Scan

A disk operation in which R-Undelete quickly analyzes information about files stored on the disk, including search for deleted files. Then it lists all found files in its Files panel.

File mask

A file mask is a pattern of characters and wildcards used to match folder and file names.

File signatures and raw file search

A file signature (sometimes is called as a file magic number) is a data pattern within the file that is unique to certain file types. It can be used to identify the format of the file and recover its content even when the disk file system contains no information about such a file. This method of file recovery is called "raw file search" or search for known file types and used to recover deleted files from damaged, deleted, or re-formatted disks, as well as from partitions with unrecognized file systems. R-Undelete uses raw file search when performing Deep Scan.

Click to expand/collapse List of known file types

Note: Using scan for Known File Types, R-Undelete can successfully recover only un-fragmented files.

Disk Image

An image is a file containing an exact, byte by byte, copy of a hard drive or a disk. When created, images can be connected to R-Undelete and processed like their original objects.

Images are very useful if there is a risk of total data loss due to hardware malfunction. If bad blocks are constantly appearing on a hard drive or its S.M.A.R.T. state is poor, an image of this hard drive should be immediately created. All data search and recovery can be done from this image.

The Disk Images help page explains how to create and work with images.

Smart technology

S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) is a technology widely used in hard drives and solid-state devices that monitors their reliability conditions to predict possible hardware failures.