readom

readom [options] dev=target

dev=target
    Specifies the SCSI device or target for the optical drive (e.g., dev=/dev/sr0 or dev=0,0,0). This is a mandatory and fundamental option.

speed=speed
    Sets the read speed for the optical drive (e.g., speed=8).

output=filename
    Specifies the file path where the read data will be written. If omitted, data is written to standard output.

sector=start_sector
    Starts reading from the specified sector number.

sectors=count
    Reads the specified number of sectors from the start_sector.

noerror
    Disables reading with error correction, making the command attempt to read even problematic sectors.

raw
    Reads data in raw mode, including sync bytes and error correction codes. Useful for exact disc copies or forensic analysis.

raw96r
    Reads raw 96-byte sectors including R-W subchannel data.

raw96p
    Reads raw 96-byte sectors including P-Q subchannel data.

cdda
    Reads audio data from an audio CD.

audioscan
    Scans the disc for audio tracks and prints their start and length.

dummy
    Performs a test run without actually reading or writing data, useful for verifying options.

debug=level
    Sets the debug level for more verbose output.

readom is a command-line utility used for reading data from various optical media, such as CD-ROMs, DVDs, and sometimes Blu-ray discs. It's part of the cdrecord or wodim suite of tools, primarily designed for low-level interaction with optical drives.

The command enables users to extract raw data, audio tracks, or complete disc images (ISOs) from optical media. It's particularly useful for creating backups of discs, extracting specific tracks, or performing forensic analysis on disc content. readom can handle different reading modes, including raw reading with or without error correction, and supports various data formats. It interfaces with optical drives typically through SCSI or ATAPI emulation layers, allowing precise control over the reading process. While readom provides powerful capabilities for disc manipulation, its usage often requires understanding of optical media structures and device addressing.

readom typically requires root privileges or appropriate device permissions to access optical drives. It relies on the SCSI subsystem or ATAPI emulation. Its functionality can sometimes be replicated or surpassed by dd for block devices, or by cdrdao for specific CD audio extraction needs. readom is part of the cdrecord / wodim suite, which has seen less development compared to other tools, and its specific behavior can vary slightly across different distributions or package versions. It's designed for low-level access, meaning incorrect usage can potentially damage media or lead to incomplete reads.

readom often requires root privileges or proper sg group permissions to access optical devices directly.

Optical drives are typically accessed via paths like /dev/sr0, /dev/cdrom, or SCSI addresses like 0,0,0. The dev= option must correctly identify the target drive.

Without noerror, readom attempts robust error correction. With noerror, it will read whatever it can, potentially including corrupted data, which is useful for data recovery.

readom emerged as part of the cdrecord project, initially developed by Jörg Schilling. cdrecord was one of the earliest and most comprehensive open-source tools for burning CDs and DVDs on Unix-like systems. readom provided the complementary functionality of robustly reading data from these optical media, particularly useful for creating exact copies or extracting raw streams. Over time, due to licensing disagreements and development directions, cdrecord was forked, leading to wodim (Write Optical Disc Media). readom has largely maintained its original purpose and syntax across these forks, serving as a low-level utility for direct interaction with optical drives. Its importance has somewhat diminished with the rise of GUI-based burning software and the increasing prevalence of USB drives over optical media for data transfer, but it remains valuable for specific niche tasks like disc archival, data recovery, or audio extraction where low-level control is paramount.

wodim(1), cdrecord(1), dd(1), cdrdao(1), mkisofs(8)