ENOMEDIUM
Linux / POSIXERRORNotableDeviceHIGH confidence

No Medium Found

Production Risk

Expected when handling removable media; always check for media before operations.

What this means

ENOMEDIUM (errno 123) is returned when a removable media device (CD/DVD drive, tape drive, floppy) has no media inserted.

Why it happens
  1. 1Opening or reading a CD/DVD drive with no disc inserted
  2. 2Accessing a tape drive with no tape loaded
  3. 3Operating on a memory card reader with no card
How to reproduce

open() on a CD-ROM drive with no disc.

trigger — this will error
trigger — this will error
int fd = open("/dev/sr0", O_RDONLY);
// Returns -1, errno = ENOMEDIUM if no disc inserted

expected output

open: No medium found (ENOMEDIUM)

Fix

Insert media before accessing the device

WHEN When accessing removable media devices

Insert media before accessing the device
# Check if media is present using udev
udevadm info /dev/sr0 | grep ID_CDROM_MEDIA
# Or check with blkid
blkid /dev/sr0

Why this works

Use udev or blkid to detect media presence before attempting to open the device.

Sources
Official documentation ↗

Linux Programmer Manual errno(3)

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