and you shouldn't be using any of those, since the order can and will change. The numbers are based on the order the devices and device drivers are initialized in, not based on physical location in the system. The modern approach (assuming you're using udev) is to use the symlinks in /dev/disk/by-id/ or /dev/disk/by-uuid/ instead, since both are consistent across reboots (and by-id should be consistent across reinstalls, assuming the same partitioning scheme on the same physical drives)

This is also why Ethernet devices now have names like enp0s3 - the numbers are based on physical location on the bus. The old eth0, eth1, etc. could swap positions between Linux upgrades (or even between reboots) since they were also just the order the drivers were initialized in.

Well it's sdx because they both use the SATA interface. The sdx convention actually comes from scsi though, and the fact that SATA and USB drives use it might point to some code reuse, or maybe a temporary solution that never got fixed due to breaking backwards compatibility.

Fun fact: IDE drives use the hdx naming convention.

A yes, my beloved nvme1p2 partition that changes name every reboot

https://wiki.archlinux.org/title/Solid_state_drive/NVMe

Namespaces are the construct in NVMe technology that hold user data. An NVMe controller can have multiple namespaces attached to it. Most NVMe SSDs today just use a single namespace, but multi-tenant applications, virtualization and security have use cases for multiple namespaces.

  device v
/dev/nvme0n1p1 < partition
namespace  ^

There are two types of people: Those who are able to identify gaps in their knowledge and actively seek to fill them... and whatever this meme is.

nvme0n1p1

https://superuser.com/questions/1449499/why-does-linux-list-nvme-drives-as-dev-nvme0-instead-of-dev-sda#1449520

In short; sd stands for SCSI Disk and SSD and USB all use the SCSI protocol. While SD-cards/emmc (flash-on-CPU) are named emmcblkpX for emmc block device, partition X. And NVME have additionally namespaces, which is the nX part.

It’s called that because it’s Never the Value you Might Expect.

Forgot /dev/hdx ?

Different bus, different naming.

Now, memory kinda hazy, but weren't ide devices /dev/hdX?

I'm guessing it's for some shit to make sure some ridiculous setup with two gazillion drives doesn't have conflicts

No one mentioned the Solaris convention yet ?

/dev/cXtXdXsX

The letters mean controller, SCSI target, disk and slice (Solaris equivalent to a partition).

I always thought this was the most elegant naming scheme in the Unix world.

Mine is easy - /dev/nvme[tab][tab][tab]

Back in the olden times the Linux kernel had a dedicated parallel-ATA subsystem with /dev/hda devices. It was then rolled up in to the scsi subsystem to simplify maintaining drivers (everything using the same library for disk access). I'm old :(

Kinda miss the Wild West days where you'd recompile and suddenly there'd be a whole new device naming convention.

Shouldn't that be

hdX, sdX, and nvmewtfisthisp1

It's a lot better than the system that just randomly throws in your USB drives with your SCSI/SAS/SATA/PATA drives. Or the systems that calls everything a SCSI drive when it usually isn't a SCSI drive.

You mean Linux? Other Unixes don't necessarily use this naming convention.