Arch Linux

Skeleton2323

Member

Registered: 2024-09-14

Posts: 12

Why has the "hda" disk identifier been replaced by "sda"?

Wouldn't it be slightly wiser to keep hda for mechanical HDDs and sda for SSDs?

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 30,261

Website

Re: Why has the "hda" disk identifier been replaced by "sda"?

Huh?  This was never for hdd vs ssd.  Historically the name was based on the controller, hd[a-z] was used for IDE, and sd[a-z] for SATA.  There may potentially have been a correlation between IDE controllers being more common when HDDs were more common - thus a lot of HDDs getting hd[a-z] names, and as time went on more SSDs getting sd[a-z] names, but this is a coincidence, not a label of the type of drive.

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"UNIX is simple and coherent" - Dennis Ritchie; "GNU's Not Unix" - Richard Stallman

Scimmia

Fellow

Registered: 2012-09-01

Posts: 11,984

Re: Why has the "hda" disk identifier been replaced by "sda"?

To be more specific, the 's' in sda stands for SCSI. HDDs have been connected via SCSI for decades and use the 'sd' prefix. When SATA was introduced, it was written on top of the SCSI subsystem, so they inherited the 'sd' prefix. PATA was also migrated to the SCSI subsystem, but kept the 'hd' prefix for historical/compatibility reasons.

cryptearth

Member

Registered: 2024-02-03

Posts: 812

Re: Why has the "hda" disk identifier been replaced by "sda"?

using non-deterministic identifiers in /dev like hd* or sd* is only useful in interactive shells when you first scanned for what identifier belongs to which device
in anything static that has to survive reboots you rather use deterministic identifiers in /dev/disk like one of the by-id or by-path - if you sure you don't have any collisions you can also uee one of the by-label ones

also: https://wiki.archlinux.org/title/Persis … ice_naming
and: https://en.m.wikipedia.org/wiki/Device_ … onventions