Ubuntu which sda

It is possible for secondary and external hard drives to be named sda — Devon. Yes, these are probably laptops with internal nvme SSD drives.

Those weren't very common when this answer was written, they have become much more common now. Gabb3 Gabb3 4 4 bronze badges. Kyle H Kyle H 1, 6 6 silver badges 7 7 bronze badges. Jayden W. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta. Now live: A fully responsive profile. Linked Related 2. Hot Network Questions. Question feed. A metaphor is usually related in some sort of tangential way that is more closely related to the addressee's experience than the concept or thing one wishes to explain.

So one might explain the workings of a processor in terms of tractors and muddy boots to a farmer, for example. The hope is the addressee will be able to utilise the symbolic link s in order to mentally construct a working model of whatever the addresser is describing, without first-hand knowledge. So it's only really a lie in the same way a block-chain is a lie about a pass-phrase.

In fact, a blockchain is a sort of metaphor. Shadur what if on df -h I see sda and sde but not sdb? Show 5 more comments. Rory Alsop Rory Alsop 3, 19 19 silver badges 31 31 bronze badges. Tom Yan Tom Yan 6, 2 2 gold badges 12 12 silver badges 32 32 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog.

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Now live: A fully responsive profile. So you could have a disk whose only partition is sda9, for example. Trying to open the device file for a nonexistent partition will fail, of course. It's possible to forego partitioning and put a filesystem directly on a disk.

When you mount a block device, the filesystem driver typically looks for a superblock at a predetermined offset from the beginning of the device, and since the beginning of a partition is not the beginning of the disk itself, the superblock for a filesystem in a partition is located at a different place on the disk than the superblock for a filesystem created on the "whole-disk" device.

So if the disk used to just have a filesystem, and then it was partitioned and a filesystem was created in a partition, the old superblock might still be there, e. So the disk still appears to have a filesystem on both the raw disk device and on the partition device, because whichever one you try to mount, when the filesystem driver goes looking for the superblock it'll find one. It's not actually safe to mount and use both filesystems, though, since they overlap on the disk. One may have important bookkeeping data in what the other thinks is free space.

That's why it's a good idea to zero the beginning of a block device, to remove any unwanted superblocks, when you want to change a raw disk to a partitioned one, or vice versa, or change the type of filesystem used on a partition, etc. As far as I know, when the kernel detects a new block device on a scsi-like incl.

If there are readable partitions, it will then create the partition nodes numbered depending on whether they're physical or logical partitions I believe logical partitions start at 5. If you see a disk node but with no partition nodes, this would mean that there haven't been any partitions detected.

I'm not aware of any instance where you can mount the physical device, as that would imply that there's a filesystem directly written to the physical device without any partition table. One interesting difference is that if a device has partitions has MBR data or sth alike you can't read MBR data from any of the virtual devices, as MBR data resides outside of any partitions on a device.

There is a good practice to create the first partition at 1MiB after the beginning of a device. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Asked 9 years, 11 months ago. Active 5 years, 4 months ago. Viewed 59k times. And why can I mount both?