Programmer Humor

Restart to find out.

"Couldn't reboot because these programs"

9 of them

"Restart anyway?"

Either that or they were added at different times by two different teams with two different design philosophies.

Incredible intel. Thanks!

"Fun" fact: if you think it's slow normally (and to be fair, it is), NTFS seems to have a pathological performance regression when a directory contains more than 10,000 children, any operations on files in that directory slow down by around 95%.

I discovered this on our CCTV system at work (that runs on Windows Server 2022), which creates an inordinate number of small files (each containing at most a few seconds of video). It was causing some of its periodic maintenance tasks to fail, as they'd take longer to run than than the configured interval between them.

Windows also really doesn't like dealing with half-petabyte filesystems, just like... at all.

Deleting files was an amazing one already. Then I recently discovered the joy of deleting 30k emails from Outlook... T-T

Shift-Del to delete files is usually much faster, though obviously this skips the recycle bin.

To be relevant to the post:

Windows

Someone is using the drive, you can't eject 

Linux

$ umount /mnt
unmount failed: device in use 
$ umount -f /mnt
$ 

My favorite is “Location Not Found”. It’s amazing that both Mac and Linux seem to do a better job on SMB than Windows.

I used to do this, because it didn't seem to cause any issues — until it did, and I lost a lot of data.

Basically, if you, as a regular user, cannot unmount a device, you can usually just go to root shell (sudo -i), see where the thing is mounted (just use mount) and then unmount it (umount /media/blah/floop). If it says the device is still busy, as root you can remount it as read-only and then unmount it (seeking documentation left as an exericise to the reader, as I'm sitting at a Windows system now).

There's also lsof ("list open files") tool, which can be used to see which exact programs are using files on that device, which you can then use to kill those sneaky processes (ps, kill).

Real answer: it depends.

• Deleting a file in use: no problemo. File is removed from the directory immediately, but exists on disk until last program who had the file open closes. Everyone wins! (Unless you're trying to free up space by deleting a huge file that's being held open by a program and not understanding why the filesystem usage didn't go down)
• Unmounting a hard drive in use: Will error out similarly to Windows. lsof can tell you which process has which files open. There's nuance with lazy unmounts and whatnot but that should not be used in most cases.

Now in practice you should be wary of one very important thing that changes compared to Windows: Writes are asynchronous on Linux. First the kernel writes to RAM, then it flushes to disk at a later time for performance reasons (this is one of the reasons why writing a bunch of small files is many times faster on Linux than Windows). The upshot is that just because your file copy is "done" doesn't mean you can just yank the USB cable. Always safely unmount before unplugging a storage device on Linux.

Idk how Linux handles it but today on Mac I accidentally sent a folder to trash that was in use by four programs at once.

Mac OS did not give a shit. It nuked it.

Linux Mint has an eject button that allows any cached writes* to finish, prevents new ones from starting, and un-mounts it. It's actually important to use the eject button as flash drives are slow, and the write cache can obscure the fact that a file isn't done writing yet.

*Copying a file will add it into the write cache while it writes out to the disk. As soon as it is in the cache, you can use the file as if it was already done copying, including making changes.

Many files copied to an external disk are cached, and not written immediately unless you run the "sync" command.

So when you press the "eject" icon, on most frontends a notification will tell you not to unplug it right away, once the write is complete it will send a "it is safe to remove the drive" message. This can take a couple minutes if you are writing a big file to a slow drive.

There is a dirty bit indicating the disk was not ejected properly. It stays there until you use the "scan and fix" action. It doesn't indicate corruption directly.

Told ya, Process Explorer just told me nothing, except Dropbox maybe.

But it doesn't change the usage scenario. I don't care what programs are using the drive. I just need to tell them to fuck off, I need to unplug this drive at this moment.

Windows should just tell you "The file is in use by <actual information here>" by default.