Bitcoin Forum

As per topic. Bitcoin-qt (and the 5+ altcoin clients derived from it that I have installed) will periodically try to access my floppy drive. The light goes on and I can hear the heads chatter momentarily. This happens maybe every 30 minutes, but if I'm running more than one client simultaneously they all do it at different times.

Why is the -qt client trying to access my floppy drive? (and presumably... other drives too, although these would be less obvious)

How did you come to this conclusion and why do you even have such old technology?

Oh my god, you have a floppy drive? May I ask why?

You know, come to think of it, floppy disks would be a good place to backup your wallet. Who the fuck is gonna look there.

Yes, I realise I'm probably one of the last people on this earth to possess and have CONNECTED a floppy drive. :) I keep it for the occasions where it totally hits the fan; recently did a BIOS update via floppy because I couldn't get it to recognise any of the USB sticks I had.

However, that's beside the point. The question is - why is the client hunting around for data on other drives?

Floppy drives, stopped being cool in 1998, started being cool again in 2013.

I totally want to transfer data to my airgapped boxes using floppies, easy to hear when accessed, easy to fill with random junk so no malicious data crosses the gap, trivial to destroy: kill it with fire.

5 internets to you OP.

For your question, no idea, that seems really weird. Getting other people to confirm this behaviour might be slightly tricky :-)

And I ask again, how did you come to this conclusion? Why do you think it's the -qt client? Also, Windows XP is old and has many exploits.

The phantom floppy access attempt only happens when I have a -qt client running.

I just restarted the Bitcoin client and it tried to access the floppy twice at startup.

my biggest problem is that you have a wallet on an XP box...that is just asking for it

Disregard the morons questioning your question.

If you really want to get to the bottom of this I'd try :
 - asking #bitcoin-dev
 - moving the floppy unit to another computer try to confirm the behaviour
 - trying from the same computer on a different OS

Are you positive you have no viruses on your box?
Maybe it could be some sort of malware looking for a *coin-qt process and scanning all disks for wallet files.
Do you keep balances on the clients ?
Do you get the same behaviour with your CD drive if any ?

mmmmmmmmmk

This.  OP care to share how you determined it is QT client making the disk access?  Or is this one of those "X happens and I have QT client installed therefore the QT client caused X" type assumptions?

Wouldn't worry about it.  Most likely some component within the Bitcoin client is doing a generic enumeration of drives on the system or calling an API which does this as a side effect.  This causes the floppy controller to check whether there's a disk in the drive to gather stats such as free space and so on.  Does not necessarily mean it's actually trying to read any files on the drive.

Similar weird accesses might also be seen if you have the drive letter as part of some environment variable path list.

Yes, I figured it was probably some obscure or not well documented function buried deep within a linked library, rather than the client code explicitly trying to access a file. If I understand correctly, PC floppy drives are rather dumb - no signal to say that a floppy is present - so they can only detect a disk change (or an empty drive) by spinning up and trying to read data. That's why I can hear and see the access.

I thought it may have been some strange interaction with my A/V program, but disabling that hasn't changed the behaviour.

I'm not really that concerned, but I did think it was odd, particularly because no one else seems to have asked this question. It gets pretty strange when you're running several -qt clients simultaneously... the drive chatters away every few minutes.

Does anyone know offhand what periodic maintenance job the Bitcoin client might be scheduling every 30 minutes or so?

Yep.

If you wanna do some sleuthing, Process Monitor (and the other Sysinternal utilities) can likely give you the culprit, or at least some clues as to the context of the disk access:

http://technet.microsoft.com/en-us/sysinternals/bb896645

There is absolutely no reason for Bitcoin-Qt to ever access your floppy drive unless you explicitly tell it to (eg, save a wallet backup to a floppy disk). The only thing I can think of is that the large memory and/or hard disk usage might be screwing with Windows' disk cache management or something.

Some kind of disk flushing maybe?

Where did you get the Bitcoin client from? The only executables I have encountered so far that would access an FDD periodically were either malware scanners or malware...

Thanks for that.

https://i.imgur.com/N2MP5NK.png

Now do people believe that bitcoin-qt.exe is accessing my floppy drive? :P

F, G and S are also valid & writeable drives.

I'm not really familiar with Windows debugging but it looks like the call chain that generated this activity is bitcoin-qt->advapi32.dll->perfdisk.dll. Possibly an API32 function to get connected drives or similar?

Just a long shot, but advapi32 mostly contains crypto related primitives, including the strong RNG. I'm guessing it's just trying to poll various sources of physical entropy (including disk drive performance counters)

+1 Especially the 5.25in variety.