Why is Hotplugging Bad?
 

Hi everyone.
I am a little confused as to why hot plugging is bad. I thought that hotplugging was only an issue with devices that carry power, but wikipedia says that even hotplugging rca cables is bad. Can someone shed some light on this for me?

A link and quote from the relevant Wikipedia article would be helpful.

I assume you are referring to USB devices. I have heard of hotswapable hard drives, but that's usually an IT Dept. thing that most of us regular users don't get involved in. That's something I've never dealt with.

As far as I know, there is nothing wrong with hot plugging or hot swapping USB devices as long as one remembers first to shut down the device to be removed using a "safely remove" or an "umount" command. Otherwise, disconnecting a device could result in corrupting the data on the removable device if a file is actively being transferred or read at the time the device is removed.

At least, that's what gurus have told me.

I know of cases where persons who just yanked a USB device out of the computer destroyed files on the removable device. I haven't personally known of the device's being rendered unusable, just individual files.

YMMV.

Yeah, need some more info on what exactly it is you think is bad with hot swapping. As ^ stated, as long as the process is followed data should not be corrupted.



What does that even mean? What devices are they talking about?

Hotplugging pretty much everything except USB items is bad.

Why? Because USB is specifically designed to be hotplugged.

Nothing else is.

I hope this answers your question.

Not necessarily. You can get anything if you are prepared to pay.
Enterprise systems allow hotplugging of everything - CPUs and memory included.

If used properly, i.e. responsibly and carefully, hotplugging is NOT bad. It's true that USB is designed for it while other devices, maybe not.

Why exactly do you need to hotplug ? If you don't need it don't use it, but if you need it, use it carefully.

eSata devices, mainly for the external hard disks, with suitable connectors are supposed to be hotplugable.

Yes, RCA aka phono jacks or stereo jacks were not designed to be hot plugged. It is due to the center pin i.e high signal mating before the ground (ring). It is possible to blow a speaker if the volume were turned up but should not really be a problem with low level signals like video. Ok, I've never had any video equipment fail.

Neither PS/2, RS-232 or the printer port are technically hot pluggable. I have hot plugged RS-232 and never had anything bad happen. However, one of my friends blew a PS/2 keyboard controller which I believe was due to electrostatic discharge (ESD). With IDE, SCSI, SATA the controller and hardware must be designed for hot plugging.

Power is not the only issue. You also need to protect the data signals from ESD.

I still don't understand why wouldn't you hot-plug and RCA jack? It's just a low-voltage audio signal, no power or anything.

EDIT: michaelk's post wasn't there when I started writing this!

I read about the PS/2 protocol and it says that the computer can hang if the signal is disconnected white data is going through. And I have hot-plugged PS/2 keyboards and mice before, and sometimes you have to reboot to get it to work again. But then I thought what if you just leave the keyboard/mouse alone for a minute before unplugging? And it works.

It seems to me that really what is of concern when hotplugging (ps2 as an example) is esd. But, esd is a problem whether the machine is on or off.

The only things I hotplug are USB devices, network cables, RCA TV A/V cables (like the ones that come with a VCR/DVD player/video game console), and ⅛" stereo jacks.

I don't hotplug PS/2 cables, RS-232 serial cables, or VGA/DVI display connectors.

D-Sub aka VGA
 

What about D-Sub?

What's D-Sub?

http://en.wikipedia.org/wiki/File:SVGA_port.jpg
Was before DVI.

D subminiature connector.
http://en.wikipedia.org/wiki/D-subminiature

Which also includes printer and serial ports.