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  #1  
Old 10-27-2005, 10:58 AM
KlondikeGeoff KlondikeGeoff is offline
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OK to disconnect ethernet cable w/computer on?

It's nice to be able to connect and/or disconnect USB cables without having to shut down the computer. I know you should never do this with any other connections while computer is on.

However, am wondering whether can disconnect/connect an ethernet cable from my computer to an external modem (for cable broadband) without any harm?

As use a router between the modem & computer, same Q aplies to this.
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  #2  
Old 10-27-2005, 11:06 AM
Nanoda Nanoda is offline
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Sure, no problem. At worst you'll have to re-request an IP address when you plug the cable back in (Start -> Control Panel -> Network -> Right-click -> Repair in Windows XP).

Most computer cables you can plug/unplug with wild abandon with no ill effects: serial, parallel, midi... I suppose I'm not a fan of loud humming when messing with speaker cables, but that's never been a problem for me either.
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  #3  
Old 10-27-2005, 11:56 AM
633squadron 633squadron is offline
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Quote:
Originally Posted by KlondikeGeoff
It's nice to be able to connect and/or disconnect USB cables without having to shut down the computer. I know you should never do this with any other connections while computer is on.

However, am wondering whether can disconnect/connect an ethernet cable from my computer to an external modem (for cable broadband) without any harm?

As use a router between the modem & computer, same Q aplies to this.
Should be absolutely no problem. Ah, progress... Back in the days of token-ring networks based on coax, if you disconnected the connector from your own computer you crashed the entire LAN And I mean crashed it. Major anxiety.

But of course, token ring was a Dumb Idea. Ethernet is pretty darn good. I'm waiting for live HD TV/Video wirelessly everywhere in the world, and the ability to run a HDTV web conferencing app on my computer at work in Cupertino, CA from a tablet PC in Philadelphia with no lag time. 5 years?
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  #4  
Old 10-27-2005, 11:58 AM
engineer_comp_geek engineer_comp_geek is online now
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Quote:
Originally Posted by Nanoda
Most computer cables you can plug/unplug with wild abandon with no ill effects: serial, parallel, midi...
Parallel ports do not have any special protection built into them and are most definately not safe to plug/unplug while hot. PS/2 ports (keyboard and mouse) are also not safe. In the days of the 386 and 486 I knew a lot of people who damaged their keyboards and motherboards from doing this. These days the microcontrollers used are a bit more rugged, so the chance of damage is a lot less, but there's still no real protection built into the ports.

Serial and USB were designed to be hot swapped so they are safe. I don't know if Midi was designed to be hot swapped, but the protection built into it because of the isolation designed into it for noise reduction has the effect of making the ports pretty safe.
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  #5  
Old 10-27-2005, 12:00 PM
Una Persson Una Persson is offline
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*In theory* it's not recommended due to the possibility of static discharges, etc. In practice, there is no harm whatsoever in it, although like Nanoda said, you may, depending on your OS and situation, have to request an IP refresh. I have an NT machine that once you unplug the cable once will never find the network again, until you reboot, no matter what you try to do. XP is much better at that, although after a few hibernates and plug cycles, the behaviour becomes erratic.
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  #6  
Old 10-27-2005, 12:14 PM
633squadron 633squadron is offline
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Quote:
Originally Posted by engineer_comp_geek
Parallel ports do not have any special protection built into them and are most definately not safe to plug/unplug while hot. PS/2 ports (keyboard and mouse) are also not safe. In the days of the 386 and 486 I knew a lot of people who damaged their keyboards and motherboards from doing this. These days the microcontrollers used are a bit more rugged, so the chance of damage is a lot less, but there's still no real protection built into the ports.

Serial and USB were designed to be hot swapped so they are safe. I don't know if Midi was designed to be hot swapped, but the protection built into it because of the isolation designed into it for noise reduction has the effect of making the ports pretty safe.
I agree. I forgot to mention this. I've plugged and unplugged parallel ports before with no damage, but the protocol is not guaranteed to remain stable through it. Fortunately, parallel ports are obsolete.

I've also done PS/2 ports, and again while I didn't suffer damage, the protocol doesn't support it.

Dunno about MIDI.

Anyone know about Firewire? We should also solicit feedback on Serial ATA and SCSI.
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  #7  
Old 10-27-2005, 12:25 PM
MyNameIsEarl MyNameIsEarl is offline
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Quote:
Originally Posted by Nanoda
Sure, no problem. At worst you'll have to re-request an IP address when you plug the cable back in (Start -> Control Panel -> Network -> Right-click -> Repair in Windows XP).
No, no, no. That's all wrong. It's fairly rare, but having XP "repair" a connection that's just working fine can sometimes break things (I've seen it happen with wireless cards more often that wired ones). To request a new IP address, click Start > Run > cmd.exe > ipconfig /renew. Better yet, if you're on a home network, just use static IPs... it's not hard to keep up with 3 IPs for one house, plus you don't have to deal with DHCP.

Quote:
Originally Posted by Nanoda
Most computer cables you can plug/unplug with wild abandon with no ill effects: serial, parallel, midi... I suppose I'm not a fan of loud humming when messing with speaker cables, but that's never been a problem for me either.
This is completely wrong too. Significant amounts of electricity are involved with the parallel and PS/2 ports - I've seen more than one motherboard fried all to hell by someone plugging in a PS/2 device when the system was powered on; parallel devices not so much, but the threat is still there.
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  #8  
Old 10-27-2005, 12:26 PM
MyNameIsEarl MyNameIsEarl is offline
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D'oh! I forgot to mention that Firewire - like USB - is hot-swappable.
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  #9  
Old 10-27-2005, 01:33 PM
gotpasswords gotpasswords is offline
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With USB and FireWire devices, be sure to "stop" them first. It's very easy to corrupt a portable hard drive by unplugging it while data's being transferred, or if files are left open.

Even though it may not be safe to hot-plug a PS/2 mouse, I've often seen Windows say "I can't find a mouse, but it's safe to plug in a PS/2 mouse now" on startup if there's not a working mouse.

As for the Ethernet, no problem. Just be aware that any logged-in sessions (online banking, web-based email, etc) will be disrupted and will need to be re-started.

Why would you want to disconnect the Ethernet while the PC is on?
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  #10  
Old 10-27-2005, 01:52 PM
engineer_comp_geek engineer_comp_geek is online now
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Quote:
Originally Posted by gotpasswords
Even though it may not be safe to hot-plug a PS/2 mouse, I've often seen Windows say "I can't find a mouse, but it's safe to plug in a PS/2 mouse now" on startup if there's not a working mouse.
Read the error message more carefully. It says it can't find a serial or PS/2 mouse, but only says you may safely plug in a serial mouse at this time (or something to that effect). The message isn't worded very clearly, though, from what I recall.

Quote:
Originally Posted by gotpasswords
Why would you want to disconnect the Ethernet while the PC is on?
I do it all the time. I have a couple of computers which don't need internet access, so I keep them isolated off of my home network. When I want to transfer files to them, I put them on my network then remove them when I'm done.

My laptop is also usually disconnected from my home network when I'm using it at home, but also may be temporarily connected so I can transfer files to/from work.
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  #11  
Old 10-27-2005, 01:58 PM
KlondikeGeoff KlondikeGeoff is offline
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Quote:
Originally Posted by gotpasswords
Why would you want to disconnect the Ethernet while the PC is on?
For a pretty stupid reason. Only recently got boradband cable,and used a router (as well as ZoneAlarm) for firewall protection. I just got curious as to whether might get better speed if I bypassed the router.

Being lazy, just hoped could unplug the cable from the router and back into the modem and test speed both ways.

Guess will give it a try.
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  #12  
Old 10-27-2005, 02:32 PM
Nanoda Nanoda is offline
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Oh. Well in that case you're certain to have to repair the connection (never had a problem with that even when I was doing XP tech support, Earl). Even that's not guaranteed to work, as many ISPs only give you one IP address at a time, and it's bound to the MAC of the NIC that first requests it.

Normally you can just power cycle the modem and it'll let you have an address though.
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  #13  
Old 10-27-2005, 05:04 PM
guizot guizot is offline
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I admit to still having a PCMCIA SCSI card for my laptop. (Yes, it's that old.) I use it for a LaCie CD writer. At the time I got it, it was faster than USB I. It still works fine so why get a new one? Daisy-chaining is a pain in the ass, but it serves it's purpose. The only thing I have that isn't hot-swappable is an old external Zip-Plus drive, that I used to use in the daisy-chain, but now just use from the parallel drive for convenience.

It really depends on your OS. If you have XP, you don't even need to close anything.
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