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Tom's Hardware KVM Roundup
nexex writes: "Tom's Hardware has a new article with a review of several KVM switches. I have considering buying a KVM switch as I seem to collect/use more & more computers, I feel left with little choice :) While I have several friends who have taken the plunge, they have all spent wildly different amounts on them. Granted price plays a great factor on the features you get, but how do you know which one is not going to end up letting you down? If you end up with el cheapo, you will most certainly end up regretting it, as this device will be carrying the signals of your primary input and output to your systems."
If have nine machines - I have 1 spare monitor and keyboard for base boot and load. Once loaded VNC all the way - even with linux.
Nice to be able to use any machine any where in the house with touching it.
I bought a different Linksys KVM switch than the one on Tom's Hardware. I think its called the PS2KVMSK or something. It is much cheaper at about $50 dollars, including all the necessary cables. Ive found it to be a great value and is extremely convenient because it has keyboard-activated switching. The switch is signaled by two quick CTRL key presses. One thing to note though is that if you are playing games that use CTRL frequently, there seems to be a lag between the CTRL keypress and the action in the game. Other than that it performed flawlessly and was definitely worth the money.
Here's a less expensive solution.
It can't do everything (it irks me that I can't log onto my 2K box through it), but it also doesn't limit you to a few feet away.
I've been using the IOGear 2-port KVM switch reviewed in the article for several months now, and I have to say I love it. I use it to share between XP and Linux, and neither machine has ever had a problem with the USB devices. I did run into a slight problem with the video causing snow and jitters in X11 (no problems at all in XP), but adjusting the modeline (dumped via xvidtune, changed the polarity of the hsync) made the problems disappear. For anybody who wants to get away from PS/2 systems, or uses Macs, I really do recommend IOGear.
The only thing I could wish for is the OSD/hotkey support of IOGear's 4-port model, but I can live without that. Also, Tom's price was a bit high. I bought mine for roughly $100 at a local computer store.
You can see my setup right before they laid us all off. And of course they kept the KVM and the shiny laptop... :(
TO BUY A NEW CAR WOULD MAKE YOU SEXUALLY ATTRACTIVE.
My experience with workstation switches from several different
manufacturers is that they are very expensive (around $1200 for a quality 8 pt switch) and that they have siginificant maintenance issues.
Where I work, we use a couple dozen switches on many, many server machines, and are RMA'ing them all the time because they simply break down quickly. Mice are the first to go. Then monitors. Maybe we're just unlucky. Personally, I feel that if a piece of hardware is dipsosable, it should be given a disposable price.
We have to have these for space reasons, however, so we keep plugging away at trying to keep them working. Recently, we've been reducing the costs associated by picking up several nice switches from dot.bomb auctions. We're getting them from anywhere between 10 and 20%. For high-maintanence hardware, this is *much* better than paying full price.
The next Slashdot story will be ready soon, but subscribers can beat the rush and slashdot the links early!
The guys at Inova have a KVM switch not reviewed in this article. In addition, they claim that it doesn't just switch the KeyboardVideoMouse, but all your silly devices. There's a small, pleased review of it here.
bug.gd: error search engine. Humanity working together to solve all errors.
Why would there have to be ghosting at 1600x1200? Is it not possible that all those units were capable of supporting 1600x1200 and higher without any problems? I currently use one of the switches in the article, and use Cybex and Belkin switches at work all the time, and I run in 1600x1200 on nearly every machine I use. I've never had any ghosting problems from quality switches. Perhaps it could've been mentioned that there were no visual problems, but how interesting is that when that's the expected case?
I use 8-port Apex KVM switches at work, and they have some nice features; they also have a few flaws. These KVM switches arent the cheap ones found in this review, but if your looking for higher end equipment I might be able to give some useful nformation.
The switches are only KVM, no sound, no USB. To change screens, you press the print screen key. It brings up a menu, and you can choose between any of your machines. The machines can all be named, so you know exactly what machine you are going to. Another nice feature is that you can chain them together for more than just 8 machines on the switch. My only real complaint is that sometimes the menu doesnt get erased when you switch machines, so you have to bring it up again and get rid of it. I havent had any problems with screen resolutions, keyboards or mice. Definitely worth looking into for a setup with more machines than two.
I'm surprised Tom is so exciting about audio switching. Most decent speaker setups will take more than 1 input signal, so you can have both (or more) boxes hooked up to the same speaker at once all the time. It's nice to be able to play a CD or something from my other box while I'm using the first's drive.
PS: What's a formkey? I finally got one of those weird formkey errors that I've been hearing people talk about.
--
Runnin' around, robbin' banks all whacked on the Scooby Snacks...
If you are interested in sharing a single set of keyboard and mouse (but not the display) between 2 computers, check out x2x.
:)
Some karma whore can post the link to it
I've been using a Belkin OmniCube 4-port kvm at my desk for almost a year now and it's been great. I think I paid about $130 for it, but I've recently seen it for nearly half that on sale at the various superstores. I have also chained an older Belkin OmniView 2-port kvm off it and it works fine.
KVMs are no longer just the domain of the NOC... for those who prefer Linux, but need a Win2k or 98 (ugh) box on demand (or anything else for that matter) a kvm can be a huge plus. It's also allowed me to save space (got rid of 2 extra monitors on my other desk).
The OmniCube has a nice shortcut... double-tap scroll-lock, then hit the number of the box I want and it comes up. This has allowed me to leave the kvm on the floor behind my desk, with all the cables.
One thing to consider... I use a high resolution and a high refresh rate on my monitor... if you want 1024x786 @75Hz or higher, you'll probably have to shell out around $25 for a high-end vga extension cable. PS/2 extensions can be had for under $5 ea, and lower-grade vga extensions are easy to find under $10. Just something to keep in mind if you are on a budget.
Only negative I've found is that I need to have the Win2k box selected while it boots, otherwise the wheel mouse isn't detected... the rest of the mouse works, just not the wheel.
Anyone know if it's possible to get my Sun Type 6 USB keyboard to work on my old intel PS2 system, through a switch? Is there a USB->PS2 converter that works with the Type 6, that I could connect on the switch output to that PC? Any ideas if I would run into problems switching between them, and losing keyboard? Same question regarding Sun's Crossbow USB mouse. I really wouldn't mind all that extra desk space.
I had a Belkin 2-port for a long time that worked nearly flawlessly. The only problem I ever had with it was switching away from an X session and then going back would cause the mouse to go haywire to the point of needing to restart X. Not sure if this was the fault of X or the KVM switch, but either way it was annoying. :-)
A few months back I was looking through uBid.com and found a 4-port KVM that had plenty of features (more than the Belkin, at least) and even included 2 free cable sets. I had never heard of the brand (Genie), but I figured at only $100, it was worth a shot to get all my machines hooked up to the KVM and thus ditch an extra monitor. And luckily enough, it has performed flawlessly. It still irks me to remember how much I paid for the original 2 port Belkin (almost $300 a couple years ago) now that this "cheapo" one is working so well, but its also good to see the good features and stability of the higher end KVMs coming to the lower end of the price range.
Perl - $Just @when->$you ${thought} s/yn/tax/ &couldn\'t %get $worse;
Background: Good KVM's are expensive. Cheap KVM's are awful. Many monitors now have a built-in high quality A/B switch. Many KVM users spend 95% of time on a workstation, and occasionally have to flip to a "headless" box to make a BIOS change or something.
Why not buy a cheap KVM, attach a cheap keyboard to it, and plug it into input B on the monitor? Then most of the time you have high quality video from the workstation to input A. When using the KVM, you probably don't care about quality. Of course, there is the danger of typing on the wrong keyboard.
Personally, I just use the monitor A/B both at home and at work. The B cable goes on whatever box I'm fixing/setting up at the moment. Once the box has networking, there is no need for KVM.
I have an OmniCube (2-port; no USB) and I love it. Once in a while I get a blank monitor after hitting the scroll lock key twice and the up/down arrow key to switch to the other computer. I noticed my monitor (IBM P72 17") says it lost the video signal. I have to turn the monitor off and then on to make it come back.
:)
My Red Hat Linux 7.1 box is a Pentium II 300 Mhz with a Matrox G400. My gaming/Windows 98 box is a Pentium III 600 Mhz with a Leadtek GeForce2 Pro (64 MB).
Is anyone else experiencing this problem or know if this a known issue? Thanks in advance for a reply.
Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
The review doesn't say whether the Belkin KVM (which otherwise seems really nice) takes USB mice and keyboards for input (it does generate USB mice and keyboard outputs). Does anybody know?
Some time ago, I was looking for a solution to a cross-platform KVM integration issue, tying some SGI gear and my PC to a single console.
My problem arose because the SGIs use a sync-on-green signal through 13w3 plugs, while PCs typically don't. I was lucky in that most SGI kit made in the mid-90s and after uses PS/2 mice and keyboards. I further complicated my situation by wanting to tie the sound from the different boxes together.
Eventually, I bought a Belkin OmniView SE 4-port PS2 KVM switch, and some adapters. To handle the sound, I bought a cheap Fostex digital mixer from musiciansfriend.com[1], wired it all up, and today, I am the proud owner of a monstrous rat's nest of cables and boxes that pipe sound from multiple machines into one set of speakers.
It would have been a hell of a lot easier and cheaper just to buy three sets of speakers. I'd be careful when evaluating a KVM+Sound switch, verifying that sound is mixed from all channels, as it is almost a necessity to be able to hear output from a non-focused computer.
As it is, I'm ecstatic about the Belkin gear. I have the OmniView SE here at home, and the OmniCube at work, and with decent cables, I can drive the monitors at 1900x1200 without any difficulty. I found this to be just about the most important piece of the kit -- with cheap cables (the kind you can buy for $10), the video starts bleeding and exhibiting static above VGA resolution. Don't waste your time with the cheap cables, spend the extra $10 or so and get the decent ones.
[1]: I am intentionally not making that a link because the bastards are almost as bad as x10 for daily emails once they have your address.
Before you yell out VNC, follow me...
Wouldn't it be nice if you had a box you could tack onto your existing system to pump the basic IO over your existing CAT-5 wiring? My ideal unit would have the following
Input jumper for power switch control
Input jumper for reset button control
Light sensor for power light
Light sensor for HDD light
Light sensor for Link light
Light sensor for Act light
Serial PS/2 port for keyboard
Serial PS/2 port for mouse
15-pin RGB port for monitor
Here's how it would work. You mount the box on the back of your server unit and connect your power and reset buttons to the unit and connect the unit to the reset/power jumpers on the motherboard. You stick the light sensors near the respective LEDs. You wire up the KVM to the unit and optionally plug the local devices into the unit.
Now, the unit is a little linux box that takes the input and sends it over the network (now we're using VNC) to my remote session. The bonus is that I can still see the unit if it's crashed (the VNC service or the whole dang box). I can boot into the BIOS and make changes. I can run utilites and so on from DOS sessions. Plus, I can click a button and reset the box, or power it down. If I connect to the session and see no image, I can see if the power light is on or if there is any hard drive/network activity.
I can think of about a billion times in my techie lifespan that I've wished for such a device. Yes, I know there devices you can use to remotely power off a computer. Yes, I know I could setup a webcam to monitor some lights. Yes, I know VNC gets me most of the way there.
But it's not cost effective to buy one of these for each server. I would rather have one box that could control 4/8/16 boxes. It's just a standard KVM with some extra inputs attached to its own dedicated Linux box!
So please, Linksys, Belkin...whoever...can't someone please build this, or show me a link to something like this?
- JoeShmoe
-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
Oh, by the way, how about this quote from the article--"I could go into a long winded explanation of how KVM switches work, but, to be honest, I found this to be boring, and I am sure that most of you would, too, so I will spare you the explanation." If he really could do that, why can't he go into a concise but complete explanation?
I see even classic Slashdot is now pretty much unusable on dial up anymore.
I've been using a KVM for years, starting with a small cheap box that just switched the monitor signal to finally graduating to the linksys ProConnect 2-port switch.
.oops).
I don't profess to be an expert on KVM switches, but the Linksys has worked decently for me. It has this feature where it listens in on your keystrokes and switches computers at a double tap of the cntrl key. Annoyed the hell out of me in quake until I figured out what was going on (like most computer students I chucked the manual the instant it came. .
However, despite this, its VERY small, cheap (check it out here, comes with cables), and I'd buy another one in a minute.
-S
- - - - - - - -
Don't worry, being eaten by a crocodile is just like going to sleep in a giant blender.
In the article, Tom has concentrated on go/no-go tests. ... produced a good picture " (with no mention of the resolution tested) in case of the CS-USB21H , or no mention of picture quality at all in case of the GCS124U KVM .
In a product that can influence picture quality tremendously, I would have liked to see something more than "It
It would have been really helpful to see characteristics like 'amount of reflections' or 'actual measured bandwidth'
This would have helped me more on deciding which unit is right for my purposes than describing the computer systems that were used in detail. What is the use of specifying the brand of CD-writer or the amount and brand of RAM that were used? I cannot imagine that these have any influence on the performance of the KVM switch.
At home I used a Iogear $60 USB KVM that works really well for video but causes all sorts of problems with the USB keyboard setup under Linux on my Tiger 133a (There is a problem with linux on the via chipsets that cause it to not be able to use USB devices with SMP enabled)
At work we use Aten Masterview switches wich cause all sorts of problems. They meerly move the monitor, keyboard and mouse connectors through solid state switches. This is anoying because when a system reboots you get keyboard errors and things like that. (Yes, I know most BIOS's can disable these warnings.. but nto all of them =) We are slowly switching over to the Cybex A400 series KVM's. These switch boxes allow us to connect up to 48 computers into a single monitor/keyboard. (several 4 ports into a 16 port) They include on screen display and lots of other features. One really nice thing is that they only use a cat five cable between the switches and not normal keyboard/mouse/vga cables.
The major draw back to these switches is that they cost a LOT. (up to $20k for 48 systems) They do however display really well and flow the keyboard and mouse across all systems. They also can be setup to give users access to some systems but not all. So you could give your user the ability to access the workstation/test system next to the server but not the server itsself. Its really nifty =)
(And of course, this review comes our TWO days AFTER I purchase a new Belkin 4 port E-Series switch box =) The thing hasn't even gotten here yet!
I have a 2-port Belkin OmniCube and a 4-port Raritan SwitchMan.
The Belkin OmniCube is crappy, doesn't support high resolutions and decent refresh rates, and then it broke so that I could only get signal to one of the computers. Yay! A signal degrader instead of a KVM. The place I work at also has larger Belkin KVMs and they're not working like they're supposed to. Cheap and a waste of money.
The Raritan SwitchMan is exceptional, and works wonderfully. However, you need to use special cables as it wants Male to Male instead of the usual Male to Female. The cables aren't cheap. But I can run high resolutions at 85Hz, and there are some programmable features. You can also chain them together. The more expensive Raritan models support some even more interesting features. The only drawbacks are the somewhat more expensive price, and lack of support for Macs and USB.
I've also found that in addition to switching the keyboard, monitor, and mouse, I want to switch the audio. So, I purchased a Nady MM4 mixer from Musician's Friend (about $80 after shipping) and now I can also mix four audio sources to my Desktop Theater 5.1 sound system.
Something else I think should be mentioned is that you don't have to use KVMs (or the audio mixer) only for computers. I have my Dreamcast plugged into the Raritan KVM and Nady MM4 mixer for use with the VGA output. I plan on getting a PS2 and sending it to the same port of the KVM via a breakout box and video switcher (and my N64 at that point as well), or to a TV tuner card and then to the monitor, plus it's audio signal to the mixer.
The only thing I really want but haven't seen anywhere is the ability to use Macs and PCs alongside the gaming consoles. You can't really interchange Mac and Windows keyboards, but I'd love a KVM that I could do that with. If it could just interpret the Command/Apple key on the keyboard as the Windows key, and vice-versa, then I could put them all on one keyboard, monitor, and mouse.
I've been using Cybex stuff for a couple years now, I have one at home, one at work and 2 in my sever room. They work flawlessly and the 2 port Switchview with cables is $169.
About the Blekins, the reviewers didn't have any trouble with them and I see positive comments as here as well but IMO, they suck really bad. I had one at home that was junk. The last company I worked for had one for every developer and ended up replacing all of them, they were just terrible.
Needing to multiplex a console between two machines is somewhat silly. I got into KVM tech when 8-16 machines were involved. My company use Sybex 8 port units and they worked well. You could even slave the units to handle more servers. At home, I have a bunch of PCs (4-8) so I took the plunge with a 4 port OmniView unit (1998). That broke within 18 months. I then replaced it with a 4 port Linksys unit and that seems to be working very well. WinME can see my wheel mouse and linux can see that I have some kind of two button thing. No complains.
The warning about cable management should be taken to heart. I'm nearly drowning in the buggers. I suggest getting a metal rack for storing your PCs, printers, scanners, KVM unit. Use zip-ties or velcro strips to secure the cabling. It's worth the investment. When the cables were loose, my cat starting *eating* through them. That's a different rant...
As for mulitplexing sound, get an audio mixer. I have a Mackie 1402 and love it. My speakers (Labtec Edge 418) are plugged into the mixer, as are the PCs. I can even have my tape deck hanging off the mixer. This mixer/PC system has replaced my stereo.
One last point: I don't have a TV either, just a tv tuner card. Single appliance convergence? Already there!
Get x2vnc it lets you move the mouse and keyboard between monitors by moving it off the side of the screen. Works great except that the mouse wheel scrolls in the wrong direction under windoze.
The difference between Canada and the USA is that in Canada healthcare is a right and gun ownership is a privilege.
The reviewed KVM switches seem to be doing too much work. Maximum video resolution? Firmware upgrade? Hah!
:)
My KV (no M, they were out of ones with mouse ports when I bought it so I have 2 mice) is an extrememly simple switch that basically looks like the printer switches you can get at Best Buy. It has 5 VGA and 5 PS/2 ports on the back (one pair goes to the monitor and keyboard, the other pairs go to computers) and a toggle switch on the front. I simply move the switch to whatever computer I want and the signals go through. I don't think I paid more than $20 for the thing, and it's been working for more than 2 years. I don't know much about the brand; I bought it at a small computer show. It says it's a QVS Heavy Duty Dataswitch. Since I've never really had any problems with the switch, I haven't cared all that much.
My biggest problem is the fact that I can't seem to find any decent video cables, so I get a subtle shadowing effect at high resolutions. It's bad at first, but I've learned to live with it. I suspect that if I got better cables, it would go away, but everywhere I look that even bothers to sell male to male video cables sells the same type of crappy looking ones that I have.
I've looked at some of the more expensive switches, and I really couldn't justify spending that much, especially when my little switch does everything I need. And having two mice really confuses other people when they try to use my computers
"Save the whales, feed the hungry, free the mallocs" -- author unknown
No people, VNC is not a magical kvm that replaces the need for KVMs. Nor can it be used as one. It's more of a hack around using kvms, or for those who can't afford actual KVMs (which is not something to be sneered at - KVMs are really expensive).
1) If networking dies, VNC dies.
2) If something in the operating system goes really funky, you might not be able to VNC into it.
3) Additional system overhead.
4) If the system hard crashes, you can't see what the last error message says. Even linux and solaris boxes panic.
5) Saying that everything should be managed from a serial port is misguided. A GUI shouldn't be so dismissed, there are lots of WinNT servers out there with is mostly graphical driven, and there are X apps and the Netware console screen that you can't see through a serial port. Likewise, what about a whole bunch of workstations, probes, monitoring machines, and other commodity x86 hardware?
6) You can't see POST and OS loading messages with VNC.
VNC is okay if you don't have any cash, or perhaps in your house. It's not the greatest solution in the world, and can't replace the need for a KVM. I wouldn't advocate using it as a kvm in a machine room.
A little over a year ago I bought a Dr. Bott 2-port USB KVM from DevDepot for $139. Dr. Bott stuff is more Mac-friendly than most-- the KVM has dual video ports (i.e. Mac DB15 and PC HD15) for each position on the switch.
All cables are included with the switch, and the video cables have one end HD15 and one end DB15-- no matter how you have to hook your computers up, you can get it done by just swapping cable ends, no video adapters needed.
Contrast this with Belkin, who charges out the ass for everything, cables are extra, and sometimes requires a separate box to provide Mac connectivity, resulting in an ugly mess of tangled cables. Sure, the Belkins are electronic while the Dr. Bott is physical, but I'd rather pay less and wait a few seconds for my keyboard and mouse to be detected when I switch (and have a much neater-looking work area).
until you have to replace hardware in one of those, and then you will have to move junk around (keyboard and monitor, or the system itself) when you bring it back up (ie, having to change the bios settings if you add a drive).
I just went through this with my headless firewall. I sure wish I had a KVM for the machines then. Then again, that's about the only time I would ever use it, so I guess it would be wasted money for a little bit of annoyance.
I meant to add that I've got this Moniswitch2 USB setup working with a Power Mac 7600 with a USB upgrade card in it, and a home-built PC running Win2000.
The KVM also switches back and forth flawlessly when I've got my other HD module in the PC and it's running Red Hat 7.
~Philly
That doesn't work when you have to reboot and make a bios change. I can do all of that stuff using X11 forwarding, and it works better. You probably don't want to play games like half-life that way either(I don't use everybody's quake example..because THAT RUNS NATIVE ON LINUX, YOU FOOLS!)
If you use the cheap cables that came with some (a Belkin in my case) of the KVM's, you get ghosting. I run my boxes at 1600x1200 and had ghosting problems until I picked up some nice shielded video cables.
+++ UGUCAUCGUAUUUCU
I had one demo'd here at work. It was being resold by WrightLine, the rack enclosure people, but was available seperately from the manufacturer.
It was tres expensive, though -- like thousands of dollars, *but* with the client you could connect to any machine that was connected to it over a network and get hardware-level control over the machine -- BIOS screen, dos prompts, totally seperate from the OS running on the machine.
The magic was their ability to do real-time video compression of the hardwired systems displays. The client app that could connect to the switch could also resample a hi-res screen to fit a lower res screen, as well as send special keystrokes so that you could use cheapie switches daisychained off of the expensive one.
It had limitations, though -- the client software was licensed (cheap money grab attempt), and it was a bandwidth pig. The guy that demo'd it didn't think it would be practical to control a system via dual-channel ISDN and barely practical over broadband connection. And it was REALLY expensive, I seem to remember a price in the thousands for the 8 port box, cables and a 4 client license of the remote-use software.
What surprises me is how dumb the video is in even non-networked high end KVMs. Why isn't there an option to do picture-in-picture? Or tiling all connected systems on one screen? With a good hi-res display and resampling, you should be able to monitor (maybe not use 6pt windows, tho) multiple systems at one time. There's loads of video tricks that get used in even the low-end TV world that really ought to be in the KVM world.
I just bought a Belkin 4-Port KVM switch a while back for $100. There is a huge, huge difference in prices between stores. My local Fry's and Micro Age carried the same one for around $270. After cruising Pricewatch I bought mine at Harmony Computers. Gotta love the Internet.
JOhn
Campaign for Liberty
My wife taught me a great phrase: "you don't ask, you don't get". While employed in a server environment, we were updating all the Cybex switches to the latest and greatest model. I asked if I could take one of the old ones home, the boss said "sure." I draped sixteen 10-foot cable sets over my shoulders and carried the two control boxes right on the train that very night. You just have to ignore the funny stares :)
When the company was throwing out some old Digital DECTalk hardware, they offered it to me "only if [you] can take it home tonight." I replied, "it's a good thing I drove!" I got a 5 foot rack with four 8-channel DECtalkers designed to convert serial text into speech audio out over phone lines and return DTMF keypresses back to the server over the same serial lines. I gave away 3 of the 4 talkers, kept the 5 foot rack and two serial sprayers. I thought it would be perfect for 8 channels of hardware text-to-speech in my home automation setup. (Its the same hardware used at NOAA weather radio.) Too bad the terminal server talks LAT. Linux will support it soon enough, if it doesn't already.
A friend recently went through a big cleaning in his server environment and made off with two active KVM switches. His are better because my passive ones don't support higher than 60Hz refresh. Mine are just fine for Linux consoles and VERY light duty X work.
Finally, during a really big spring cleaning, I brought home a Digiboard PC/8. I just need a reason to buy the 8-way octopus cable for it.
So for the cost of the Digi octopus cable, I can console-switch among 24 machines on 2 consoles, and hit 24 to 72 serial ports if you count those on the console-switched servers. Oh, I also have two 96GB 12-tape changers, a 48GB 6-tape HP changer, and a 40GB Exabyte Mammoth, but that's for a different "Ask Slashdot".
I have to say, there are times where I absolutely have needed KVM access to the Linux servers. I haven't setup any serial stuff yet, and my Amanda tape backup sometimes freaks out. I put SSHD as a respawn in inittab, but when a rogue app has exhausted all your memory and swap, direct console access via KVM (or I'm sure serial, too) is all you have. VNC wont do crap for you. And for hardcore firewall tweakers, we can all tell you we've locked ourselves completely out of the firewall at one time or another. I recently locked myself out of a remote box because when I upgraded SSH, I forgot to reset it to the non-standard port I listen on before I HUPped it. I loosened the firewall to listen on 22 just in case I pull that one again!
Intelligent Life on Earth
We actually use a serial console system for most of the ~200 servers in our machine room (we have an actual monitor/keyboard/mouse on a little cart we wheel around for when we need it, which is rarely).
Anyway, to the point, you can make a simple little loopback plug for the keyboard and/or mouse if the system is fussy about that sort of thing.
Shut up, be happy. The conveniences you demanded are now mandatory. -- Jello Biafra
Do not meddle in the affairs of mice, for they are subtle and quick to anger.
No really, it could have been the mouse was "detecting" the wrong mode. I'm not sure exactly how those ps2/serial combo mice tell which protocol to use, but it could either be a connection in the adapter that is made (similar to a jumper), or something sent on bootup. Either that or I am totally off-base, but that seems like a likely explanation.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Okay I assume most of you here either a) have a KVM and either like or hate it, or b) don't have a KVM but might consider buying one but don't know which to buy. I'm going to tell you what you should look for. And by the way, Tom's guide (as usual) is dreadfully incomplete.
Some switches are mechanical, and others are electronic. Most electronic ones are better because they feature some kind of "emulation", meaning that when you switch off one machien to another, the machine you switched FROM still thinks the mouse and keyboard are connected when the OS polls the ports. On mechanical KVMs, they won't see anything and will sometimes b0rk.
However, not all emulating electronic KVMs are created equal. Belkin, Aten, Linkysys... they all have the same fundamental flaw: they have only one microprocessor trying to handle the emulation requirements of all the ports on the KVM.
One of the best switches you can possibly buy is a Raritan. They have a dedicated microprocessor for each port.
I have tried using a Belkin Omnicube and an Aten Masterview with a very simple setup: one Windows XP box, and one FreeBSD or Linux box. With both switches, XP worked fine but with FreeBSD, you get (at best) errors from the kernel about how the mouse is out of sync (psmintr....). With Linux, I could only get it to work if I used a standard PS/2 Microsoft Intellimouse with the gpm and X driver settings set to "PS/2". If I wanted to use "IMPS/2", I had to kill and restart GPM every time I switched back to Linux. And neither Linux nor FreeBSD would even RECOGNIZE my Microsoft Optical Intellimouse with the USB-to-PS/2 converter on the end... although I reiterate that XP worked just fine.
Raritans, on the other hand, work flawlessly in any situation. They JUST WORK. I'm currently waiting for my new Raritan to arrive in the mail. They're slightly more expensive, but totally worth the money. And for those of you who are sysadmins for larger-scale projects, consider Raritans for those racks because they make rack-mountable KVMs with up to 12 ports... we used them at Internet2 and they work perfectly.
peace brothas.
Intercarve Networks, LLC
Compaq's line of KVMs are rather nice for server managment, but come at a price. They have one that is a 2x8 KVM, aka 2 consoles and 8 ports. This is ideal for having one console in the server room, and one console in your office. And you can chain a KVM to each port, thus a total of 64 servers from one place.
Their newest idea is to use PCI cards and CAT5 to chain the systems togther. It uses the PCI power, and since the KVM is inside the server, it can save quite a bit of space and cable mess. And yes, they do pass through when the server is powered off.
Not the rolls royce of brands, nothing outside of "K-V-M" is switched BUT the unit (and the cables) produced no ghosting, it works be either pressing the putton on the front of doubletapping scroll lock and then the number of the terminal to switch to. It's also not terribly expensive.
Jon - TheSpork
I decided I needed a 4 port, and decided not to go with the Belkin next up unit (for price as well as the problems with the 2 port). Browsing Fry's, I found a LinkSys 4 port self-powered (from keyboard power, and since one of my machines is never off except in a power outage, it stays on all the time) that had a good price (under or close to $200, and this was somewhere around or over a year ago) that works great.
It does have the cabling mess drawback; it's kind of flat lozenge shaped and has 2 system port sets on each side and the master ports out the back. But I haven't had any serious problems with it (any time I've gotten "no keyboard" it's been when I've switched right at the wrong moment in a boot). And it supports keyboard shortcuts to switch, so I don't even have to reach up to hit the button (maybe that's common now, but I was tired of whacking the button on the Belkin, and I'd only see this feature on "serious" kvm managers in data centers prior to getting this unit).
It's the "4 port compact KVM switch" and I'd recommend it pretty strongly.
7 November 2006: The day Americans realized corruption and incompetence weren't addressing 11 September 2001
Currently I use the IOGEAR GCS124U - MiniView USB II - 4 Port USB KVM Switch (Hotkeys/OSD). For some reason when I'm in Mac OS 9 or KDE the scroll wheel is not detected. When I contacted IOGEAR support they told me it was a known issue that would be taken care of via a free chipset upgrade I could send the unit in for. The new chipset has been held up because of the terrorist attack and typhoons overseas. I highly recommend this unit but you may wish to check to make sure you're getting the latest revision. Strangely, Mac OS X does detect the scroll wheel just fine.
Stay away from it if your run Linux.
1) The keyboard switching doesn't work at all.
2) The keyboard repeat rate is LOCKED at 10.2 CPS under Linux. You cannot change the keyboard repeat rate with Linux at all.
3) The technical support people NEVER returned any of my calls of e-mails. They didn't help me at all.
Their switch is broken, and they don't give a shit that I had problems with it.
If tits were wings it'd be flying around.
Production environment? No wonder why you posted as a coward...
"I'll just chip in a bit for RedHat: I actually have that installed on my university machine." - Linus, '95
And haven't regretted it since!
I used to use one of those mechanical four port kvm switches - but after a while (a couple of years) it started to get very flakey on me, so I decided to get something a little better. I wanted an active switch, but I needed at least four ports, hopefully more - but everywhere I turned, the price was INSANE for anything over two ports...
Then I decided to try Ebay...
I ended up bidding on an ATEN CS-106 from a seller on Ebay, who had a few up for grabs as used equipment. I bid - and someone out-bid me. I was crushed, because my bid was $50.00, the person who had sniped me was $51.00. I noticed he had a zero rating, so I emailed the seller, and let him know that I was willing to pay was the winning bidder offered if he didn't come through (I had a rating of 40). The seller emailed me back, and said that he thought he had an extra, sans a power supply, and sold it to me - I sent him the money via paypal, and before he sent it, he said he found the PS and would throw it into the deal.
About a week later my KVM arrived - only a slight dent on the case gave any indication that it was used - other than that it was in perfect shape (even had the manual!). It was AT only (serial mouse, etc) - but for my needs perfect - 6 ports of perfection, for $50.00!!! I plugged it in using the cables I had already, and everything has worked great since. A simple CTRL-ALT-SHIFT-port#-RETURN to switch ports, other key combos to page through, or you can use the front panel switch. The case is built like a rock (pretty heavy steel construction).
I can only recommend this KVM - unless you have a need for a more expensive remote capable (ya know the kind, with Cat5 between the master unit and the remote), this one is it.
Oh, BTW - I should say that I got lucky - if you note from the link above, it still retails (MSRP) for $300.00, I have seen it used for about $200.00, maybe a little less. I got lucky for $50.00 - not sure how (of course, I also have this print buffer/10BaseT printer interface that normally goes for $400.00, picked it up used for $5.00 at a local electronics dump - so, maybe I have a knack for these deals...hmmm).
Reason is the Path to God - Anon
/.
I also use this model and am reasonably happy with it. I use a generic AT keyboard and a single 3-button logitech mouse to drive a dual-boot win98/RedHat 7 box on port one, a RedHat 6.2 box on two, a 486-based dual-boot Freesco/Smootwall router PC on 3, and the fourth port is connected to an extremely long custom cable that I use for beowulf nodes and boxes ripped apart on the workbench as necessary. I used to use a MS "Natural" keyboard on the Belkin until I spilled something nasty in it, and that worked OK too.
HERE'S THE PROBLEM: You must follow this procedure when you set this thing up, or you will get the symptoms you describe.
1) Plug all cables into Belkin.
2) Apply power to Belkin.
3) Boot machines in any order *** BUT *** do not *** EVER *** switch consoles if any machine has not finished its boot sequence!!!!
4) You may now switch freely, and you may turn machines on and off as you wish as long as you remember never to switch while any machine is booting up.
5) Go forth and prosper.
This little gotcha really bothered me because I am the type of dummy who "saves time" by booting everything at once and switching about during the boots to spot-check for clean startup message sequences. You don't want to know how much time this "time saving" habit cost me before I got around to reading the damn manual.
--Charlie
/. :^( and have little time :^( so I just switch the video and shove the mac KB and mouse off to the side most of the time.
The problem with a mac is the weird keyboard (Apple Desktop Bus I think it is) and mouse interface my macs use. I can adapt the video to VGA easily with a cheap little adaptor, but the ADB to PC interface is blindingly expensive even though there are chipsets available fairly cheap.
I keep intending to build one myself from the chips, but I am way out of practice at that sort of thing
If anyone runs across a cheap solution to this problem PULEEZE post.
--Charlie