USB KVMs Compared 199
EconolineCrush writes "KVM switches have always been a great way to control multiple machines, and now they're coming with all sorts of cool USB peripheral sharing and audio switching functionality. The Tech Report has a compared a couple of the newest KVM switches from Belkin and IOGear that're worth a look if VNC just doesn't do it for you."
PS/2 KVM switches (Score:2, Insightful)
Re:PS/2 KVM switches (Score:2, Informative)
In fact, the only problem I've ever had with it is when my 6-year-old AlphaServer refused to recognise my keyboard when connected to the switch, but all the other hardware I've tried with it (including an Alpha Miata workstation) have worked fine.
Re:PS/2 KVM switches (Score:4, Informative)
Also, while VNC (slow screen updates), is by far the greatest free tool of it's kind I have ever seen, there are cases where you really really want to be at the console, and yet still keep your boxes in a controled environment.
Just one question (Score:1, Troll)
Re:Just one question (Score:2)
If you wanted to have a floppy/cdrom/etc, then you could place a small case with no fans. Your workstation would only hold a floppy, a cd or cd-rw, maybe some USB/Serial/LPT ports, or what ever you wanted, and boot it over the network. The power supply wouldn't heat up with out a fan because you wouldn't be running any hard drives from it, and your motherboard doesn't have to run a fast chip 486 DX w/o fan would do. This would allow you to have a super quite work env, and still have the benefit of "external media" next to your station.
I hope this answers your questions. If you are a troll, maybe someone else will benefit from this.
Re:Just one question (Score:2)
Obviously it's a bit drastic to place it in another house, but how far away from the host computer can you place something like a USB2.0 or FireWire device? 10 meters? 20?
_I_ honestly don't care about floppy, I just mentioned disks because maybe someone else would want to know.
Re:PS/2 KVM switches (Score:1)
Re:PS/2 ports... WHY?? (Score:3, Interesting)
My question is: WHY did everyone switch to PS/2 in the first place? The old RS-232(?) ports could be hot-swapped at will. What POSSIBLE benefit could there be in switching to a protocol that requires a reboot to "re-capture" the input device if the connection is lost?
I've been wondering about this for years, and never heard a satisfactory answer. Anyone know?
--jrd
Re:PS/2 ports... WHY?? (Score:4, Informative)
It was cheap when cheap mattered, and it replaced a connection without changing the way it worked. And for the record, the old connections were not RS-232 ports, so the question is a bit off the mark. Yes, they had some RS-232 components, but they weren't full-featured.
If memory serves, IBM invented this cable format for the PS/2. (You do remember IBM had a computer called the PS/2, right?) This particular connector might have been adapted from something else (strong resemblance to a Mac kbd/mouse connector, as I recall), but the big public play was with the PS/2. It was smaller, cheaper, etc, than the AT keyboard connector, and therefore a win all around. IBM then quickly adapted it for use with their `standard' PCs, and everybody followed. (Again, this was back in the days when IBM did something and everybody followed.) It was (and is) signal-compatible with the old keyboard, and I've still got a few of those ATPS2 keyboard adapters around somewhere in the dungeon.
At the time the AT-style keyboard connector was put on PCs (early 1980s), nobody ever dreamed we'd be having roomfuls of these things all cabled up to a single monitor/keyboard/mouse. The computers were too expensive for a person to own more than one, and not powerful or reliable enough to put into racks and stacks to provide specialized services. The kind of switching talked about here just wasn't envisioned, and in fact, would have been considered insane. Putting more expense into the component so it could be hot-swapped (and making the appropriate O/S changes) was simply not worth doing.
But eventually technology catches up, and the marriage of USB with keyboard/mouse permits the right thing to happen. One could argue that you ought to simply be able to plug/unplug the keyboard from USB host to USB host, and in fact, you can do that with some of them. But that still doesn't solve your monitor connection problems, and last time I checked, SVGA didn't work over USB. So a single switch that moves 3 components simultaneously is a big win.
I looked over the article posted at the top, and am pretty impressed. USB KVM switches are a great idea, and after reading over the above articles, I want one. In fact, I want both of 'em, because each has some very cool features.
Hmmm... so I guess I'll wait until the next generation comes out, when each company adds features from the other. :-)
Re:PS/2 KVM switches (Score:2)
I only have the mouse problems with optical mice. I haven't tested all optical mice, but all mine are those microsoft intellimouse jobs that are really USB mice with a USB->PS/2 converter. Every single one of them has issues with the KVM switch.
If I use an old straight PS/2 intellimouse with a ball, I have no problems what so ever.
Also, I can get the mouse back in Linux, but you may not like the method: If I do a ctrl-alt-backspace (the X windows reset), the mouse will come back but everything that was open will close (in fact I'll have to re-login).
This problem really displayed how weak KDE/Gnome was with non-mouse support (using keyboard only). At least back in 2.0. I ultimately gave up and installed Exceed on a windows machine. Now the KVM gets no use.
YMMV, Hope this helps.
USB? What about the UXGA? (Score:2, Insightful)
Re:USB? What about the UXGA? (Score:2, Insightful)
Try buying a quality KVM? I don't know about on LCD monitors (I haven't found a good-sized UXGA monitor in a comfortable price range for me, yet), but my 2pt IOGear USB KVM does 1600x1200 just fine on my 19" monitor, and the Cybex I use at work (not USB, unfortunately) does just as well on the 21" I have at work. Sure, if you're using a 5 year old KVM, you're probably not going to get very good video (unless you paid a lot of money 5 years ago). These days, you got ripped off if your KVM can't handle that.
Then again, things may be different when outputting on an LCD monitor (and I haven't seen any DVI-capable KVMs yet, so you can't mux the digital signal anyway, for the hihger-end LCDs).
Re:USB? What about the UXGA? (Score:4, Insightful)
Perhaps a read of the article is needed?
andquote :
Not designed to work with LCD screens (Score:5, Informative)
I tried the previous Belkin USB KVM. It sucked. Apart from failing to switch smoothly at all - the keyboard would constantly disappear on switching and then I'd have to actually move it to another port to get it to work - the video signal was terrible. I was running at 1024x768@70Hz. It was blurry as hell.
I contacted Belkin to tell them it was the least impressive product I'd ever bought, detailing my problems.
On the monitor front, they replied that the switch was not designed to be used with LCD screens, which was why the quality was so bad.
Seriously, when you're used to pin sharp LCD displays, putting them through a KVM and turning them into something that looks like a 6 year old CRT is not such a great idea.
Maybe Belkin have fixed this issue with the new one, but bear it in mind if you have an LCD screen.
I actually have two monitors and one kbd/mouse, and use a simple Belkin no-frills USB switch with the kbd/mouse. It works like a charm - mainly because I don't think it tries to be too clever.
Oh yes - the KVM also looked rubbish on my CRT monitor too - but I traced this to the 'official' Belkin VGA cables - they sucked too. Replacing them with other (not expensive) makes of VGA extension leads improved the video quality on the CRT enormously. This was trivially proved by just using the leads as extension leads, taking the switch out of the equation. When using the Belkin leads, video quality was crap. Again, maybe they've fixed that now - I don't know - but it's something else to be aware of.
Tim
Re:USB? What about the UXGA? (Score:3, Informative)
Re:USB? What about the UXGA? (Score:1)
When I say it does 1600x1200 at 75Hz, I mean it. I'm using a Sony G500 monitor, and an nVidia GeForce DDR video card, and I'm picky about the sharpness of black text on a white background. (I have to look at my code all day long, after all.) This KVM produces surprisingly little video degradation, even at higher refresh rates.
Re:USB? What about the UXGA? (Score:3, Informative)
However, when I bought some heavier duty cables with the ferrite cores on them, all the problems went away. (FYI I bought them locally at Action Computer in Sunnyvale, CA and they weren't too expensive)
Check your cables.
IOgear rocks (Score:3, Informative)
Re:IOgear rocks (Score:3, Informative)
Also, the nicest thing about the unit is the fact that it came with all the necessary cables: 4 monitor cables and 4 USB square-type cables. I've never had the need to purchase additional cables specifically for the KVM. If only all products gave you everything you need...
problems with games, some computers (Score:2)
I have the same unit. Inclusion of cables, and a few favorable comments on USENET, won out over Belkin. We use BlackBox at work, but that's more than I want to spend at home.
The biggest problem I've had so far is that the keyboard isn't responsive enough for action games. I can type fine, but I can't play Max Payne. I'm still investigating this problem, as it could be the USB adapter I'm using on the PS/2 keyboard.
Two of the computers had no problem using the keyboard and mouse: an Intel 810E running Linux and an Alladin V running Windows and Linux. The third system, a VIA KT133A, is not as happy. Windows 98 did not recognize the keyboard or mouse. I had to connect a keyboard directly to dismiss the "mouse not detected" message and install drivers. I have yet to get Linux to recognize the keyboard or mouse on this system.
Re:problems with games, some computers (Score:2)
None have given me trouble, and all find the keyboard and mouse combo (Linux after loading the USB drivers, of course). I play Q3 and related mods exclusively on the Win2K machine, again with nary a problem. I've got a MS Natural keyboard and a MS optical mouse.
I had to resort to a PS/2 keyboard during installation of most of operating systems, and I keep it around for booting, BIOS tweaks and whatnot. I fear the PS/2 keyboard will be a necessity for several years to come.
OpenSSH (Score:1, Insightful)
Re:OpenSSH (Score:2)
Seriously, there are times I just like the full-screen display on my BSD box, or even want to have a local X display. Then there are those times when you won't have sshd running or (god forbid) it actually crashes and you need a local terminal. Sure, if you have it set up you could go in through the serial port, but who wants to do that?
Re:OpenSSH (Score:1)
Oh, I dunno, maybe when the machine is 30 miles away, you fatfinger something, OpenSSH dies, and you don't want to drive in at 3am to go reboot your machine at some random colo site?
Re:OpenSSH (Score:1)
It's exactly this attitude that keeps linux off of the desktop. When will people learn that an important goal of software is usability. If you'd step down from your ivory tower of "31337"-ness for one moment, perhaps you'd see the use of this for the average joe user looking to build a cluster or distributed computing system.
Looking at the comments you've posted, it's clear that you are a linux advocate, of the most misguided sort. How could someone who posted "linux needs games" [slashdot.org] have an attitude like this?
Also, are you aware that OpenSSH has recently been Trojaned?
I got tired of dual boot a long time ago, so for me, a KVM and KDE and Windows XP are my best friends, KDE for work, and XP for play. But high performance clusters probably aren't for the "lowly users", perhaps they should be using 486es with barebones linux 1.1, perhaps then you would be satisfied, because then they would suffer as we did (though it appears from your comment here [slashdot.org] that you are in fact quite young and perhaps do not remember those days).
People developed things like KDE for a reason, you know.
Contradiction? (Score:1)
umm.. right.
You can get better than KVM for little more money. (Score:5, Informative)
I've been looking around for solutions to this problem, because I've been thinking of opening a cybercafe, and I found something called BeTwin. [thincomputinginc.com]
BeTwin is like the inverse of a KVM switch. Instead of having one keyboard, monitor, and mouse control one of a bunch of machines.. it turns a single machine -into- the bunch of machines.
Licences are $80 a head, and you can have up to 5 people independently using a single Windows 2000/XP machine just by plugging 5 USB keyboards, 5 USB mice, and 5 graphics cards into a computer (5 USB speakers too, if you think the USB bandwidth will take it!).. absolutely ideal for cybercafes where processing requirements on each station are low.
I have decided to go with the Linux route, rather than pay these fees, but thought I'd share it anyway.
Re:You can get better than KVM for little more mon (Score:3, Insightful)
Buy another keyboard, mouse, and monitor. That's not a problem KVMs were designed to fix. Think instead about the server room full of machines. Now, what do you do if/when you actually have to access one of those directly (ie, from the console, not over the LAN) (don't focus on the wrong part here. There are reasons you may need to directly access the console, like say your NIC died, or you're in the process of installing the OS. The reason here doesn't matter, what matters is that there are reasons why you would need to access the console directly rather than via ssh or vnc or X or terminal server or whatever)? Wheel out the cart with the monitor and keyboard? Or just go sit down at the station where you already have the monitor, keyboard, and mouse setup, with all the machines connected to Cybex KVM switches (the heavy-duty server room KVM switches are quite a bit different than the 2-port or 4-port switches you'll use at your desktop)? With the latter option, you never have to dig around behind a machine for the cables, or try to get back there to plug in that monitor on the cart. Just hit the hotkey, pick the machine you need to access, and you're there at the console.
Re:You can get better than KVM for little more mon (Score:2)
Simply buy an IP KVM [avocent.com] which supports multiple simultaneous sessions.
Re:You can get better than KVM for little more mon (Score:1)
My experience (Score:4, Informative)
I use KVM switches at work and wish I had one at home. The ones I use are fairly expensive (Blackbox... they make lots of server products) and still leave something to be desired. On high resolutions, it takes a couple of seconds to switch between machines and even after paying so much, you can make out that the image is a little blurred on a 21 inch LCD (from Dell). And most of them dont work too well with laptops.
That said and done, I have to add that they are indespensible. Its amazing how much time it saves especially with keyboard shortcuts (you press Control-Control to get to the KVM and then a letter for the computer you want to switch two). Plus its essential in server rooms where these boxes can be cascaded to 64 or 128 machines. Now if only the good ones were a little bit more affordable for the rest of us....
blackbox makes stuff ? Get the real stuff ... (Score:1)
Everything blackbox has is all another brand of switch with the blackbox logo on it and sold on higher prices. For example, their matrix switch to hold 2 users is a Rose-Technology [rosel.com] switch. It took me a long time to find it what kind of switch they were using and they seem to use Minicom and Rose (mainly). The only difference is the price and the ugly black logo put on another product.
If you are in need with a new switch you should look to these [rosel.com] because the switch has up to 40m support without quality loss of the image; can use a line extender up to 300m and has a exclusive feature to protect your ports by groups and users.
For example user A can access all servers while user B can only look to server 1 and 2, user C can control server 1, 3 and look to server 8 but not control it,
It also has OSD and is expandable to more of these units.
The more-expensive [rosel.com] unit (rack unit) is expandable in any way.
Look at the pdf for more info.
The 2 users * x ports [rosel.com]
The 4 users * x ports [rosel.com]
The high-end series [rosel.com].
Dodgy downloads (Score:1)
Great, more scope to control (or hide) all those pR0n downloading/watching sessions.
I have never really liked USB for certain things (Score:1)
Re:I have never really liked USB for certain thing (Score:1)
Re:I have never really liked USB for certain thing (Score:4, Insightful)
No reason - in your case don't switch. But future PC designs probably won't have the PS/2 port, so if you're buying new keyboards and mice then it makes sense to buy USB variants.
At the moment, connectors are simply a mess. Just think of the number of different types on a typical, well-equipped PC:
- PS/2
- USB (sometimes split into 1.1 and 2.0)
- Firewire
- Serial
- Parallel
- RCA sockets
- MPU-401 compatible (gameport to most, MIDI port to me
- S/PDIF
- VGA
- RJ-45
- RJ-11 for modem
Don't now about DVI - does it take a different connected to VGA? If so, add DVI to that lot. Gives you eleven (twelve including DVI) different connecters excluding the power cable, and we haven't started on the internal mess yet.On the whole, standardising on the smallest number of connectors possible is a good thing. I'd personally like to see USB die as well and everything go firewire (and no, I'm not on a Mac), but that's a pipe-dream that isn't going to happen.
Cheers,
Ian
Value of audio switching.... (Score:5, Insightful)
The clear choice seems the IOGear device- it comes with cables, has OSD, and does not hail from the nauseating Brushed Metal Plastic Alien Bubbles school of design.
Re:Value of audio switching.... (Score:1)
PC Weasels are often better than KVM switches. (Score:4, Informative)
Re:PC Weasels are often better than KVM switches. (Score:1)
KVM switches are okay some of the time, but PC Weasels rock!
For remote management (remote=more than 100m) a KVM switch is not an option. The PC Weasel gets around a problem of the consumer PCs, which are not built to be managed remotely. As such, it's clever hard and software.
But IMHO it is more cost effective to get a "server board" instead of the usual consumer parts to build a server. They often have a serial console for BIOS access built in (like those from ex-Compaq [compaq.com] or a nice description for another OS here [freebsd.org]).
This solves the BIOS problem. Does anyone need remote controlability for anything else?
Re:PC Weasels are often better than KVM switches. (Score:2)
1) The serial BIOSes often do not work very well. Often they have trouble letting you do remotely what you can do locally even though that is what they're supposed to do for you.
2) They don't provide remote reset or watchdog timers. People then resort to additional kludges like remotely controlled power strips, etc.
In general, the PC Weasel "Does It Right".
Re:PC Weasels are often better than KVM switches. (Score:2)
If you have more than 10 servers, are you planning on getting 10 monitors, 10 keyboards and 10 mice, one set for each server? It's a waste of money, it's a HUGE waste of space, and it can't be made to look professional.
A good KVM let's you throw 1 monitor and keyboard at a bunch of boxes. You don't NEED true console access often; however, when you need it, nothing else will suffice.
In a data center environment, you're going to need both remote management and KVM.
Re:PC Weasels are often better than KVM switches. (Score:2)
Re:PC Weasels are often better than KVM switches. (Score:2)
All of which are below the OS level. With no os, you must have console (or remote console)
We have around 150-200 servers lying around. We're back there almost everyday with SOMETHING, be it an initial OS install, hardware failure, or routine maintance. A good KVM system gives you the win of "few monitors, many servers", and also provides remote access to the console for when you don't need to replace something (say, you need to debug a Sun at the eeprom level)
All of which fall into "when you need console access, nothing else will suffice".
Re:PC Weasels are often better than KVM switches. (Score:2)
All of which are below the OS level. With no os, you must have console (or remote console)
---snip
this is exactly what the weasel is for...assuming some of your intel-based servers come from one of the big players, you have probably used the Compaq lights out boards, or the built-in capabilties in the newer generations of Dell servers (older Dell servers used an add-in card like Compaq).
Basically, that is what the Weasel does, only not tied down to any specific manufacturers equipment, and it will not work over an IP network like the lights-out board will (only via an async terminal server. As a nifty bonus, the weasel plugged into the machine also watches and report standard post scan codes, to help quickly narrow down what exactly is dead on your dead machine, if necessary.
---snip
A good KVM system gives you the win of "few monitors, many servers", and also provides remote access to the console for when you don't need to replace something (say, you need to debug a Sun at the eeprom level)
---snip
Why would you should you need a framebuffer card and KVM to do this? I am not a Sun guy, but isn't that what port A and a 1u terminal server is for?
Re:PC Weasels are often better than KVM switches. (Score:2)
For fun, I do solaris for another datacenter that's really into serial consoles, with 16 servers per console server.
The nice thing about the high end KVM stuff, is you can get huge numbers of servers on one system, and at least the one at work (CCC) can send sun and pc views to either sun or pc monitor/keyboard sets.
The nice thing about serial console is that you can telnet (well, ssh) into the console, and get to all of them, even on a 2400baud modem.
The down side is that serial consoles don't scale for spit. Most serial concentrators deal with 16 or less ports per. The 'for fun' datacenter has to have 10 or 20 console servers, whereas at work, we have 1 switch (128 port, and you can cascade several together), and however many monitor stations we need for our usage pattern.
Video quality (Score:1)
Re:Video quality (Score:1)
Get another KVM.
I'm sitting in front of a Sun 21" monitor at 1920x1440@75 24-bit color run through an inexpensive Belkin OmniView SE. Crisp and clear.Raritan is the best bang for the buck, IMHO.
Additionally, the VNC/RDP argument is a horse of a different color. The aforementioned PC Weasel is the only other device that'll let you view the POST/BIOS unless you've got a Compaq/HP with a RILOE [compaq.com] card.
Two different functions.
-JPJ
In my experience... (Score:1)
What about video quality over long distances? (Score:3, Insightful)
Ideally, what I would like to do is put ALL my computers (including my development workstation) in a new rack downstairs, so that all I have on my desk is my monitor, keyboard, mouse and speakers. A perfectly quiet office would be so nice. The problem is, how do I run video from the downstairs rack to my office (easily a 40' run)?
Any suggestions?
Re:What about video quality over long distances? (Score:1, Insightful)
ebay for parts, sure!
machine - $65
video card - $30
cable $14
still under $100
Re:What about video quality over long distances? (Score:4, Informative)
There ya go, home-made long video non-sucky cables made easy.
Re:What about video quality over long distances? (Score:1)
Re:What about video quality over long distances? (Score:2)
So you will be able to run cables much longer before they start to look bad. How much longer? Depends on your individual standards of quality and how long you are trying to make it go. But they did some phenominal cable runs at a lecture hall in my alma mater that did 1600x1200 pretty well with BNC.
Re:What about video quality over long distances? (Score:1)
The problem is, how do I run video from the downstairs rack to my office (easily a 40' run)?
A friend of mine solved the problem in another way. Instead of having the server room downstairs, he put it next to his working room. Only one set of cables (KVM, and one external SCSI CD-ROM) goes to his desk. Cable length is about 2m, so no problem at all. And using a KVM switch, he was omfortably working on 2 computers in a very quiet room.
Of course this is not always possible, but it simplifies the problem a lot, as long as you are flexible about the place of your working room and the server room relative to each other.
Re:What about video quality over long distances? (Score:1)
I have a 50' CompuCable VGA cable, and I see some slight ghosting at 848x480 at 60Hz, but I did chop of one end and solder in a new connector to mate to my monitor.
Try it, maybe you will like it.
Re:What about video quality over long distances? (Score:1)
Re:What about video quality over long distances? (Score:2)
Computer 1 -> KVM switch
Computer 2 -> KVM switch
Computer 3 -> KVM switch
etc.
KVM switch output -> Cybex/Avocent Longview extender [cybex.com] -> One, single cat-5 cable -> Your computer upstairs.
The Longview extends your keyboard, monitor, mouse, speakers, microphone and a COM port up to 500 feet over one cat-5 cable. They work very well and I can see no video loss whatsoever.
KVM = $200 suck. (Score:1)
Re:KVM = $200 suck. (Score:1)
I feel linky today.
Try this. [radioshack.com] (Note: The tip isn't grounded, and this will annoy any of the EEs on slashdot, so I thought I'd mention it).
Re:KVM = $200 suck. (Score:1)
-JPJ
Linksys ok too (Score:1)
PS/2 vs. USB (Score:1)
I've got a PS/2 KVM and trying to figure out how to get the thing to work with a mac is quite an exercise. I would love for this machine to have PS/2 ports. I guess apple just wanted us to be able to plug our mice into our keyboards. Ok, rant mode off.
Re:PS/2 vs. USB (Score:2, Insightful)
Conversely I don't have to shut down every time (not horribly common, but enough to bug me) I dis/re-connect my mouse.
I don't need dead ports on my motherboard. Oh, and thats two less specialized ports on the system.
Re:PS/2 vs. USB (Score:2)
As for the keyboard... I dunno, you'd have to type pretty darn fast to notice a difference. (:
Re:PS/2 vs. USB (Score:2)
Huh? How about backing up that statement... The only problem I see with USB is poor support under linux. Is that USB's fault? Nope. Why do I get the impression your main reason for disliking USB is the fact that it's mainly a "Windows Only" standard... ?
Re:PS/2 vs. USB (Score:2)
For mice, the extra bandwidth results in more frequent updates.
And finally, it could help reduce cable problems. I mean, for example with a KVM, only one cord needs to plug in for both mouse and keyboard if it could double as a USB hub.
*Anything* that could help a KVM reduce cable mess is very good.
For the record... (Score:4, Informative)
Unfortunately, both of these switches require large, boxy power adapters, the kind that don't tend to fit well in most surge protectors. Ideally, I'd like to see power pulled directly from one of the connected computers, but I'd settle for a power connector that moves the box away from the plug itself.
Perhaps my version of the Belkin KVM switch is different from the one they reviewed, but mine requires no external power. It works exactly as they wished it would... using power from the systems themselves.
I have a Windows PC using PS/2 plugged into port 1, an Apple G4 using USB into port 2, and a Linux box using PS/2 in port 3. The keyboard and mouse are PS/2 and the Belkin box effortlessly translates between them.
The problems they mention with USB peripheral disconnect is likely because the reviewer has connected the USB peripherals to the keyboard. You have to think of the KVM as its own USB device and not a hub. It's a KVM switch not a KVM-CD Burner-Digital Camera switch.
I can't comment on the other switch they review, but I love my Belkin KVM switch and I'd recommend it, especially if you have a mixed installation as I do. It works great with very few problems.
Re:For the record... (Score:2, Informative)
Actually, most of the KVM's I've used have this as an unintended feature. It can cause real problems because there are several situations where the KVM can get messed up and you can't control any of the machines. The only recourse is a reset of the KVM, but pulling the plug doesn't do that because it gets residual power from the keyboard and mouse connections to the running machines!
The only safe solution is to physically unplug ALL of the machines from the KVM, then power it down, power it back up and then plug all the cables back in.
The only other choice is to shutdown all of the computers and then power cycle the KVM, but of course since you don't have control of the machines, they can't be shut down nicely (in most cases). This is really not a good solution.
If you're using a UPS, make sure the KVM is plugged into it too because if the KVM loses power, but any of the machines on th KVM don't then you could experience the problems I've just described.
I second that (Score:2)
Personally, I liked that the Belkin did not come with cables. Although that sounds strange at first, I realized that the odds of Belkin supplying the exact cabling that would work in my installation (factors include length, connector types (USB vs. PS/2), quality) were nil.
I would, however, strongly suggest paying the extra bucks for high-quality video cables to connect boxes with graphics displays. I upgraded from a Rat Shack VGA extender cord to a Belkin Pro-series integrated cord, and the difference in picture quality at 1600x1200x85 is noticeably better. I'd almost gotten used to the slight ghosting, but the Belkin cable cured that completely. Feel free to stick the cheap cables on your servers' text displays, though.
I use a MasterView USB KVM Switch (cs-104u) (Score:1)
Degradation of the video quality? (Score:3, Insightful)
Be careful!
All the units besides the IOView degrade the video quality, I understand from long conversations with sales people. The IOView, with a Hitachi Elite 751 19 inch monitor and a Matrox G-450 video card at 1600 x 1200 and 75 Hz, actually gives slightly better quality. Odd result, I know, but I'm testing the IOGear MiniView SE 4-port as I type this.
The Tech Report article about 4-port units [tech-report.com] says, "The other units lack explicit video signal enhancement features, but their quality was the same on both a 17" Trinitron and a 19" NEC AccuSync 95F. Note that this does not mention the video card or the resolution or the refresh rate, indicating that the reviewer was probably not thinking that these were critical. Also, many people are just not good at seeing degradation.
The IOGear MiniView SE 4-port has a VERY funky way of switching between computers. One way, to press a control key twice, is okay, but only goes to next computer in line. The other is amazingly foolish:
[alt]+[ctr]+[shift]+[1 or 2 or 3 or 4]+[Enter]
(See page 14 of the MiniView SE 4-port manual [iogear.com] (NOTE:
According to Samantha Martinez of KVM Switches Online [kvm-switches-online.com] (Samantha@kvm-switches-online.com Phone: 303-604-0237 Fax: 303-604-0724), "The only manufacturers that hold that resolution at that refresh rate are Aten/IOGear and Avocent." (They don't sell the Belkin unit, apparently. Aten makes IOGear. You can buy Aten units directly, but they are a worse buy.)
Note that you get 2 4-foot cables and 2 6-foot cables with the MiniView, not 4 6-foot cables.
Re:Degradation of the video quality? (Score:2)
[alt]+[ctr]+[shift]+[1 or 2 or 3 or 4]+[Enter]
Dude... I don't even think about the keys anymore... now you've messed me up =)
Seriously, though, I have a 4 port PS/2 IOGear, and I mastered that keyboard switch in the first hour of use. My only complaint with the box, in fact, is that since it's a funky design, unless I bolt it underneath the table or something, the cables end up all over the place. I sure wish all the ports were on one side, and that it had the lights and the manual switch on a front panel, so I could put it on top of my desk. As it is, it's just floating back there with my hub and router and dsl model, etc. Thank goodness it doesn't need a power brick!
Oh yah: I also noticed that my work laptop, which was a Gateway Solo 9300, would lose connectivity with the mouse sometimes if I switched away. However, that's got to be a hardware issue on the Gateway side, because all the other machines I've hooked up have been fine. Just a word of warning to anyone with that particular system...
I agree about the cables. (Score:2)
I agree about the cables. Why did IOGear put the keyboard and mouse cables in the front? What could they possibly have been thinking?
There are a lot of Chinese, who work for these Chinese companies, who own only a bicycle, two pairs of black pants, and three white shirts. They are not the sort to worry about convenience in a product they will never own. (I've spent time in Taiwan buying computer parts.)
Re:I agree about the cables. (Score:2)
Maybe so, but a cable sprawl like this implies a generosity of real estate, something I doubt many of those hard workers have. More probably, it was just the simplest design to get a single-layer PCB or something.
I can't believe it's for ease of use, because reliance on colored ports to distinguish between mouse and keyboard is no good when you're fumbling in the dark under the desk, and the status LEDs are useless when it's under there, too.
Still, I love its crazy fake space streamlining, and the cables are surprisingly good for being so thin.
Re:Degradation of the video quality? (Score:1)
Changing the model without changing the model #. (Score:2)
I didn't try the Belkin because Samantha told me about this.
I agree about the Aten form facter. Amazing mistake.
There is an issue with IOGear changing the model without changing the model number, so make sure you get fresh stock. Order from a big supplier.
How can a switch box improve video quality ??? (Score:2)
OK, I know you qualified this as an 'odd' result, but can someone explain how this could possibly be true ? If you're plugging the computer into the switchbox, the signal the SWITCHBOX is getting is the same signal the monitor would be getting if you didn't use the switchbox. But you're running more cable between the switchbox and the monitor and you have a device in between, to boot.
So how is the switchbox able to increase the video quality without introducing its own noise ?
I don't know. (Score:2)
A friend pointed out that there must be something imperfect in the way the Matrox card outputs its signal. Also, the difference is very small (but unmistakeable). I did not try the IOGear with the latest Matrox cards (G-550). I was too busy at the time.
Noise is not an issue here. The signals are very high level.
Wrong - darned salespeople! (Score:2)
I'm using the reviewed Belkin KVM with a Samsung SyncMaster 900NF fed from a Geforce2 at 1600x1200 at 75hz. I'm using an integrated video+USB cable made by Belkin, and have no perceivable degradation whatsoever. I used to have slight ghosting with cheap cables, but now there's none at all.
If you're a picky graphics designer-type, then you may "see" artifacts that noone else in the world can pick up, but the setup is beautiful for regular people.
awful belkin usb switch (Score:4, Informative)
The first thing was that it didn't work with my keyboard (logitech wireless). The F7 key was useless when plugged into the KVM. This was relatively minor, and they promised a firmware upgrade to fix it. Also, for those that care (I'm not one of them) the "internet keys" don't work.
The other problem I had was also keyboard related. The KVM has a keyboard emulator, which sends keyboard events to the computer, after receiving them from whatever keyboard you have plugged in. If you hold down a key for 3 seconds, the keyboard emulator fakes a key release. So scrolling stops after 3 seconds, and if you're ctl-clicking to select stuff, and you take more than 3 seconds to do it, suddenly the ctl-key is no longer pressed down, and you select just one item. I got the impression that this wasn't going to be fixed in firmware, but rather in the next revision of the product.
Also, the response time was sluggish at best, typing felt like i was in an ssh session over a slow link. Oh, and keys stuck sometimes.
I was planning on getting the IO Gear one instead, as I am told it doesn't have the same shortcomings. Here's hoping.
IOGear with 'USB sniffing' is the best (Score:4, Informative)
I have used switches by Belkin, IOGear, Cybex, and a few others and they aren't even close in quality.
Only the IOGear does not display any video ghosting. IOGear video is rock solid with no fuzziness.
I switched to USB after I saw that IOGear uses 'USB sniffing". This neat feature eliminates that 3 to 4 second delay that every other USB KVM has and makes the switch as responsive as a PS2 switch.
IOGear has top quality stuff but their cables are a bit expensive.
Spoofing is a must, was: IOGear w/ 'USB sniffing' (Score:2, Informative)
If you only switch occasionally, this might be ok. If you frequently switch (as between RISC workstation and PC), it's unacceptable.
4% of USB KVMs are actually just simple mechanical switches. They have all the same problems as above, plus, striclty speaking, they violate USB rules, and can have nastly malfunctions if they don't have correct precedence for power-on/off (as USB connectors do).
1% of USB switches, just now entering the market, have "spoofing", aka "sniffing", aka emulation of devices. A correctly implemented spoofing switch never lets any host see a disconnect. Designing this is far from trivial. USB is complex, and the varieties of keyboards and mice are effectively infinite if you're trying to chase them all for purposes of emulation.
In addition to the IOgear mentioned above, there is only one other spoofing switch that I'm aware of, and it isn't fully debugged yet.
In the meantime, I recommend:
Wait for this USB KVM situation to get sorted out. And it will need to soon, as PS/2 ports will be vanishing from new machines next year (and already have from many 64-bit platforms).
Belkin Caveats (Score:4, Informative)
The belkin SOHO series (which I am using now) don't seem to reset PS/2 mice as reliably as the older Omnicubes (which I also use). Although, you don't need AC power for the SOHO series (it will draw power from keyboard ports). I had to return two units (over the course of 1.5 years) that would change channels (with loud beeps) in the middle of the night randomly - even though the PCs were off and wouldn't stop until I unplugged every single cable (including monitor). Adding an AC adapter from a spare omnicube fixed that problem.
Belkin does have a 3 year warrenty on their KVMs though, which has proven helpful for me.
Re:Belkin Caveats (Score:2)
I don't have any KVM, but I would think ctrl-q would unfreeze it in lieux of scroll lock, it works in non-kvm situations.
Re:Belkin Caveats (Score:2, Informative)
Also if you're using a wheel mouse on Linux with IMWheel (IMPS/2), then the Belkin switches will mess up the mouse severely when you switch. Typically, once you switch back, the pointer will be stuck in the corner. Moving the mouse will move the pointer a short distance from the corner, randomly register button clicks and snap the mouse back to the corner! On Caldera Linux, it's the upper right hand corner and on Red Hat Linux, it's the lower left. In either case, it makes the machine practically unusable.
If you know your keyboard shortcuts, you can shut down X and restart it and everything will be fine. Naturally this isn't a good solution, but the other day, I discovered that if you simply switch to one of the virtual terminals (ctrl-shift-F1, or F2 through 6) and then switch back to X (ctrl-shift-F7 or 9 on some systems) then you can get back control of the mouse without having to shut down X.
The Belkin KVM also causes problems with OS/2, but it only loses scroll information, so it's not critical. You have to restart the Work Place Shell or reboot to get it working again.
These are fairly serious problems that make the Belkin KVM's effectively useless under certain configurations.
Iogear Miniview (2-port) rocks (Score:3, Interesting)
I can't see a difference in the video quality (but I can't remember how it was before either...).
Anyway, a great buy for SOHO. And I'm not working for them...
Garbage (Score:1)
Re:Garbage (Score:1)
If you don't like the story, stop reading, and quit your bitching, asshole.
Re:Garbage (Score:2)
Actually it's a PERFECT article. I've been comtemplating a KVM switch at home for a few months now. I almost bought the belkin soho set but balked at the price. The only usb device I need to share is my mouse. My linux box has a usb hub with my sidewinder and sandisk cf reader.
This article helped tremendously and I'm looking forward to reading the responses on other possible models to look at.
So in closing, fuck you for thinking your opinion is the only thing that matters. I'm not one to support slashdot for the same lame stories but this one was one of the better ones.
prick.
Re:Garbage (Score:2)
This article actually is generating some of the realworld insight that I was looking for before making my purchase. You can't get that with a magazine article. I wasn't so concerned with the article linked as I was with the responses of readers.
Again, apologies for the language. It didn't help my point and actually detracted from it.
Re:Garbage (Score:1)
RIS Boot and USB KVM's (Score:1)
Anyone know of any solutions? Compaq and Belkin blame each other....
Why choose between KVM and VNC? (Score:2)
Check out StarTech KVM products [startech.com]. I think you can use that VNC box with other companies' KVM's also...
KVM II (!(2*KVM)) (Score:2)
It's a classic case of when someone says YMMV, and you find out that sure enough, your mile is not == 5,280 feet.
For instance, with a stock RedHat 7.3 kernel (2.4.18-3 through
Their advertised keyboard hot-switching doesn't apparently like the MS Internet Keyboard Pro, either. So, it's either manually reach over to the KVM and select the system you want, or curse at the folks at IOGear who are patently clueless.
Otherwise than that, works great on the standard Windows boxes and the Mac platform.
But, for now, it's pretty much SSH/X-windows forwarding to use that Linux box.
Re:Larger applications (Score:1)
What I'd really like to see is a modular KVM. You know snap however many you need together like lego.
It would also be great if they could make them two dimmentional so that you could have more than one se t of keyboard, monitor and mouse and switch any machine to any monitor. I know it sounds strange, but at work, I had six computers on my desk and two monitors. The main machine went to one monitor and the rest to a KVM and the other monitor. That was great most of the time, but occasionally, I needed to see two of the machines that were on the KVM at the same time and even though I had a KVM and two monitors, I had to plug things in manually to get what I wanted.
Re:Larger applications (Score:2)
Re:Support for New Apple LCD Monitors? (Score:2)
If you really insist on getting an Apple display and you have some cash to spare, get the ADC display, and buy a 3rd-party 17" LCD to use on the VGA port on the G4, and use that as the G4's secondary display and the primary for the other machines hooked up to the KVM.
~Philly
Re:A KVM switch with a VNC server!!! (Score:2)
Console servers are very nice for some situations where you need to control a number of servers remotely. Sun sells these as do other vendors (Avocent sells them I think.) Remember, they're different from KVMs in that you don't plug in keyboards, mice and monitors, usually just a serial port.
If you need X (GUI environment), using ssh over a switched subnet is the best performance I've found. Have a central machine running X, ssh to the other machines and export the display variable to your central machine. Easy to control a number of machines from one monitor, keyboard and mouse, especially if you're using a multi-screen window manager like WindowMaker and its kin: Just setup a virtual screen for each machine and you're ready to rock and roll.
Re:A KVM switch with a VNC server!!! (Score:2)
Unfortunately, their DSView app only runs under Windows.