Bit OT: KVM switches

[Lobster]

I've been wondering whether it would be in some way feasible to arrange to have a second PC sitting under my desk, sharing the same keyboard, monitor and mouse as my current PC; a bit of googling has demonstrated that I'm evidently not the first to think of this and that (which will be no surprise to many readers here) there is a technology out there known as a "KVM switch" which seemingly will precisely fulfil my requirements.

However, I've been unable to find any really basic info about these things, and there are loads of them around at hugely different prices. Can anyone kindly point me at some useful background info, or give me a quick rundown on the important points? Can they be 'hot-switched'? Can they cause performance issues? Anything else I need to know? (This is very much a nice-to-have, so I'm really only wanting a cheap'n cheerful solution).

Cheers David

[Grant]

12 quid plus delivery from ebuyer.co.uk for a 2 PC version including cables.

Reviews look OK.

[Andrew Gabriel]

At the bottom end, they are a set of connectors for keyboard/mouse/ video, with a 2 (or more) way switch. Then you go up to the ones which have software control, i.e. hotkeys on the regular keyboard to switch between systems, remembering mouse programming done by each system and reprogramming the mouse appropriately when you switch, simulating mouse and keyboard continuously to all systems so they don't boot and think keyboard is disconnected or the OS doesn't see the mouse/keyboard disconnected when you switch over, etc. Depends which features you want. The bottom end ones are very cheap, so you could start there and try one out.

These questions may depend which OS's you run, which you didn't say.

OTOH, if you are running UNIX, you only need a single desktop for any number of systems, since its desktop applications run over a networking stack anyway (to a first approximation), and can be used remotely just as easily as locally. There are software technologies like VNC which can do this for Windows too, but it's not such a well integrated feature in Windows as X Windows on UNIX.

[Goonerak]

Possibly one of the best gadgets I've bought. I've got one that I use for the desktop PC and the laptop docking station. For my particular switch, you press Scroll Lock twice in quick succession to change from one PC to the other. Very simple to use.

[Grunff]

The hardware may be ok, but ebuyer are most definitely to be avoided.

[Grunff]

They're great. Yes, they can be hot-switched, that's one of their best features. If you want a good quality one, go with a Belkin.

[Grant]

I know there are lots of horror stories about them - they don't accept phone calls for instance.

However, for £16 or so the OP may decide it's worth a punt.

I bought a motherboard, CPU, fan and RAM for £86 delivered from them last week - it arrived a day early.

[Stefek Zaba]

A basic 2-port or 4-port KVM should leave you with change from 100 notes

- there's 2-port ones which sell for around 50 notes. They can all be hotswitched, typically having both a button on the KVM unit itself to cycle through the input sources, and through a partly-configurable selection of keyboard fingerings - e.g. ctrl-alt-shift-numpad+ or some such.

A decent midrange brand is Adder - if you pop over to

you'll get an idea of prices and features. They've got exotic run-over-hundreds-of-metres-of-Cat5 stuff, and run-over-IP, but the 'desktop KVM' range is all you need...

As to affecting performance - yes but not much. If you do high-end Photoshopping, or are fussy about screen resolution/performance for other reasons, you'll find things a little bit fuzzier through a KVM than going direct; quality of cables affects this to some degree. But for 'typical' desktop use, the convenience of a KVM usually Wins. One half-way house that can work is if you have a dual-input monitor - arrange a direct connection for your 'real', 'main', 'precision' machine, and use the other videoport for your KVM input - second desktop machine, laptop docking station, and so on.

The other PITA is the current industry transition between PS/2 and USB for connecting your K and M to your machine. The older all-PS/2 KVMs are still a bit cheaper, but prices are levelling out. And V isn't utterly standard either - for quite a few years it's been reasonable to assume the 3-row VGA-style D connector, but more recently the 'all-digital' LCD flat-panel connections have become more widespread.

HTH - Stefek

[Lurch]

On Sun, 30 Jan 2005 16:20:47 GMT, Lobster strung together this:

Not really much to say about basic KVM's. I've just got a cheap ebuyer

4 port one and it comes with 4 sets of cables and a power supply so you don't miss up the POST info. It's hot switchable too, I've got it sitting here supplying my desktop PC, a server and spare ports for 'works in progress' so I don't have to start digging out spare keyboards and mice etc... for testing.

All in all, it does what it says on the tin. A thumbs up from me.

You can also get KVM switches to switch sound and serial ports etc... if needs be. Depends what you're after.

[Grunff]

Well, I won't add mine to the pile of horror stories, but suffice to say I wouldn't buy from them again if it was free.

[Huge]

There's a much easier solution, if both machines are networked...

a VNC server on one machine and a client on the other. Then you can open a window onto one machine from the other.

I use it here.

[Andy Burns]

"mirage" display driver available for use with the latest development version makes a big increase in speeds and accuracy of screen refresh if you have win2k or winxp, even though is "beta" software has been OK for me on several machines for several months ... usual caveats apply ...

[Vortex]

I've got a KVM switch but IMO this:

a better gadget (if you're a true anorak and you don't own one then you're life is seriously incomplete).

Apologies for drifting OT.

David.

[Rob Nicholson]

How about

- bought tons of stuff from them over the years. They too don't take telephone calls but their returns policy is pretty decent.

Rob.

[Rob Nicholson]

Interesting, didn't realise that VNC was open source. We use

at work and that's free too.

Rob.

[Rob Nicholson]

Handy for transferring data off old hard disk onto new PC I guess.

[Grunff]

[Rob Nicholson]

Belkin is good kit too.

[Andy Burns]

Oh yes, nothing wrong with RealVNC, IIRC they are (some of) the original people who originally developed VNC at Olivetti Labs, there are various forks of VNC which "nudge infront" with new features from time to time, the best ones usually make it back into the other versions ...

[Bob Eager]

A bit more expensive than ebuyer, but the Belkin (mentioned by someone else) can be had 'used' for 25 quid plus VAT, and non-ruious postage, from

This guy knows the meaning of service, too.

You'll need to look (strangely) in the Multimedia section on the site.

Cables are extra and what really whack up the cost. Cheap KVMS with included cables are what they say - cheap.

That said, I picked up a couple of Belkin KVMs on eBay recently for 3 quid each (sans optional PSU and cables, though).