YAKQ (Yet Another KVM Question)

[ironcoder]

I asked a question on this before and I got a couple of good leads, but I am having trouble finding a 4 port KVM with PS/2 keyboard and mouse connections with DVI screens that has any good reviews.

A few people said IOGEAR was a good brand, but they don't offer one in this config.

Basically what I have in my office is 4 boxes, 4 screens, 4 keyboards, and 4 mice. I want to put 3 boxes about 3 meters away from me and the other box on the other side of the room which although it's actually probably 3 meters it's going to take a lot  more cable unless I run cabling over the floor which I don't want to do.

This situation is out of control and I'm not sure what to do. First I was thinking about buying a good KVM and ditching most of the crap and just having one keyboard and maybe 2 screens on my desk. But none of the KVMs except for maybe multithousand dollar rackmount jobs claim to offer enough DVI resolution to run dual head over a KVM. What's more scary is that almost all the KVMs get bad reviews saying mice don't work or other stuff. I don't mind paying a fair price but this stuff has to work.

After looking at newegg (which I can't buy from anyway but I use it as a representative site because of the reviews and prices) I started thinking maybe I'm better off with extension cables and putting up with 2 screens and 2 keyboards on my desk. The other two boxes I don't really need to run all the time and part of the time I do run them it's enough for me to run headless or even run VNC sessions.

How much do I lose if I go back to VGA instead of DVI on my screens? I don't game, these are all development boxes and servers, but I need crisp detail because I'm too damn old to see fuzzy screens anymore. That might give me more KVM choices but I still want to avoid USB keyboards because I don't run Windows and I don't trust all of the weird OS I run to work with USB keyboards (which I don't have any of anyway) Just something I want to avoid.

Right now my config is one box and screen on my desk, 2 boxes screens and keyboards each on a rolling work cart, and the last box (big server) on the floor with a screen and keyboard on a cabinet. I don't like having to roam all over the room to get anything done and this layout just takes too much real estate.

Any ideas how to simplify things from you guys with too much equipment? Thanks.

[InSanCen]

VGA vs DVI... It depends on the monitor.

On a decent screen, you will lose little, if anything in "sharpness". By the same token though, a cheap £100 PVA screen will probably have a crap signal path on the analogue.

I wonder if You can daisy chain KVM's? Sort of a 4>2x KVM>1xKVM affair. Might work out cheaper if you do switch to VGA. Depends if you can get a Bulk or Trade Price on them (I do... it would be cheaper, but I can't tell you my supplier, sorry).

[rdh]

Some KVM's are designed to be stackable, but don't assume it will work on a particular model - check before buying.

I suspect PS/2 KVMs will be harder to find, especially on DVI models.   Unless you really need to have PS/2 output from the KVM, it's probably simpler to get a USB model and connect your keyboard and mouse through a PS/2->USB converter.

If you can, get a KVM with hotkey switching, so you can switch from your keyboard.  That gives you the option of placing the KVM and it's attendent forest of cables in places that are out of arm's reach.

Check to see if the cables are included when you compare prices.

I have been using an Iogear GCS 1764 for the past few years, which is a four-port USB/DVI model.  I'm pretty happy with it.  
Mine's an older revision, with a max spec'd resolution of 1600 x 1200 - I'm running at 1680 x 1050 - though newer revisions claim to handle 1920 x 1200. If your monitor needs it, the same company does sell dual-link models capable of much higher resolutions.
The only downsides I've noticed are that the switches on the front panel are a bit flimsy (but I don't use them often).

[ironcoder]

Thanks guys. Maybe you are right about the ps/2->USB converter, if they work it would make picking a KVM easier.

Any other ideas on simplifying your office when you have too much junk spread out all over the place? The more I think about it the more I am thinking about running dual head and just VNCing to the rest of my network.

[ironcoder]

Thanks guys.  I can't use a PS/2 to USB converter because I have some machines/OS that may not work with USB inputs. I can't afford to find out the hard way and I often install new OS so I'm staying with PS/2.

Any other ideas on simplifying your office when you have too much junk spread out all over the place? The more I think about it the more I am thinking about running dual head and just VNCing to the rest of my network.

[timw4mail]

Thanks guys.  I can't use a PS/2 to USB converter because I have some machines/OS that may not work with USB inputs. I can't afford to find out the hard way and I often install new OS so I'm staying with PS/2.

Any other ideas on simplifying your office when you have too much junk spread out all over the place? The more I think about it the more I am thinking about running dual head and just VNCing to the rest of my network.

It seems really strange to me that you would have computers that wouldn't accept USB...how old are those dinosaurs?

[ironcoder]

Like I said it's not the computers, it's the OS I run on them. Maybe these OS do all work with USB keyboards and mice but I haven't tried since I don't have any USB kbs or mice. I also occasionally install weird OS and I don't want to get stuck with something that doesn't work.

I'm goin to try VNC everywhere and if that works I will run dual head on my main workstation and just VNC or SSH to my other boxes and that should be better than a KVM.

Now I just have to find a place where I can buy extension DVI, keyboard and mouse cables that ships internationally.

[timw4mail]

Like I said it's not the computers, it's the OS I run on them. Maybe these OS do all work with USB keyboards and mice but I haven't tried since I don't have any USB kbs or mice. I also occasionally install weird OS and I don't want to get stuck with something that doesn't work.

I'm goin to try VNC everywhere and if that works I will run dual head on my main workstation and just VNC or SSH to my other boxes and that should be better than a KVM.

Now I just have to find a place where I can buy extension DVI, keyboard and mouse cables that ships internationally.

Is it a really old unix flavor, or < Windows 98 ? Otherwise the OS should not have a problem with USB.

[ironcoder]

Solaris 10, which is notorious for horrible x86 support is one I am using and wondered about. I have another box running OS/2 Warp. The rest of my machines run newish releases of OpenBSD, FreeBSD, Slackware, and Slamd64. I never know when I will find something interesting and try it, so I like to stay away from anything that requires software support as much as possible.

[InSanCen]

Solaris 10, which is notorious for horrible x86 support is one I am using and wondered about. I have another box running OS/2 Warp. The rest of my machines run newish releases of OpenBSD, FreeBSD, Slackware, and Slamd64. I never know when I will find something interesting and try it, so I like to stay away from anything that requires software support as much as possible.

An estoeric choice of OS's...

I wholeheartedly approve!

[timw4mail]

Solaris 10, which is notorious for horrible x86 support is one I am using and wondered about. I have another box running OS/2 Warp. The rest of my machines run newish releases of OpenBSD, FreeBSD, Slackware, and Slamd64. I never know when I will find something interesting and try it, so I like to stay away from anything that requires software support as much as possible.

I am 99% sure Solaris does support USB keyboards and mice. I haven't played with Solaris recently, but the (fairly) recent version I've got does support USB keyboards, mice, and flash drives.

I've no idea about OS/2, though.

[ironcoder]

I am 99% sure Solaris does support USB keyboards and mice. I haven't played with Solaris recently, but the (fairly) recent version I've got does support USB keyboards, mice, and flash drives.

I've no idea about OS/2, though.

I'm sure it hasn't got worse so if you have an older version and it works it must still work. Unless you are using OpenSolaris, in which case there is no guarantee Solaris works the same way. Which version exactly are you running?

[ironcoder]

An estoeric choice of OS's...

I wholeheartedly approve!

Thanks. Yeah I'm a software guy and I always hated Windows even though I actually do almost no coding for x86 I appreciate a good OS.

I only have OS/2 Warp because it runs on my MVS box. Otherwise, I don't really like OS/2. I've also tried eComstation and it didn't do it for me either. I know OS/2 has a dedicated fan base but it's not my thing.

I haven't found one OS for x86 that does exactly what I want or works exactly like I want so I've been running too many machines so I can get this or that feature or do business this or that way. I guess I could crowbar one of them to work like I want but I think it's important to adopt the philosophy for each OS and not try to get too wierd with it or down the road you will break something and paint yourself into a corner. You should really use each tool as it is designed to be used to get the most benefit.

Things are getting out of control in my office so I am probably going to rip out all my multiboots and settle on one OS per box. I really like the fact that Slackware and Slamd64 allow you to manage your own dependencies. I wind up with a very lean system and no packages I don't want. I like all of the BSD family each in its own way but they all have issues that keep me from using it for a main system. I think the main thing stopping BSD from really making progress is the reliance on gnu toolchain. It's not going to happen any time soon but if BSD would come up with their own toolchain and still work with the wretched gnu bootstrap and config scripts they could avoid a lot of problems that make it a pain in the ass to compile whatever you want. For now it's just much easier to take anything and slap it down on a good Linux like Slackware. I know these comments may ruffle a few feathers but this is my opionion after using this stuff for a few years and I would like to see BSD be completely independent from gnu-anything for their own good. Until then you either have to use prepared packages or learn more a lot more than average about the OS and be a reasonably proficient C and C++ coder to be able to build everything you want. I don't use those languages so it's more than I have time for right now.

[timw4mail]

I'm sure it hasn't got worse so if you have an older version and it works it must still work. Unless you are using OpenSolaris, in which case there is no guarantee Solaris works the same way. Which version exactly are you running?

I'm not exactly sure, but its one of the free developer versions of Solaris. I'm pretty sure its still the Solaris 10 branch.

[ironcoder]

hmmm what does uname -a tell you?

[timw4mail]

hmmm what does uname -a tell you?

I'd have to install it to find out... and to do that, I'd have to know which version it was, because I don't seem to have the installation DVD anymore.

Sorry I couldn't be of more help than that.

[talis]

It sounds like you could probably solve some of your problems for free with a mix of Synergy and VNC.  Maybe have 2-3 screens on your desk hooked up to 2 PCs.  Use one PC running dual head as a primary, and the other as a virtual terminal for the rest.  Synergy would let you control the whole thing with a single mouse/keyboard.

[ironcoder]

Yeah that's the conclusion I came to a few days ago. not Synergy what ever that is, but I'm going to run VNC servers on all my other boxes, and I'll run a dual head main workstation with a VNC viewer.

I've been testing it and so far so good, I just need to find some good quality long cables so I can move stuff where I want it. I'll have to try a few different combos, tightvnc seems slow over my LAN which surprised me.

[rdh]

not Synergy what ever that is

Synergy lets you share a keyboard, mouse and cut buffer (but not a monitor) across multiple physical hosts.

At work, I used to have two monitors side-by-side, one connected to a Windows box and the other to a Linux box.  I installed Synergy so I could use the Linux box's keyboard and mouse with both.   Pretty handy.  It has some downsides, like no encryption [1] and it's a little flaky once in a while, but I used it for several years and was mostly happy with it.

If you're using VNC, you probably don't need Synergy.


[1] They recommend tunnelling it through other encryption programs, such as ssh.   I was running Linux on slow-ish box, a Pentium II 350, which made the encrypted link annoyingly laggy when the box was busy.  I worked around that by running unencrypted over a dedicated network cable.

[ironcoder]

Thanks for the link. Sounds kind of cool actually but it would be overkill for what I need it for.

VNC is not performing that great for me even in testing on the same box. I mean I can tell the difference in speed and I think I shouldn't be able to. Functionwise it's great but it's slower than it should be. I'm going to try different settings and a different server and client to see if I can improve performance. The boxes I have now are all modern fast boxes with plenty of memory.

I'm going to be using all this inside my lan so encryption is just overhead I don't need.

[timw4mail]

Thanks for the link. Sounds kind of cool actually but it would be overkill for what I need it for.

VNC is not performing that great for me even in testing on the same box. I mean I can tell the difference in speed and I think I shouldn't be able to. Functionwise it's great but it's slower than it should be. I'm going to try different settings and a different server and client to see if I can improve performance. The boxes I have now are all modern fast boxes with plenty of memory.

I'm going to be using all this inside my lan so encryption is just overhead I don't need.

Well, I would suggest LogMeIn...but you need either OS X or Windows for that...

[ironcoder]

That's the tail wagging the dog!

[talis]

I find just exporting the X session over ssh is usually faster then using VNC or an external app.  Just use the -X -C switches (export X, use compression).

It does get a bit hard to track what app is actually running on what machine after a while though.

[ironcoder]

Doesn't that only allow you to run one X app at a time?

[talis]

Doesn't that only allow you to run one X app at a time?

Not as far as I've ever seen.  But then I don't tend to have more then a bunch of xterms and a browser open at any given time.

[rdh]

I find just exporting the X session over ssh is usually faster then using VNC or an external app.  Just use the -X -C switches (export X, use compression).

Doesn't that only allow you to run one X app at a time?

Nope.   It just carries the X protocol requests from the remote box to the local X display, so you can run as many as you want.

There're actually a number of ways to do remote displays:
 * ssh's X forwarding only works with OS's that use X displays, of course.
 * Windows displays can be exported using Windows' native Remote Desktop Client protocol ("RDC") with a Windows client or with the freeware "rdesktop" client.
 * VNC has the advantage of having been ported to quite a few kinds of displays.  
You can mix and match any of those that fit your needs at a given moment. There may well be other choices, too.

VNC is not performing that great for me even in testing on the same box. I mean I can tell the difference in speed and I think I shouldn't be able to. Functionwise it's great but it's slower than it should be.

Slower than it should be?   Not necessarily.  Sure, it's not as fast as we want it to be, but consider: You're using software to watch the windowing system for changes as trivial as mouse motions, package them up and ship them over a network link (even if the link is on the same machine) and draw them remotely.  VNC is not native to any windowing system, and has to tie into them using tricks specific to each, some of which can be pretty ugly or inefficient.  

RDC is pretty efficient for Windows systems, which is not too surprising as it's built directly into Windows by Microsoft.  I can play video through it (!) without much pain (excepting that I haven't tried to figure out the sound set up through "rdesktop").  That is, you can tell the difference, but it's pretty good.

My recommendation is to use ssh for X, RDC for Windows, and VNC everywhere else.

EDIT: for clarity, I mean: "ssh for remote boxes that use X, RDC for remote Windows machines, and VNC for anything else or where ssh or RDC don't work for some reason."

[ironcoder]

I tried x forwarding a few years ago and I never got it to display a complete desktop session. When I asked around everybody said that was the way it works and isn't a complete solution unless you just want to run one app.

If somebody can tell me how to get a desktop from another box using SSH with x forwarding that would be way cool and solve my problems.

I understand the job vnc is doing in general but I feel it's slow anyway. I would expect this level of performance over the net but not inside a gigabit lan. I have to look to see if there is some unnecessary compression going on or anything else that I can tweak that should make it faster.

I don't run Windows so none of that other stuff matters. Thanks guys.

[itlnstln]

Around work, I use RDC a lot, and even when logging into severs about 20 miles away, RDC feels practically real-time.  Even at home over 7 mbps cable, RDC barely lags, although, sometimes, I have to turn off some unecessary features.

[itlnstln]

The only thing about RDC, though, is that sometimes, some software won't let you use it over RDC.  PowerTerm is one.

[rdh]

I tried x forwarding a few years ago and I never got it to display a complete desktop session. When I asked around everybody said that was the way it works and isn't a complete solution unless you just want to run one app.

If somebody can tell me how to get a desktop from another box using SSH with x forwarding that would be way cool and solve my problems.

Ah, I think I see what you mean.  Are you looking for a way to leave a desktop running remotely and connect to and disconnect from it at will?

ssh just passes X protocol requests back and forth, so I'm pretty sure it won't do that by itself.

It occurs to me it might be made to work with some additional pieces of software, though.  (Kinda like "screen", but for X instead of a command line, if that makes any sense to you.)  I'm not familiar with anything like that, though it might exist.  I'll do a little poking around later and let you know if I find anything that looks useful.

[ironcoder]

Ah, I think I see what you mean.  Are you looking for a way to leave a desktop running remotely and connect to and disconnect from it at will?

No, not really. I was planning to SSH into each box and start a VNC server running on it rather than leaving one running as a default.

If I'm going to do X forwarding I can also live with something I have to start manually. But after that I want to be inside the WM (fluxbox for example). Is this possible?

I'll do a little poking around later and let you know if I find anything that looks useful.

Thank you.

[talis]

No, not really. I was planning to SSH into each box and start a VNC server running on it rather than leaving one running as a default.

If I'm going to do X forwarding I can also live with something I have to start manually. But after that I want to be inside the WM (fluxbox for example). Is this possible?



Thank you.

Its a bit weird when you run something remotely over X.  If you consider running a remote app on a local machine:

-The desktop you see is the local machine desktop.
-On that desktop you have a terminal window open, with an active SSH session to the remote system.
- If you launch an app using that ssh session, the app is actually running on the remote machine, but the window is displayed on the local machine (and looks exactly like you were running it locally.

For example:

If I ssh -l -X -C , then run  >> firefox & I will get a firefox browser window on my local machine, thats actually running on the remote machine.  As long as you launch the application, then push it to the background on the remote, you can launch another.  Where the confusion comes is the desktop is still the local machine desktop (you can't see the remote machine desktop).

Here we go, a pictures worth a 1,000 words :

The desktop is my local desktop (debian under virtualbox).
The top left terminal is my ssh session to the remote machine.  Any X apps you launch here will display on your local machine.
The bottom left terminal is an xterm running on the remote machine  (notice how it says (on Bell) in the top bar).
The Firefox window is also running on the remote machine (again note it telling you where its running).

[ironcoder]

Excellent explanation, thanks a lot. This may actually work for me. I'm in the middle of slapping down Solaris 10 for the zillionth time. After that I'll try what you said.

Thanks again.

[ironcoder]

For some reason this doesn't work for me. I get an error saying

Error: no display specified

Must be something minor, but so far no joy

[lal]

The ssh server must have ForwardX11 (or similar) enabled.  Run ssh client with option "-X" to start X apps.

[lal]

You can also start a complete desktop environment on a remote machine that displays on your local screen. You have to start a second X server if there's one running already.  Command looks something like this (can't test right now, and depends how the X session is typically initialised on the remote host):

startx "ssh -X remotehost Xsession" -- :1

[ironcoder]

The ssh server must have ForwardX11 (or similar) enabled.  Run ssh client with option "-X" to start X apps.

It's not 100% clear from the man page but it looks like -X is a session level override, so you shouldn't have to specify X11 forwarding in the target ssh.conf. But maybe this is the problem.

[ironcoder]

You can also start a complete desktop environment on a remote machine that displays on your local screen. You have to start a second X server if there's one running already.  Command looks something like this (can't test right now, and depends how the X session is typically initialised on the remote host):

startx "ssh -X remotehost Xsession" -- :1

That would be great. I'll check it. Thanks.

Edit: whoa that was wierd. Close but no cigar, I just recursed into a second complete X session on my local system. When I ctrl-alt-backspace it killed that new one and I was back in Kansas again LOL.

[lal]

It's not 100% clear from the man page but it looks like -X is a session level override, so you shouldn't have to specify X11 forwarding in the target ssh.conf. But maybe this is the problem.

The *server* must allow it, too.  That would probably mean /etc/ssh/sshd_config, not ~/.ssh/config.  Add "X11Forwarding yes" to /etc/ssh/sshd_config on the server.

[ironcoder]

Thanks, I knew what you meant/what to look for, the confusion was just from what I read in the man page which makes it seem like if you specify -X on the command line you *don't* have to set it in SSHD's config.

I'll try this and get back to you. Thanks.

[ironcoder]

Yeah that was it apparently. As you said, you have to enable X forwarding in SSHD.

This is very cool so far. But, I'm not getting WIndow titles like Talis, so that is a very big problem. It's easy to lose track of what apps are running on which box.

Still haven't got a whole desktop running over the SSH link, though. When I do startx on the remote box it actually starts the WM on the remote machine!

[talis]

This is very cool so far. But, I'm not getting WIndow titles like Talis, so that is a very big problem. It's easy to lose track of what apps are running on which box.

The titles are likely more a function of the local WM then anything else (whatever the default version of Gnome that ships with Debian in this case).  I hadn't remembered seeing the titles telling you where it was running before, so it may also be a newer feature.

[ironcoder]

Thanks. I guess these are a couple of good choices, having either certain apps forwarded or using some kind of VNC. Now I'm going to look at the NX clients and see if they offer what I'm looking for.

[timw4mail]

Yeah that was it apparently. As you said, you have to enable X forwarding in SSHD.

This is very cool so far. But, I'm not getting WIndow titles like Talis, so that is a very big problem. It's easy to lose track of what apps are running on which box.

Still haven't got a whole desktop running over the SSH link, though. When I do startx on the remote box it actually starts the WM on the remote machine!

I'm not sure it's possible to remotely run the entire x-server.

[lal]

Still haven't got a whole desktop running over the SSH link, though. When I do startx on the remote box it actually starts the WM on the remote machine!

Don't startx on the remote host!  The command I use on the local machine in a virtual console (Ctl-Alt-F1):

Code: [Select]

xinit /usr/bin/ssh -X remotehost /etc/X11/Xsession -- :1

where Xsession is a script on Debian-based distributions that starts everything needed for the default desktop environment.  Could be replaced by the WM of your choice I guess.

[ironcoder]

when I do that it starts a new X session on my box...as in I lose my current X session. When I ctrl-alt-bksp I get back my original X session. This isn't what I was hoping for!

[lal]

It starts an *additional* X server on the next unused virtual console, probably tty8.  You can switch between the two X servers with Ctl-Alt-F7 and Ctl-Alt-F8, or try all function keys if that doesn't work.