Virtual desktops versus multiple monitors

A commentator here asked:

With respect to tabs vs. windows (vs. virtual desktops vs. extra monitors vs. separate computers), I always wonder what combination of the above will lead to the greatest productivity.

Having used both, my personal opinion is that virtual desktops are inferior to multiple monitors for the same reason that tabs are inferior to windows, namely that you can't see two virtual desktops at once. This makes virtual desktops good for grouping and a good place to shove excess windows but not a good solution when you really need to see that many things at once.

(Although I'd used virtual desktops for years, even a casual experiment with dual monitors was such a powerful experience that I was hooked on the spot. But I continue to use virtual desktops even with multiple monitors; you can never have enough space, and as mentioned I'm very big on using spatial organization for things, which virtual desktops are good for. Plus, for a sysadmin the ability to instantly get an uncluttered workspace to deal with some important interruption is very useful.)

I'd think that a single computer with multiple monitors is better than several computers, each with a single monitor, for much the same reason; using separate computers with separate displays constrains how you organize and re-organize information. The exception is if you really need multiple computers for some reason (a classic reason being testing on one machine and debugging from the second), in which case you have no choice.

Sidebar: the poor man's KVM

If you have a primary machine plus one or two secondary machines that you only use occasionally and modern LCDs with both VGA and DVI inputs, you can construct what I call a 'poor man's KVM':

• give each machine its own keyboard and mouse, ideally small ones for everything except your primary machine
• hook your primary machine up to one set of inputs (DVI or VGA) on the LCD panels.
• hook the secondary machine(s) up to the other LCD panel inputs

When you want to use a secondary machine, pull out its keyboard and mouse and switch the appropriate LCD monitor's input to it. (If you don't need to watch anything on the primary machine, you may want to power off the other monitor to avoid absent-minded mistakes.)

It's probably easier to put the primary machine on the DVI inputs and the secondary machine or machines on VGA (partly because more things still support VGA than support DVI).