Recently (less than one year ago) i bought an iMac 21,5".
Now i would like to use it as secondary monitor for my laptop. (My laptop runs Windows 7).
Is it possible? (I found conflicting opinions on the web, even on the Apple forum).
What type of cable do I need?
(I will appreciate also a link to the product on some online store: amazon, ebay etc.)
Thank you in advance.
UPDATE:
I tried air display… i'm not satisfied at all…
typical scenario: browser window on the main Windows laptop, dev tools/firebug on the secondary iMac screen.
The mouse goes fast between the 2 screens (GOOD), but when i changed the selected tab nothing happens. I had to drag the dev tools window to the main screen to get an update of the selected tab.
My test is ended here.
I'm still waiting for other answers.
I will prefer an answer that suggest me what kind of cable i've to buy, and where i can find it on the web.
Best Answer
Thunderbolt-equipped iMacs prior to iMac (Retina 5K, 27-inch, Late 2014) (see this document), like your iMac (Mid 2011), support Target Display mode:
Thunderbolt-only solution
NOTE: This won't work for iMac (Retina 5K, 27-inch, Late 2014) and later iMac models as they don't support Target Display Mode.
If you happen to own a laptop with a Thunderbolt port follow these simple steps to extend your display (Thunderbolt to Thunderbolt cable required) (from KB PH4469):
(As a side note: Older iMacs with Mini DisplayPort also support Target Display Mode. The steps to configure and enable Target Display mode are very similar.).
A comment on DVI to Thunderbolt adaptors
You can't use Mini DisplayPort to DVI or VGA adaptors:
to connect a computer with a DVI/VGA port to a Thunderbolt display (from this thread):
There is some hope, though, as the post goes on to say:
The poster is probably refering to a product mentioned earlier in the thread: the Kanex C247D Single-Link DVI to Mini DisplayPort Converter, advertised like this:
However, opinions diverge on whether it will work with a Thunderbolt display at all:
I've noticed that the LED Cinema Display is listed as a Mini DisplayPort display (from http://support.apple.com/kb/SP502):
so the adaptor may indeed only work with Mini DisplayPort displays, not with Thunderbolt displays, and as far as I can tell, your iMac will act like a Thunderbolt display.
It's up to you to try it, although $129.90 (as of this writing) is a steep price to pay for the Kanex adaptor just to test it.
Software-based solution
If the solutions described above aren't feasible or cost-effective, you can use several software solutions. One is Air Display:
There is a free trial version here.
Note: Windows 7 Starter edition is not supported.