During the course of Homestuck, Jade Harley uses several computing devices to stay in touch with her co-players and the trolls.
Lunchtop
The Lunchtop is Jade's laptop computer, contained within a Squiddles lunchbox. The interface of Jade's computer is 3D holographic.
Jade's lunchtop was thrown free of her bedroom when it was destroyed.
Kanaya Maryam also owns a Lunchtop. However, Kanaya uses the lunchtop with the lid closed. Also of note is the fact that Kanaya's keyboard projection is tinted dark jade (pun obvious) while Jade's is a bright green (like Kanaya's lipstick).
The communications device used by John in the future uses the Lunchtop's holographic technology, as well as its general shape.
Jade combines the lunchtop with several items during her Alchemization spree post-Medium entry to make a variety of items that are all functional computers. Jade will never be caught without a computer, ever.
See Jade's outfits for how she's paired the accessories with her alchemized clothing.
Lunchmuffs
Stylish and functional.
Later on, John creates a similar device bearing the image of Bill Cosby. It is first seen with him right before he initiates the scratch.
Johnnytop
Finally, a difficult to use hands-on computing solution that does nothing but roll around of his own accord while talking about his emotions and reading books fast!
This computer is later destroyed by Eridan after the only time he contacts Jade.
Junior Compu-Sooth Spectagoggles
The über-expensive Junior Compu-Sooth Spectagoggles allow Jade to view anything that's going on in the entire Incipisphere. Totally worth it! Plus, you can never have too many cool computers.
A memory copy of these can be found in the chest near Mituna in part 3 of Openbound, implying that Jade has paid at least one visit to the A1 trolls.
Warm Fuzzy Squiddlejacket and Squiddlesneaks
The soft and stylish Squiddlejacket and the matching pair of Squiddlesneaks are BOTH computers. Seriously. You can never have too many computers.