I recently completed a roof project for a relative. This was roof #3 for the home- tore off the previous two layers. The home is about 40 years old with roof trusses and 1/2 (maybe 7/16) plywood sheathing, no clips. Plenty of roof and eave ventilation. As expected, the roof deck seemed to be quite brittle. A 220# guy with a bundle of shingles in hand could have stepped through the roof quite easily.
DSLR Definition: Digital Single Lens Reflex Camera. The Nikon D3000 is a DSLR camera. A DSLR, or digital single lens reflex camera is an advanced type of digital camera that provides high-level image quality, performance levels, and manual control options, typically much better than what you'd receive with a fixed lens camera.
Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access. DSL service can be delivered simultaneously with wired telephone service on the same telephone line.