Skyline runs on Windows 7 or later.
Skyline is tested nightly on 64-bit Windows 7 and 64-bit Windows 10. Most of our development is on Windows 10 (and 7), but we know of no reason Windows 8 and 8.1 shouldn't work.
We test the 32-bit Skyline build, but not regularly on a 32-bit OS, and < 10% of Skyline use is now 32-bit. We are likely to phase out 32-bit builds sometime in 2019.
Skyline 2.6 was the last version to support Windows XP. (All versions of Skyline since 1.4 can be downloaded from "Unplugged" installation pages by clicking "I Agree" and then the "Archive" link.)
There is no minimum requirement, but for performance reasons a large fast hard drive is desirable. The amount of memory needed depends on the size of your experiments, but 4GB is a good start. Skyline is frequently taught on relatively average modern laptops. But, for larger-scale processing we recommend a more powerful desktop system with dual 24-inch monitors to take full advantage of Skyline display capabilities.
We recommend modern i7 quad-core processors, running at 3.5 to 4.0 Ghz work well, with 16 to 64 GB of RAM and a fast SSD (e.g. 500 GB) + a spinning HD with more room (e.g. 2 TB).
A modern option as of June 2021 of the type favored by Skyline developers can be found on Amazon:
Dell XPS 8940 Tower Desktop Computer - 10th Gen Intel Core i7-10700 8-Core up to 4.80 GHz CPU, 64GB DDR4 RAM, 2TB SSD + 4TB Hard Drive
For really large-scale projects, like hundreds of DIA or DDA files with many hundreds of thousands of transitions, Skyline now makes effective use of highly multi-processor (NUMA) servers with 192+ GB of RAM. We have been using Dell PowerEdge R630 with 48 logical processors and 192 GB (spec attached - purchased for under $10,000 USD). For best import performance, use SkylineRunner command-line interface with --import-process-count=12 (or similar). Be sure to run tests. Mileage may vary depending on the import file format and disk drive type and speed.