The Logon Shaker has been developed for several years by Longshot while writing his Compendium. The aim was to precisely analyze the timings of the Amstrad CPC on as much bordeline cases as possible, thus making the most complete documentation ever about the CRTC6845, the Gate Array, Z80 and their interactions.
When the Compendium has been released, Longshot also gave his shaker away in order to help Amstrad CPC emulator developers to improve their programs. The Shakerland website displays more than 1500 pictures taken on a real CPC to show what is the result of each test. This way everyone could compare his favorite emulator's result to the real output provided by an Amstrad CPC.
Upon request of an emulator developer, a macro language named CSL (as well as a proposition for an automatic screenshot capability) has also been developed. This way emulators could launch the tests automatically, checking for non-regression.
The Shaker, CSL & the Compendium have been used during the development process of Amspirit.