Modern operating systems would not be possible without the ability of a CPU to execute code at different privilege levels. This feature became available for mainstream PCs in the early eighties, when Intel introduced its 80286 and 80386 CPUs, and was readily employed by operating systems like Windows 3.11 and, of course, Linux, which Linus … Continue reading The protected mode in the x86 architecture
Month: December 2018
Navigating downhill: the quantum variational eigensolver
In quantum mechanics, the dynamics of a system is determined by its Hamiltonian, which is a hermitian operator acting on the Hilbert space that describes the system at hand. The eigenstates and eigenvalues of the Hamiltonian then correspond to stationary states and their energies, and finding these eigenstates and the corresponding eigenvalues is the central … Continue reading Navigating downhill: the quantum variational eigensolver
Into the quantum lab – first steps with IBMs Q experience
Even though physical implementations of quantum computers make considerable progress, it is not likely that you will have one of them under your desk in the next couple of years. Fortunately, some firms like IBM and Rigetti have decided to make some of their quantum devices available only so that you can play with them. … Continue reading Into the quantum lab – first steps with IBMs Q experience
Virtual memory
If you wanted a slogan that summarizes key trends in the IT industry over the last 30+ years, then "everything is virtual" would be a good candidate. In todays computing environments, essentially every physical resource is virtualized - and pretty much the first resource where this happened in mainstream computing was memory. In this post, … Continue reading Virtual memory