Convex Computer the C-series vector computer, the Exemplar was a parallel-computing machine that used HP PA-7200 microprocessors, connected together using SCI. First dubbed MPP, these machines were later called SPP and Exemplar and sold under the SPP-1600 moniker. The expectation was that a software programming model for parallel computing could draw in customers. But the type of customers Convex attracted believed in Fortran and brute force rather than sophisticated technology. The operating system also had terrible performance problems which could not easily be fixed. Eventually, Convex established a working partnership with HP's hardware and software divisions. Initially it was intended that the
Compound refractive lens the order of meters, by using many lenses in series. To minimize the absorption the lens must be made from a material such as aluminium, beryllium, or lithium. CRLs were first demonstrated in the mid-1990s by a group of scientists at the ESRF. They drilled holes in an aluminium block, and achieved focusing in two dimensions. For X-rays a concave lens focuses the X-rays because the index of refraction is slightly below unity. In a CRL of this type the walls between the cylindrical holes act as concave lenses for X-rays traveling perpendicular to the axis of the drilled cylinders.