In the 2.4 scheduler, the timeslice recalculation algorithm requires that all processes exhaust their timeslice before their new timeslices can be recomputed.

Middle node law among them give and publish detailed mathematics prove, exhaust and search for law give and produce the concrete algorithm.

To aim at the problem that the key space of DES is too small to prevent exhaust attacks, an expanding key space method is proposed and a chaotic transformed DES algorithm is constructed.