| 摘要 |
PURPOSE:To improve an index system for a floppy disc device, by reading data of a fixed region and a stand-by region in the block and by reading data from an overflow part only when information indicating that overflowed data is present is recorded in a flag. CONSTITUTION:Index part I has only pointer PD for the access to data part D, and data part D consists of B1-Bn, and respective blocks have key words K1-kn, flags F1-Fn, and stand-by regions A1-An. In case that blocks B1, B2...Bn are accessed by pointer PD to read data in blocks, read data of block B2 becomes (data of fixed region)+(data of stand-by region)+(data d2) when only the signal of flag F2 is ''1''. This data d2 is written in overflow part A0 beyond stand-by region A2, and the case of this write is rare, so that this system is very adapted to the index system of the floppy disc device of slow access. |
