JPS6442728A - Writing circuit for magnetic disk device - Google Patents

Abstract

PURPOSE:To make it unnecessary to write again all data of a faulty magnetic disk device to a normal magnetic disk device, by writing a data to which a device number is added, to other normal magnetic disk device, and reading it out after a fault is released. CONSTITUTION:A data delay circuit 1 delays a write use data signal sent out of a host device, and an address memory circuit 2 stores a signal (b) which is sent out of the host device and shows a device number of a magnetic disk device. Also, a shift register circuit 3 converts an output signal (e) of the address memory circuit to a series signal (k), a data switching circuit 4 switches an output signal l of the data delay circuit and the output signal (k) of the shift register circuit, and a control circuit 5 controls the data delay circuit, the address memory circuit, the shift register circuit and the data switching circuit. Accordingly, even if one magnetic disk device fails, only the remaining data can be written to a normal disk device, therefore, when the fault is released, this written data is read out and re-written. In such a way, all the data can be made effective without executing rewrite of all the data.