| 摘要 |
PURPOSE:To prevent the deterioration of performance when RAM breaks down by correcting a control storage by a microprogram read register. CONSTITUTION:One word in a micro program, which is addressed by a signal line 101 and is read from the control storage (CS) l is set in the microprogram read register (RD) 3 through a selector 4. When an error check circuit 5 detects a two-bits error, a flip flop 6 is set and the selector 4 selects a path from MM 2 and accesses a memory for reading correction data. The address of CS l where the two-bits error occurs is held in an address register (RA) 7 and accurate microprogram data which is obtained by converting the address into the address of a word concerned on a main storage device (MM) 2 so as to be read in an address conversion circuit 8 is set in RD 3 through the selector 4. Thus, the deterioration of performance when the fault occurs can be prevented. |
