Recovery of User Memory in an Electronic Typewriter During Power On/Off Cycles
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
When power is cycled during certain critical processes in an electronic typewriter having a memory, loss of the user document memory can occur. The possibility of this loss during a power cycle is reduced. In an electronic typewriter, certain processes cannot be interrupted due to loss of power without loss of the user document memory. For example, it is not possible to inhibit/prevent the Non-Maskable Interrupt (NMI) that occurs with a power line disturbance, such as when power is turned off or a cartridge is inserted or removed. To alert the user that a non-interruptible operation is in progress and that the machine should not be turned off, a WAIT annunciator is turned on, but the user sometimes still turns the machine off notwithstanding the WAIT annunciator being on.