Means and methods for preserving microprocessor memory

A system for preserving at least the main random access memory ("RAM") of a computer system having a power supply on the occasion of a sudden loss in power, said system comprising:

• a power loss detection circuit adapted to sense a loss in the power supply of said computer system and emit a signal causing a switch-over circuit to isolate at least said main RAM from the computer system and cause at least said main RAM to receive its power from an independent power source;
• and
• a power switch-over circuit responsive to said power loss detection signal to connect said independent power source to said memory;
• and
• an independent power supply comprising an external transformer power supply, a rechargeable battery, a voltage regulator, and a battery charging circuit connected to said battery, said transformer power supply being connected to said voltage regulator and to said battery charging circuit, said battery being connected to said voltage regulator for delivery of power to said switch-over circuit;
• and
• a power-fall detection circuit comprising a precision voltage reference, means for measuring the input voltage to said computer system, and a comparator for initiating an NMI alert signal when said measured input voltage falls below said precision voltage reference;
• and
• software operatively associated therewith and responsive to said power loss detection circuit signal to initiate a shutdown routine when said signal is activated and to initiate a restart routine when said signal is deactivated;
• and
• security means for interrupting a normal startup sequence of said computer system to invoke a security procedure, whereby further use of said computer system would be allowed only after identifying an authorized user.