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Memory Clear Indication for Electronic Typewriter

IP.com Disclosure Number: IPCOM000046454D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gerstle, PJ: AUTHOR [+3]

Abstract

For electronic typewriters which have volatile memory for storage of the user documents, it is necessary to indicate whether power has been interrupted to that memory in such a way as to cause partial or complete loss of the contents thereof.

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Memory Clear Indication for Electronic Typewriter

For electronic typewriters which have volatile memory for storage of the user documents, it is necessary to indicate whether power has been interrupted to that memory in such a way as to cause partial or complete loss of the contents thereof.

When an operator stores a document in the user memory, it may remain in the memory for an extended period of time, several days or weeks, prior to being purged. Should the power be interrupted to the memory, the data stored therein will be either destroyed or become unusable due to errors introduced by such power loss.

In order to indicate to the operator that the power has been interrupted to the memory, a software routine may be incorporated into the non-volatile ROS (read- only store) of the processor system to perform a check of the RAM (random- access memory) used for the storage of documents. In the event that the power has not been interrupted, four selected but scattered locations in the RAM are compared with a standard value, and if all of the four values stored in the four scattered locations correspond with the preselected standard value, then it is assumed that power has not been interrupted and that the memory contents are in fact correct.

In the event that the values in each of the four locations do not correspond exactly to the previously predetermined standard value, then it is assumed that the memory has been rendered unreliable by virtue of a power interrupt...