METHOD AND APPARATUS FOR CONTINUOUS AFTER-IMAGING

摘要

A transactional data base processing apparatus which executes plural transactions causing a data base to be updated, incorporates an after-image recovery storage apparatus and method which enables continuous operation of the transaction system. The after-image recovery storage apparatus has a temporary storage file and a permanent storage file with circuitry for writing from the temporary storage file to the permanent storage file. That circuitry also writes after-image updating data records to the temporary storage file. The apparatus further includes elements for initiating transfer of the after-image data records from the temporary storage file to the permanent storage prior to a time when the temporary file is filled with the data records. The transfer is accomplished by operating the apparatus on a time shared basis so that other ongoing operations including transactional operations occur as the after-image data is being transferred to a permanent storage device.