A magnetic bubble domain flight recorder

An all electronic bubble memory system is aimed toward direct replacement of present flight tape recorders which have a high rate of failure due to the tape transport mechanism. A small 60k bit bubble recorder has been built to demonstrate the feasibility of this approach. It consists of six 10k bit chips mounted in three separate packages operating as a FIFO at 150 KHz bubble data rate. In addition to a FIFO the bubble recorder can be organized as a block oriented memory and also can be operated asynchronously to very low frequencies adding dimensions of flexibility and reliability not found in the present tape recorder system. Recorder nonvolatility is achieved by power shutdown protection circuits and a magnetically closed structure which also prevents magnetic contamination of surrounding equipment. A 10^-8detection error rate is achieved with a 300μV detector signal at 150 kHz using power strobing and d.c. restore. Projection on a 50M bit prototype recorder is made. A 10⁵bit chip capacity is proposed based on the electronic cost and MTBF considerations. This prototype operating at 150 kHz is capable of meeting or surpassing the capacity, data rate and reliability specifications of most present flight tape recorders.