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Single Line Decoder for Bubble Memories

IP.com Disclosure Number: IPCOM000078208D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 64K

Publishing Venue

IBM

Related People

Fox, JH: AUTHOR

Abstract

Fig. 1 shows a bubble domain memory system which uses a write and read decoder having a single control line flowing therethrough. In more detail, magnetic sheet 10 has located thereon a plurality of domain generators G1, G2, ..., G8. Current I(w) through loop 12 produces domains from each of the domain generators G1 - G8. Various propagation paths exist for each domain in the write decoder, generally indicated by numeral 14. Decoder 14 has a single decode line 16 which travels throughout the decoder. Depending upon the sequence of current pulses applied to line 16, a single domain will be allowed to pass from one of the generators G1 - G8 to an output channel 1, 2, ..., 8.

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Single Line Decoder for Bubble Memories

Fig. 1 shows a bubble domain memory system which uses a write and read decoder having a single control line flowing therethrough. In more detail, magnetic sheet 10 has located thereon a plurality of domain generators G1, G2,
..., G8. Current I(w) through loop 12 produces domains from each of the domain generators G1 - G8. Various propagation paths exist for each domain in the write decoder, generally indicated by numeral 14. Decoder 14 has a single decode line 16 which travels throughout the decoder. Depending upon the sequence of current pulses applied to line 16, a single domain will be allowed to pass from one of the generators G1 - G8 to an output channel 1, 2, ..., 8.

Fig. 2 shows a truth table for operation of decoder 14. When a current pulse is applied in decode line 16 at any time period T1, T2, ..., T6, the presence of a current will be indicated by numeral 1 in the truth table, while the absence of a current at any particular time T1, ..., T6 will be indicated by a 0. For instance, time T1 is the time in which domains from the generators get to the first intersection of conductor 16 with the T and I bar propagation paths. For each activation of decode line 16, 1/2 of the domains remaining from the generators G1 - G8 are destroyed. Consequently, by the time the domains reach the output end of the decoder only a single domain remains. For instance, the first row of the truth table of Fig. 2 shows that application of a current pulse on line 16 at times T2, T4 and T6 will destroy all domains except a single domain which exits into channel 1.

The single domain exiting from any channel goes to a programmable bubble generator (PBG 1, PBG 2, ...,PBG 8). This single domain becomes a "Mother" bubble on the appropriate PBG and is used to provide domains into the associated shift register SR for each rotation of the propagation field H. Fig. 3 shows the programmable bubble generators in more detail.

Information from the shift registers SR passes through read decoder 18, which is the same as write decoder 14. Depending upon the sequence of pulses applied to read decoder 18, information is read out of selected registers and is detected by the appropriate sensor S1, S2, ..., S8. After this, the information is destroyed by the appropriate annihilator A1b, A2b, ..., A8b. If desired,...