Abstract: Two-terminal memory can be configured as multi-level cell (MLC) memory in which a single memory cell can represent multiple bits of information. Unlike certain other memories that are subject to disturb errors, for the disclosed two-terminal memory, these multiple bits can store information that is included in the same logical page of memory, which can be advantageous. However, performing error-code correction (ECC) operations on multiple bits of data from the same MLC can result in additional stress on an ECC engine because if a MLC fails, all bits of that cell are likely to be bad. Splitting the multiple bits of a MLC in connection with encoding or decoding can average the errors from bad cells across multiple ECC codewords, thereby providing better coverage with the same ECC or reducing the overhead associated with ECC coverage.

Abstract: A method and apparatus for marking a block of multi-level memory cells for performance of a block management function by programming at least one bit in a lower page of the memory cell block such that a first logic state is stored in the at least one bit in the lower page; programming at least one bit in an upper page of the memory cell block such that the first logic state is stored in the at least one bit in the upper page; reprogramming the at least one bit in the upper page such that the at least one bit transitions from the first logic state to a second logic state; identifying the first logic state in the at least one bit of a lower page and the transition of at least one corresponding bit in the upper page from the first logic state to the second logic state; and in response, marking the corresponding memory cell block for performance of a block management function.

Abstract: A method and apparatus for marking a block of multi-level memory cells for performance of a block management function by programming at least one bit in a lower page of the memory cell block such that a first logic state is stored in the at least one bit in the lower page; programming at least one bit in an upper page of the memory cell block such that the first logic state is stored in the at least one bit in the upper page; reprogramming the at least one bit in the upper page such that the at least one bit transitions from the first logic state to a second logic state; identifying the first logic state in the at least one bit of a lower page and the transition of at least one corresponding bit in the upper page from the first logic state to the second logic state; and in response, marking the corresponding memory cell block for performance of a block management function.

Abstract: A method and apparatus for marking a block of multi-level memory cells for performance of a block management function by programming at least one bit in a lower page of the memory cell block such that a first logic state is stored in the at least one bit in the lower page; programming at least one bit in an upper page of the memory cell block such that the first logic state is stored in the at least one bit in the upper page; reprogramming the at least one bit in the upper page such that the at least one bit transitions from the first logic state to a second logic state; identifying the first logic state in the at least one bit of a lower page and the transition of at least one corresponding bit in the upper page from the first logic state to the second logic state; and in response, marking the corresponding memory cell block for performance of a block management function.

Abstract: A method and apparatus for programming one or more bits in an upper page twice depending on the value in a corresponding bit in a corresponding lower page in a multi-level cell device. The method includes the steps of initializing the bit in the lower page and the bit in the upper page by storing a value of one in each of the bits. One or more bits in the lower page are then programmed such that a one is stored in the one or more bits of the lower page. One or more bits in the upper page are then programmed such that a one is stored in the one or more bits of the upper page. The one or more bits in the upper page are then reprogrammed such that the value in the one or more bits of the upper page transitions from a one to a zero. The transition from a one to a zero in the one or more bits of the upper page is used to mark for performance of a block management function the block.

Abstract: The invention relates to a method for precipitating mono or multiple layers of organophosphoric acids of the general formula I (A) Y—B—OPO3H2??(IA) or of organophosphonic acids of the general formula I (B) Y—B—PO3H2??(IB) and the salts thereof, wherein B is an alkyl, alkenyl, alkinyl, aryl, aralkyl, hetaryl or hetarylalkyl residue and Y is hydrogen or a functional group from the hydroxy, carboxy, amino, optionally low-alkyl-substituted mono or dialkylamino series, thiol, or a negative acid group from the ester, phosphate, phosphonate, sulfate, sulfonate, maleimide, succinimydyl, epoxy, acrylate series, wherein a biological, biochemical or synthetic indicator element may be coupled to B or Y by addition or substitution reaction, wherein compounds may also be added conferring the substrate surface a resistance to protein adsorption and/or to cell adhesion and in the B chain may optionally be comprised one or more ethylene oxide groups, rather than one or more —CH2— groups.

Abstract: A disk recording/reproduction device according to the present invention includes: a recording medium including a disk and a protective case for the disk; loading mechanism for guiding the recording medium from a first position outside the disk recording/reproduction device in a first direction in a linear manner, then to a second position located inside the disk recording/reproduction device, and thereafter in a second direction perpendicular to the first direction to a third position, the first position allowing the recording medium to be taken out and the third position allowing information to be recorded on the recording medium; a pickup; a pickup driving mechanism for moving the pickup in parallel to a recording face of the disk; a magnetic head opposing the pickup so as to interpose the disk and moving in parallel to the disk integrally with the pickup; and head position switching mechanism for detaching the magnetic head from the disk and positioning the magnetic head in either a recordable position or

Abstract: A duplicator in a magnetic bubble memory with non-implanted patterns, a process for realizing the duplicator and a serial - parallel magnetic bubble memory having at least one of the aforementioned duplicators are disclosed. In a magnetic bubble memory having a first group of aligned non-implanted patterns and a second group of aligned non-implanted patterns, the duplicator according to the invention is characterized in that it comprises an extension conductor and a breaking conductor, the extension conductor linking the first and second groups of patterns, the breaking conductor being positioned transversely with respect to the extension conductor, the geometry of the end pattern of the first group of patterns being such that the duplication position is a stable position and the geometry of the patterns of the second group adjacent the axis of the first group being such that the reception position of the duplicated bubble is a stable position.

Abstract: In a magnetic bubble memory device in which a major line and minor loops are constituted by ion-implanted tracks, a gate is constituted having two functions, i.e., having a replicate function and a pseudo swap function using conductor patterns of two layers that overlap on both the major line and on the minor loops. By controlling the pulsed current supplied to the conductor patterns of the two layers, the replicate function divides the bubble in the minor loop into two bubbles, so that one of the bubbles is taken onto the major line and is propagated to the detector. The pseudo swap function annihilates the bubble in the minor loop, divides the bubble on the major line into two bubbles and introduces one of them into the minor loop, thereby to realize the same function as that of the conventional swap gate.

Abstract: A bubble generator for use in a bubble memory device combines a nucleating generator and replicating generator in a unified structure with first and second hairpins disposed at respective first and second regions to define nucleation and replication sites. The conductor layer is configured such that the same polarity of current flow causes magnetic fields of opposite sense at the nucleation and replication sites. The nucleation site is used only to generate the seed bubble required at the replication site. Once the seed bubble is present, the replication site is utilized to produce the data stream. The nucleation and replication sites are preferably spaced apart with a propagation track extending from the former to the latter, and the first and second hairpins are series-connected with the series connection crossing the propagation path. The hairpins are preferably directed oppositely so that when the rotating field is in the right phase for replication, it is 180.degree. out of phase for nucleation.

Abstract: Bubble-to-bubble interaction in a magnetic bubble domain memory is reduced by a notch provided in the outer edge of the replicator of the bubble memory device. The notch serves to slow down the movement of the bubble around the replicator or U-turn element so that it does not elongate under a critical phase of the in-plane field.

Abstract: A magnetic bubble memory device comprises minor loops for the storage of information and a major loop operably associated with the minor loops through gates, the minor loops being defined by an ion-implanted pattern and the gate portions of the major line being defined by patterns of magnetically soft material. This construction makes it possible to provide a high storage density and superior gate operating margins.

Abstract: In a magnetic bubble replicator having a soft magnetic material element for propagating a magnetic bubble along an edge thereof in response to a change in a direction of an external magnetic field and a hairpin-shaped conductor superimposed on the soft magnetic material element, an angle between a slit of the conductor and a propagation path of the magnetic bubble of the soft magnetic material element is set to no less than 90 degrees, preferably 5-85 degrees, and more preferably to 45-60 degrees.

Abstract: The invention relates to a magnetic bubble memory having a first layer of monocrystalline magnetic material with at least one crystallographic axis having the property of being aplanar easy magnetization axis, whereby the first layer has groups of unimplanted, contiguous and aligned motifs, called first motifs, permitting the propagation of the bubbles into a second magnetic layer, positioned below the first magnetic layer, the first motifs being shaped in such a way that two cavities are defined between two first adjacent motifs, wherein each group of first motifs has an axis such that the first motifs of the group are arranged symmetrically with respect to the axis, the groups being arranged parallel to the crystallographic axis of the first layer of material, and wherein it comprises, associated with each group, an electrical conductor, called the first conductor, permitting the duplication of the bubbles, each conductor being arranged perpendicular to the crystallographic axis of the first layer of materi

Abstract: A magnetic bubble memory device is disclosed in which a magnetic bubble propagation circuit for forming a minor loop is formed by ion implantation, and at least part of a major line or major loop and at least part of connecting portions between the minor loop and the major line or major loop are formed of a film of a soft magnetic material.

Abstract: A magnetic bubble store, using adjoining non-implanted motifs as bubble-propagating motifs, the store comprising 3n identical, electrically interconnected storage devices, n being a positive integer, which are produced on an identical circuit chip and each comprise minor loops for storing the bubbles, at least one major loop acting as an access loop for the minor loops, first electrical component enabling bubbles to be transferred from the minor loops to the major loop and vice versa, a second electrical component enabling bubbles to be produced on the major loop, and a third electrical component enabling the bubbles on the major loop to be detected, the third, identical component, each formed by an electric conductor for bubble extension and contraction and a magneto-resistive element, being disposed in directions making an angle of 120.degree. with one another.

Abstract: A magnetic bubble memory has a plurality of minor loops for storing data represented by magnetic bubble sequences, a write line for transferring write data to couple them to the minor loops and a read line for transferring read data to a bubble detector. The read line is coupled to a plurality of auxiliary loops through replicators and the auxiliary loops are coupled to the minor loops through replicators. The data replicated to the auxiliary loops are read out.

Abstract: A magnetic bubble memory device has a plurality of memory loops which comprise minor loops and a map loop arranged independently of the minor loops. The map loop stores index data and parameter data of the memory chip. By detecting the index data, parameter data addresses are designated, and required parameter data are read out and stored in parameter memories, respectively, so as to allow operation of magnetic bubble memory chips having different storage capacities and different parameters under control of a single control circuit.

Abstract: A magnetic bubble memory system controller is provided to interface a user system and a magnetic domain chip. The controller will functionally accept commands from a user system and deliver those same commands to the appropriate devices associated with the magnetic bubble memory. A further function of the controller device will be to enable multipage read and write functions within the major loop of a magnetic bubble memory chip organization.

Abstract: A nucleation type magnetic bubble generator according to this invention has a conductor loop which consists of a hairpin portion and wiring portions. Moreover, the relationship of W.ltoreq.3/4 P holds between the width W of each wiring portion and the period P of a propagation path. As a result, the generation of an extra magnetic bubble can be suppressed, so that a magnetic bubble generator of wide current margin can be provided.

Abstract: A magnetic bubble domain memory device is provided that includes a magnetic bubble domain data chip having a major/minor loop organization in which one or more defective minor loops may be tolerated. Information in the form of a redundancy map is stored within the plurality of minor loops in a single page thereof, where a page is defined as one bit of information from the same virtual position on each of the plurality of minor loops. This redundancy map comprises firmware wherein the presence of a magnetic bubble domain within the designated page at a specified bit position identifies the particular minor loop corresponding to that bit position as a good loop, and conversely the absence of a bubble within the page at a specified bit position identifies the particular minor loop corresponding to that bit position as a defective loop.

Abstract: A detector for magnetic bubble domain devices including an input path for receiving and propagating magnetic bubble domains, an expander device which intersects the input path and functions to expand the bubble domain in a first direction, and a replication device which intersects the expander and functions to cut the expanded bubble into a plurality of magnetic bubble domains and to expand the bubble domain in a second direction. A plurality of detector strips are disposed along the second direction functioning to detect the plurality of magnetic bubble domains.

Abstract: A magnetic bubble memory device includes: a magnetic layer with a first region having an easy axis of magnetization extending in a certain direction and a second region surrounding the first region and having an easy axis of magnetization substantially perpendicular to that of the first region, said first region defining a plurality of bubble propagation patterns; and a replicate gate with a stretch conductor pattern, to which an electric current is applied so as to stretch a bubble between said propagation patterns, and a cutting pattern formed in the second region between the propagation patterns and adapted to lower the bubble collapse field so as to cut the stretched domain. The replicate gate is operated by applying an operating current pulse to the stretch conductor pattern, said operating pulse including a stretch pulse for stretching the bubble and a cut pulse, following the stretch pulse, for cutting the stretched domain.

Abstract: A replicator for an ion-implanted magnetic bubble domain device including a single level conductor bubble cutting element disposed between first and second spaced apart bubble domain guide structures. The charged wall movement in response to the rotating in-plane field functions to stretch a bubble domain travelling along the first bubble propagation path onto the second bubble propagation path and the conductor element crossing the stretched domain functions in response to an activating signal on the conductor to cut the bubble.

Abstract: A passive replicator for bubble devices receives a bubble from an input channel and splits that bubble into two bubbles which go into two separate output channels when a rotating magnetic field is applied. The bubble replicator is a single element which has at least three peripheral areas in spaced relation that are associated with different propagation channels. In preferred embodiments, an elongated bar is present in the propagation channels and it is positioned adjacent to and in spaced relation with a peripheral area of the replicator.

Abstract: A bubble domain replicator for ion-implanted contiguous disk devices has a cusp portion and a tip portion extending substantially away from the cusp portion so that the cusp forms part of a super track and the tip forms part of a bad track. A hairpin conductor is positioned over the cusp portion and tip portion so that the closed end of the hairpin is closest to and surrounds the end of the tip portion.

Abstract: A magnetic bubble domain swap gate circuit (28) for use with a magnetic bubble element having an information transmission line along which magnetic bubble domains are transferred and an information storage loop in which magnetic bubble domains are stored, wherein a magnetic bubble domain in the information transmission line can be transmitted to the information storage loop and a magnetic bubble domain in the information storage loop can be simultaneously transmitted to the information transmission line. The repetition period of the magnetic substance patterns which form the information transmission line, is greater than the period of the magnetic substance patterns forming the information storage loop.

Abstract: A replicator for a magnetic bubble domain device including a hairpin loop conductor element traversing first and second spaced apart bubble domain guide structures. The replicator functions to replicate a bubble domain travelling along the first bubble propagation path onto the second bubble propagation path in response to an activating signal on the conductor. The replicate guide structure includes two attractive cusp positions and one repulsive cusp position, so that the repulsive charged wall formed at the repulsive cusp position functions to sever a stretched bubble domain formed by the activating signal.

Abstract: A major/minor loop bubble memory system architecture includes a passive replicator in the major loop read channel which is connected by a first path to a mode switch-annihilator and a merge point in the major loop write channel and by a second path to an off-chip decision-making means and the merge point in the write channel. The decision-making means is positioned the same or fewer propagation steps than the mode switch-annihilator is from the replicator. The decision making means is activated to cause either the replicated data to pass through the mode switch-annihilator into the write channel or the replicated data to be annihilated in the mode switch-annihilator and the data from a generator to pass into the write channel.

Abstract: Replication in a magnetic bubble device is realized by a method of operation that is based on the principle of stretching, then cutting the bubble by the control current pulses. In this mode of operation, the bubble is stretched, under the influence of a large amplitude current pulse in the control conductor, between the switch propagate element in the primary track and another propagate element in the secondary track. The bubble strip is let to propagate for a fraction of a field cycle after which a second large amplitude narrow pulse is applied to the control conductor to sever the bubble strip into two parts. One part propagates as would the original bubble in the primary track and the second part propagates in the secondary track.

Abstract: A magnetic bubble memory device having a bubble generator which generates a magnetic bubble by conducting a pulse current on its hairpin-shaped conductor loop and a major propagation circuit for propagating the magnetic bubble to a transfer-in gate circuit which transfers the magnetic bubble to a memory storage region, wherein the device further comprises a gate means provided between the bubble generator and the major propagation circuit for transferring a magnetic bubble carrying information "1" onto the major propagation circuit at a first predetermined timing and preventing a spurious bubble to be transferred to the major propagation circuit at a second predetermined timing.

Abstract: A magnetic bubble domain device including a segmented stretcher detector. The detector is formed from a propagation path for magnetic bubble domains, and a first replicator disposed adjacent the propagation path. The first replicator functions to replicate one of the propagating bubble domains into a pair of magnetic bubble domains, and to transfer one of the bubble domains into a first secondary track extending in a direction different from the direction of the propagation path. A second replicator is disposed along the propagation path and functions to replicate the one bubble domain into a pair of magnetic bubble domains and to transfer one of the bubble domains into a second secondary track extending generally in the first direction. Finally, the detector is disposed along the first direction and functions to detect the plurality of magnetic bubble domains.

Abstract: A bubble memory chip includes a plurality of data loops, some of which may be defective, for storing magnetic bubbles representative of data therein. A serial-parallel input propagation path and a parallel-serial output propagation path are provided for propagating bubbles to and from the data loops. A plurality of spaced apart permalloy disk elements are provided, each adapted for having a single bubble circulated thereabout in the presence of an in-plane rotating magnetic drive field. A stream of bubbles representative of an error map indicating which of the data loops are defective is loaded onto and read from the disk elements to initialize the memory. A plurality of gates permit the bubbles of the error map to be transferred between an error map propagation path and the disk elements in parallel fashion upon pulsing of an adjacent control conductor. The potential for data scrambling in the error map is eliminated.

Abstract: Disclosed is a bubble memory having a plurality of data loops, some of which may be defective, and first input and output paths for propagating magnetic bubbles to and from the data loops, respectively. The memory further includes a plurality of redundant loops, and second input and output paths for propagating magnetic bubbles to and from the redundant loops, respectively. A pair of bubble generators are provided for simultaneously generating the same input data stream on both the first and second input paths. By selectively disabling certain first transfer gates associated with the data loops magnetic bubbles are prevented from being transferred into defective ones of the data loops. By selectively enabling certain second transfer gates and certain second replicate gates, magnetic bubbles representing the same information as those not transferred into the data loops can be stored and retrieved from the redundant loops.

Abstract: A magnetic bubble memory device according to this invention comprises a plurality of minor loops, a read-out major line is disposed at one end of the minor loops through gates having a replicating function, and a magnetic bubble detector which includes a detecting line is disposed at one end of the major line. Further, a propagation length from the other end of the read-out major line to the detecting line of the magnetic bubble detector is set at a bit length which slightly exceeds four times the number of the minor loops. For this reason, a continuous read-out operation at high speed is permitted without the influence of replicate pulses.

Abstract: A magnetic bubble memory chip is arranged in such a way that the major surface of the chip will not cross perpendicularly with the external bias magnetic field to generate a component of the bias magnetic field which is parallel to the major surface. This component is added to the rotating magnetic field within the chip major surface and the intensity of a resultant rotating magnetic field is shifted to the start/stop direction of this rotating magnetic field. Of the basic elements incorporated in the chip, the basic elements which operate stably in a comparatively intense rotating field is operated in synchronism with the phase of the start/stop direction of the rotating magnetic field in order to ensure stable operation of all the basic elements under the decreased intensity of the external rotating magnetic field.

Abstract: A magnetic bubble memory chip structure on which a plurality of magnetic bubble storage loops are provided for containing information data as represented by bubbles and voids and including a dedicated area on the chip for containing redundancy data as represented by a chain of bubbles and voids arranged in a predetermined manner to identify good and defective information data storage loops. The redundancy data-containing dedicated area of the chip comprises a plurality of redundancy data-containing storage loops of equal number to the information data-containing storage loops so as to correspond thereto in a one-on-one relationship, with the number of individual bit positions included in each information data-containing storage loop being significantly greater than the number of bit positions included in each individual redundancy data-containing storage loop.

Abstract: A magnetic bubble replication and transfer arrangement is disclosed which provides for replicating magnetic bubbles in thin planar layers of magnetic material without the need for electrical current carrying conductor elements. The arrangement includes a replicating half-disc permalloy element disposed in a particular way between first and second tracks formed from half-disc elements which are deposited on a surface of the magnetic layer. When a rotating magnetic field in the plane of the material is rotated in a predetermined direction with respect to the above arrangement, replication of a bubble in the first track occurs at a replication region where a portion of the replicating element is adjacent the first track. The original bubble continues movement within the first track while the newly formed bubble moves along the replicating element into the second track in response to rotation of the in-plane magnetic field.

Abstract: A magnetic bubble domain memory device is provided that includes a magnetic domain data chip having a major-minor loop organization with on-chip firmware providing redundancy information enabling the use of the chip even though one or more defective minor loops may be present thereon. One of the pages is written in the minor loop, where a page is defined as a common bit position in each of the plurality of minor loops, with a series of magnetic domains having an odd total number. The next succeeding page in the minor loops contains a series of magnetic domains and voids which are representative of the loop numbers of defective minor loops on the chip with the remaining pages in the minor loops having an even number of magnetic domains contained in each of the pages. Collectively, the pages containing the odd and even number of magnetic domains together with the page containing the map of the defective minor loops comprise the on-chip firmware providing redundancy information.

Abstract: An active replicate/transfer magnetic bubble domain switch which is especially compatible with gap tolerant structures is provided. The switch includes a broadfaced corner element of relatively massive structure which retains the bubble domain for more than one field cycle. The switch characteristics are superior to those of existing switches both at the 8 .mu.m and 16 .mu.m periods. The switch offers the advantages of good bias and phase margins, ease of fabrication and reduced drive field requirements. In the 8 .mu.m, version the device requires a substantially lower drive field than the pickax design by virtue of reduced bubble-bubble interaction in the minor loops.

Abstract: The magnetic bubble memory device of this invention is arranged such that a magnetic bubble detector and a nucleation type magnetic bubble generator in a chip are made to operate at different phases of the same operation cycle of a rotating magnetic field. Therefore, the operation time of the magnetic bubble detector and the operation time of the nucleation type magnetic bubble detector are completely separated from each other, although they are involved by the same cycle of operation of the rotating magnetic field. Consequently, the magnetic bubble detector can perform the detecting operation, without being affected by large amounts of noise which are generated during the operation of the nucleation type magnetic bubble generator.

Abstract: A magnetic bubble memory device according to this invention is characterized in that an electrical conductor which supplies a current pulse for driving gates having a replicating function is divided into a plurality of parts. The divided parts are connected to current pulse generator means in a mutually parallel relationship. As the current pulse generator means, accordingly, a pulse driver circuit whose output is a low voltage can be used. As a result, the cost of the pulse driver circuit is low.

Abstract: An improved magnetic domain generator for a magnetic arrangement employing a layer of garnet in which single wall domains (bubbles) are moved by an in-plane rotating magnetic field. A first domain generator includes a first propagation circuit for moving bubbles away from the generator when the rotating field is in a first direction. A second domain generator includes a second propagation circuit for moving bubbles away from the second generator when the rotating magnetic field is in an opposite direction to the first direction. The two generators are coupled to a common pulse source which is able to provide pulses at twice the rate of rotation of the magnetic field. In this manner, two independent streams of bubbles may be produced by the generators from a single pulse source.

Abstract: A block replicate bubble memory device is provided with a plurality of series storage loops, wherein data words are written into or read out of the storage loops in parallel. The data is entered into write lines and is read on to read lines which are connected to the series storage loops approximately one-half of one loop time apart. Information in the storage loops is ordinarily changed or altered in no less than one-half of one loop time in the prior art. The present invention provides a plurality of bubble generators connected to the serial write line in a manner which permits several bubble device functions to be conducted in less than one-half of one loop time.

Abstract: A magnetic bubble memory device which comprises special minor loops for storing address information regarding spare minor loops corresponding to defective regular minor loops. The structure of the bubble transfer or reproducing gates corresponding to said special minor loops is different from that corresponding to ordinary minor loops.

Abstract: A replicator for an ion-implanted magnetic bubble memory includes an offset hairpin geometry. The conductor is associated with features in adjacent bubble paths which exhibit strong attracting poles at the same time. The conductor stretches the bubble between the attracting poles. The bubble is severed by the reorienting propagation field.

Abstract: The familiar G-shaped, non-closed, major path in a major-minor, magnetic bubble memory is formed controllably into a closed circumferential major loop about the minor loops during operation. A simple data format allows a simple start-up algorithm to ensure that data are secured.

Abstract: A magnetic bubble domain chip having two levels of metallurgy fabricated in a single masking step and including a replicate type bubble generator. The bubble generator includes a magnetic disk which holds a seed domain during reorientation of a magnetic drive field in the plane of the magnetic bubble material, and a conductor located at the leading, i.e., cutting, edge of the magnetic disk. Current in the conductor is used to assist the splitting operation whereby a new domain is split from the stretched seed domain. The conductor includes a first portion having a relatively wide cross-section where most of the current flows through a highly conductive material, such as gold. In the area of the generator, the conductor is narrow and the current path is through the magnetic material comprising the disk.

Abstract: Disclosed is a magnetic bubble memory that includes a plurality of minor loops for storing bubbles representative of data therein, and a pair of minor loops for storing bubbles representative of an error map therein. The error map is selectively written into and read from only one loop of the pair. The other loop is redundant and improves chip yield. A serial-parallel bubble propagation path connects all of the loops to a bubble generator. This path includes a predetermined number of bubble propagation elements between the transfer-in gates for the pair of loops. Proper choice of the number of propagation elements enables the error map to be selectively written into/read from only one loop of the pair with only a single control line.

Abstract: A magnetic bubble domain chip layout or organization which achieves consecutive bit access is provided by arranging the device in two substantially identical halves or parts. Each half contains half of the total number of storage loops, a separate access loop with its own generator, switches between the storage loop and an access loop, and a separate detector. The separate detectors are connected together to form two arms of a single bridge wherein consecutive bit output is achieved. The generators in each half of the device are located at different distances from the switches between the loops in one half of the device and the associated access loop. In addition, each of the detectors is located a different distance from the switches in the respective halves or parts of the device.