Data Organization in Magnetic Bubble Lattice Files

In this paper, we discuss several aspects of data organization in the framework of a recently developed magnetic bubble memory technology known as a bubble lattice file. A dynamic ordering scheme, different from those implemented in conventional T-I bar bubble memories, is proposed. This ordering is particularly suited for bubble lattices. Some performance figures are included for comparison. Introduction In the past few years, magnetic bubble memories have become increasingly important due to their potential for nonvolatile, large capacity storage. In addition to having an access time that is two orders of magnitude faster than the moving head disk, the bubble memory has features that can lead to simpler designs in controlling softwarelhardware and also to more sophisticated methods of data organization. Although there is a large body of literature (see, e.g., [ 11) on techniques for making bubble memories faster, cheaper, and higher in density, there has been relatively little discussion of bubble memory data organizations. (For some work in this area, see [281.) Furthermore, most of the discussions are restricted to T-I bar bubble memories. In this paper, we examine bubble memories in the light of bubble lattices, which promise much higher density than the traditional T-I bar technology [ 13. O u r purpose is to contrast the features of bubble lattices with other storage devices and suggest ways to make use of these features. Figure 1 Conventional BLF