On the Optimality of the Probability Ranking Scheme in Storage Applications
Journal of the ACM (JACM)
Permutation of data blocks in a bubble memory
Communications of the ACM
The Movement and Permutation of Columns in Magnetic Bubble Lattice Files
IEEE Transactions on Computers
The Generation of Permutations in Magnetic Bubble Memories
IEEE Transactions on Computers
On the Complexity of Sorting in Magnetic Bubble Memory Systems
IEEE Transactions on Computers
A Tree Storage Scheme for Magnetic Bubble Memories
IEEE Transactions on Computers
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In this paper we study the problem of permuting records in various simple models of magnetic bubble memories. Previous studies usually assumed the memory system either had one switch or n independently controlled switches, where n is the number of records to be permuted. In the former case, the time complexity to permute a set of n records is O(n2), while in the latter case, the time complexity is O(n). In this paper, we propose several simple models of bubble memory systems with their numbers of switches ranging between 1 and n and analyze the respective time complexities and respective numbers of control states for some permutation algorithms designed especially for them. Specifically, four models are studied: They have essentially log2n, 2√n, (log2n - log2log2 n)2, and k switches; their respective time complexities are essentially (3/2)n log2n, (5/2)n, (7/2)n and 2-1/k kn1+(1/k); and their respective numbers of control states are essentially 4 log2n, 2√n+1, 2n/log2n, and 4k.