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Browse Prior Art Database

Automated Storage Management

IP.com Disclosure Number: IPCOM000082755D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 38K

Publishing Venue

IBM

Related People

Waguespack, LJ: AUTHOR

Abstract

Described is a technique for the managing of variable-sized units of real storage, while eliminating internal fragmentation and minimizing external fragmentation of storage. In implementing the described management scheme, for minimizing overhead, it is preferred that the required apparatus be local to a processor.

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Automated Storage Management

Described is a technique for the managing of variable-sized units of real storage, while eliminating internal fragmentation and minimizing external fragmentation of storage. In implementing the described management scheme, for minimizing overhead, it is preferred that the required apparatus be local to a processor.

Storage is virtually addressed via a content addressable memory (CAM) which contains virtual volume addresses and their respective real addresses for translation. A virtual volume (VV) exists when real storage has been allocated to it and an entry for it exists in a directory. A VV is completely described by its name, length attribute (N-LA), and contiguity status. The storage system is under control of a storage controller, which includes an availability vector map for allocation purposes. The vector map is a bit nap reflecting the allocation of storage elements (SE's), which are selected to be the optimal unit of real storage independent of the size of VV's.

Each VV consists of any number of SE's (that number less than or equal to the total number of SE's of real storage). The availability vector is preferably a high-speed circuit type memory, attached to a storage controller, and local to each processor. Maintainability of each vector is by single microinstructions, either in the processor or in the storage controller. Such instructions can DEFINE SPACE (desire to allocate real storage to a W ), SETON (the vector availability is turned off), SETOFF (the unit of storage is now available), and the like.

Allocation routines of the storage controller are driven by micro-routines called GRAB, ALLOCATE, and CHUCK. GR:AB locates and acquires contiguous free SE groups. ALLOCATE acquires SE's in either contiguous or noncontiguous groups. The routine automatically chains together non- contiguous sets. The CHUCK routine is the complement of ALLOCATE, i.e., deallocates or releases real storage. It is appreciated that other micro routines are necessary for updating directories, accessing data, and the like. Since these are rather obvious from the description, they are dispensed with.

In an execution environment, a typical superv...