Browse Prior Art Database

Data Migrated Device Emulator

IP.com Disclosure Number: IPCOM000088227D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Larson, LE: AUTHOR

Abstract

There are two environments possible when a new device/architecture is marketed, the new and the old. Generally the technique of handling the data involved during the time of migration is that of emulation, a technique of mapping an old environment to the new. Thus: (Image Omitted)

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Data Migrated Device Emulator

There are two environments possible when a new device/architecture is marketed, the new and the old. Generally the technique of handling the data involved during the time of migration is that of emulation, a technique of mapping an old environment to the new. Thus:

(Image Omitted)

However, the records created in the emulated environment historically could not be accessed in the native mode (either because of no software availability or specialized recording techniques). Thus the user was faced with an all or nothing situation (all emulated or all native). This disclosure modifies the mapping process so that the new record created can be accessed by standardized software operating in the native mode. Thus:

Now the user may have program applications in a partially converted state, some old and some native, as dictated by business considerations. An example of an implementation of this disclosure follows: 1) Assume the new device is a sectorized disk whose sectors are sequentially numbered, and individually accessed. 2) Assume the old device is a DASD (direct-access storage device) architecture device (e.g., the IBM 2314). 3) Assume that the native access to the new device is through the VSAM (virtual storage access method). 4) Then: a) A DASD record appears as

(Image Omitted)

b) The 2314 track would be simulated by a number of sectors to accommodate the amount of data that could be held on the 2314 track. This number of sectors would b...