Browse Prior Art Database

Data Processing Unit

IP.com Disclosure Number: IPCOM000091308D
Original Publication Date: 1968-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Hanson, NI: AUTHOR [+5]

Abstract

Where a computer system requires a core storage of high reliability and availability, a dual-write capability is usually provided using two like but separate storage units. The drawing shows how a data processing system, having two such storage units A and B operating on a shared basis, can be advantageously provided with the capability of manually-initiated, on-line transfer of data and storage protect keys from either shared storage unit to the other. Such are provided without requiring special programming,and without affecting computer processing operations except for normal shared storage delays.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Data Processing Unit

Where a computer system requires a core storage of high reliability and availability, a dual-write capability is usually provided using two like but separate storage units. The drawing shows how a data processing system, having two such storage units A and B operating on a shared basis, can be advantageously provided with the capability of manually-initiated, on-line transfer of data and storage protect keys from either shared storage unit to the other. Such are provided without requiring special programming,and without affecting computer processing operations except for normal shared storage delays. Such a capability permits either storage unit to be removed from the system either for maintenance or updating or both and then returned to the system without program interruption or lost processor availability to the other storage unit. Control of this on-line transfer capability is provided by transfer control unit TCU 10, used employed with an exemplary system employing two computer processing units CPU's 1 and 2 operating on a shared basis with respect to two storage units SU's A and B via lines 12 and 14.

In operating TCU 10, an operator first sets its manual controls for The particular transfer operation which is to be performed, that is, to indicate whether there is to be a transfer from SUA to SUB or vice versa. The storage unit from which data and storage protect keys are to be transferred is considered to be the primary storage unit. The other storage unit which is to receive the transferred data and storage protect keys is considered to be the secondary storage unit.

An operator manually initiates the on-line transfer operation, such as by depressing a push button. TCU 10 responds to this indication by first providing appropriate signals via lines 16 and 18 and the respective shared interfaces to cause the storage protect keys in the protect portion of the primary storage unit to be sequentially transferred to the protect portion of the secondary storage unit via the appropriate key bus 15 or 17, regardless of possible protect violations. TCU 10 then proceeds to provide appropriate signals via lines 16 and 18 and the respective shared interfaces to cause the transfer of data from the primary to the secondary storage unit via the appropriate data bus 22 or 24.

TCU 10 begins its operation by causing a fetch to be made to the primary storage protect lowest address as indicated by an appropriate one of address counters ACA and ACB. Where higher level storage protection exists, a first special signal is also provided by TCU 10 to insure that the key is regenerated in the protect portion of the primary storage unit. This key is gated to the protect portion of the secondary storage unit via key bus 15 or 17, depending on the direction of transfer, where a set key instruction is performed to store the transferred key at the lowest address of the prote...