Patent EP0071002A2 successfully refreshed from Google Patents.
EP0071002A2
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Data processing apparatus including stored value access control to shared storage
Assignee: International Business Machines Corp
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Filing: 1982-06-02
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Granted: —
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Expires: 2002-06-02
Abstract
Abstract A volatile memory 10 is shared by a plurality of using Units 11 in a loosely-coupled manner. A token area of the memory stores a predetermined bit pattern (17) signifying initialization of the memory, including creation of an appropriate directory (16). Absence of the predetermined bit pattern signifies no initialization. The using units independently and asynchronously access the token area to verify initialization. The first using unit detecting no initialization. The first using unit detecting no initialization creates a directory in the memory for normal operation but, when a using unit, itself, is being powered up, a poll bit is set in order that initialization of the memory (10) can be delayed.
Inventors
- 👤 John Edward Kulakowski
- 👤 Raymond Lonnie Parsons
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 07:04
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0223; G06F12/0284
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
135 words
Data processing apparatus including multiple processing units, ( 11 ) each having private storage (13) and sharing common volatile storage (10) as a serially resuable resource, each processor being constrained to gain access to the common volatile storage via a stored value access control mechanism, characterized in that the access control mechanism causes a) the retention in or for each running processor externally of the volatile storage of the identity of a common location in the volatile storage and of a common multibyte value (17); and b) the comparison of the contents of the common location against the common multibyte value, equality granting access, and inequality forcing the testing processor to construct a directory (16) in the volatile storage and thereafter to load the common multibyte value into the common location in the volatile storage.
Claim 2
Dependent Claim
135 words
Data processing apparatus including multiple processing units, ( 11 ) each having private storage (13) and sharing common volatile storage (10) as a serially resuable resource, each processor being constrained to gain access to the common volatile storage via a stored value access control mechanism, characterized in that the access control mechanism causes a) the retention in or for each running processor externally of the volatile storage of the identity of a common location in the volatile storage and of a common multibyte value (17); and b) the comparison of the contents of the common location against the common multibyte value, equality granting access, and inequality forcing the testing processor to construct a directory (16) in the volatile storage and thereafter to load the common multibyte value into the common location in the volatile storage.
Claim 3
Dependent Claim
49 words
Apparatus as claimed in claim 1 wherein the common multibyte value is retained on a pin board (72), the contents of the location being read into an external register 69, a comparator (73) comparing the contents of the register and pin board and signally, appropriately, equality or non equality.
Claim 4
Dependent Claim
54 words
Apparatus as claimed in either preceding claim wherein each processing unit has a power-up control, part of the function of which is to cause the processing unit to attempt to access the common location and, if inequality is signalled, to set a poll bit to force a further access attempt at a later time.
Claim 5
Dependent Claim
36 words
Apparatus as claimed in any preceding claim wherein the said processing units are subsystem controllers (83) in a greater system incorporating host processors (80) whereby the access control mechanism overhead is not a host processor overhead.
Claim 6
Dependent Claim
27 words
Apparatus as claimed in claim 4 wherein the subsystem associated with the said processing units is a storage subsystem of which the volatile storage is the directory.
References Cited (Backward Citations)
No citation records indexed.
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