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METHOD for LOCATING a DATA STRUCTURE in a PROCESSOR

IP.com Disclosure Number: IPCOM000040773D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 4 page(s) / 39K

Publishing Venue

IBM

Related People

Graham, CS: AUTHOR [+3]

Abstract

The method utilizes common control structures and delayed binding and functions by: (a) requesting a particular structure; (b) detecting that the structure is not present; (Image Omitted) (c) adding an identifier for the structure to a list of unlocated structures; (d) subsequently, loading a new data structure into the processor; (e) determining whether the new data structure is the requested structure; (f) if so, indicating that the requested structure has been found, and erasing its identifier from the list; (g) repeating steps (d-f) whenever a new structure is loaded. The method utilizes system control blocks which have a generally common structure.

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METHOD for LOCATING a DATA STRUCTURE in a PROCESSOR

The method utilizes common control structures and delayed binding and functions by: (a) requesting a particular structure;

(b) detecting that the structure is not present;

(Image Omitted)

(c) adding an identifier for the structure to a list of unlocated structures;

(d) subsequently, loading a new data structure into the

processor;

(e) determining whether the new data structure is the requested

structure;

(f) if so, indicating that the requested structure has been

found,

and erasing its identifier from the list;

(g) repeating steps (d-f) whenever a new structure is loaded.

The method utilizes system control blocks which have a generally common structure. This common structure includes a name, type, size, and other data unique to a particular item (see Fig. 1). These control blocks with common structure in turn allow many operating system functions to utilize some common code paths. For example, the addition of any new item can utilize a common name checking routine (see Fig. 2). Further, checking the status of an item of type-B (see Fig. 1) could utilize the same common routine to locate an item of a particular name. The common routine returns the results of its operation: for this example, it indicates if an object of a given name was found. The code invoking the function then determines what action to take. When an item is to be created, locating the name indicates that the new name would be a duplicate. When looking for an item, locating the name signifies that the desired item has been found. It is possible to repeatedly apply the use of common code paths at successively higher levels. For example, creation of any new item of any type starts with

(Image Omitted)

a common code path. Internally, this common create code utilizes the common check for an existing name and some other common routines. This localization of one function to one specific piece of code was key to an efficient implementation of the delayed binding function.

In general, it is possible to request from an operating system the address, or some system ID, of items known to the operating system. This method extends this capability to items which will be created in the future. When a binding request is received by the operating system, the common name checking routine is invoked to search for the item. When the item is found, then the desired information is

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returned to the requestor. In some cases, failure to find an item is indicative of some error condition. However, at times it is an advantage to request information about an item which may not now exist but will be created in the future. When this is the situation, an additional parameter on the request to the system indicates that this is a "delayed" binding request. When a binding request cannot be immediately satisified, and the delayed indicator is set, then the system records the name of the item desired and the location where the item's ID...