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Patent Agency Ranking
公开(公告)号：BR8906142A
公开(公告)日：1990-07-31
申请号：BR8906142
申请日：1989-12-04
Applicant: IBM
Inventor： CHANG ALBERT , ROGERS MARK DOUGLAS
IPC: G06F3/06 , G06F12/08 , G06F12/10 , G06F12/1009
Abstract: Multiple external page table (XPT) structure geometries provide efficient organisation and management of paged, segmented virtual memory systems. First and second small XPT geometries are provided for file mapping of files of a predetermined size for code segments, and file mapping of files exceeding the predetermined size for process private segments, respectively. A large XPT geometry is for working storage segments containing shared library routines. A uniform addressing scheme accesses page state information for second small and large XPT geometries having root blocks. Selected XPT structure direct blocks are pre-allocated for large XPT structures for address ranges to be referenced to reduce page faults.
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公开(公告)号：DE3750337T2
公开(公告)日：1995-03-09
申请号：DE3750337
申请日：1987-01-08
Applicant: IBM
Inventor： ROGERS MARK DOUGLAS , O'QUINN II JOHN THOMAS , O'QUINN II JOHN CLAUDE
IPC: G06F12/10
Abstract: In a virtual memory data processing system, the use of a pageable External Page Table data structure for recording current status and disk address information for each virtual page in the system and a non-pageable or pinned table of tables, provides improved system performance when a large number of virtual pages are to be operated on in the same manner. As disclosed, each page of External Page Table entries can record a predetermined number of entries (512), depending on the byte capacity of each virtual page (2,048) and the size of each entry (4 bytes). One page of 512 entries corresponds to 1 megabyte of virtual storage (512 x 2,048) and also appears as one entry in a pinned External Page Table. The pinned External Page Table is referred to as the "XPT of the XPT," and has the same format as the pageable XPT. A 256 megabyte segment of virtual memory is representable in the XPT of the XPT by 256, 4 byte entries, or one-half of a page. … Where all virtual pages represented by a page of XPT entries are to be processed in the same way (i.e., created, destroyed), one operation on one entry in the XPT of the XPT is made, rather than 512 operations on the 512 entries of the XPT.
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公开(公告)号：DE3750824D1
公开(公告)日：1995-01-19
申请号：DE3750824
申请日：1987-01-08
Applicant: IBM
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公开(公告)号：DE3750824T2
公开(公告)日：1995-05-24
申请号：DE3750824
申请日：1987-01-08
Applicant: IBM
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公开(公告)号：DE3750337D1
公开(公告)日：1994-09-15
申请号：DE3750337
申请日：1987-01-08
Applicant: IBM
Inventor： ROGERS MARK DOUGLAS , O'QUINN II JOHN THOMAS , O'QUINN II JOHN CLAUDE
IPC: G06F12/10
Abstract: In a virtual memory data processing system, the use of a pageable External Page Table data structure for recording current status and disk address information for each virtual page in the system and a non-pageable or pinned table of tables, provides improved system performance when a large number of virtual pages are to be operated on in the same manner. As disclosed, each page of External Page Table entries can record a predetermined number of entries (512), depending on the byte capacity of each virtual page (2,048) and the size of each entry (4 bytes). One page of 512 entries corresponds to 1 megabyte of virtual storage (512 x 2,048) and also appears as one entry in a pinned External Page Table. The pinned External Page Table is referred to as the "XPT of the XPT," and has the same format as the pageable XPT. A 256 megabyte segment of virtual memory is representable in the XPT of the XPT by 256, 4 byte entries, or one-half of a page. … Where all virtual pages represented by a page of XPT entries are to be processed in the same way (i.e., created, destroyed), one operation on one entry in the XPT of the XPT is made, rather than 512 operations on the 512 entries of the XPT.
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