Systems, methods, and computer program products to improve performance of ported applications, such as a database, operating on UNIX system services for the OS/390

A computer-implemented method for aggregating asynchronous direct I/O access commands, said computer having a computer program application that does application I/O caching and includes ordered computer code, said each ordered computer code having at least one said asynchronous direct I/O access command that operates with said application I/O caching, said computer supporting I/O request chaining, said computer having a file system that locates storage space for said computer code on said disk, said computer that executes said computer program application, the method comprising:

• locating said at least one asynchronous direct I/O access command;
• associating said at least one asynchronous direct I/O access command with at least one OS/390 UNIX HFS file;
• associating said at least one OS/390 UNIX HFS file with at least one VSAM file;
• chaining said asynchronous direct I/O access command into at least one aggregated I/O access command in said computer program application;
• associating said at least one aggregated I/O access command with said at least one VSAM file;
• identifying a terminus point that is ordered in said ordered computer code;
• issuing said at least one aggregated I/O command until said terminus point is reached;
• and
• when said terminus point is reached and if said at least one aggregated I/O command remains, issuing a final said at least one aggregated I/O access command.

A computer system for bypassing I/O operations of a file system included in said computer system, said computer system having a computer program application that includes ordered computer code, said ordered code including I/O access commands, said file system that is optimized for queued said I/O access commands, comprising:

• said file system as an OS/390 UNIX Hierarchical File System;
• asynchronous direct said I/O access commands that are included in said application ordered computer code;
• and
• said file system that is bypassed by executing said asynchronous direct I/O access commands by use of a different file system.

A computer system for aggregating asynchronous direct I/O access commands, said computer having a computer program application that does application I/O caching and includes ordered computer code, said each ordered computer code having at least one said asynchronous direct I/O access command that operates with said application I/O caching, said computer supporting I/O request chaining, said computer having a file system that locates storage space for said computer code on said disk, said computer that executes said computer program application, comprising:

• said at least one asynchronous direct I/O access command;
• said at least one asynchronous direct I/O access command that is associated with at least one OS/390 UNIX HFS file;
• said at least one OS/390 UNIX HFS file that is associated with at least one VSAM file;
• said asynchronous direct I/O access command that is chained into at least one aggregated I/O access command in said computer program application;
• said at least one aggregated I/O access command that is associated with said at least one VSAM file;
• a terminus point that is ordered in said ordered computer code;
• said at least one aggregated I/O command that is issued until said terminus point is reached;
• and
• when said terminus point is reached and if said at least one aggregated I/O command remains, a final said at least one aggregated I/O access command that is issued.

An article of manufacture comprising a program storage medium readable by a computer and embodying one or more instructions executable by said computer for bypassing I/O operations of a file system included in said computer, said computer having a computer program application that includes ordered computer code, said ordered code including I/O access commands, said file system that is optimized for queued said I/O access commands, wherein:

• computer-readable program code identifies said file system as an OS/390 UNIX Hierarchical File System;
• computer-readable program code locates asynchronous direct said I/O access commands that are included in said application ordered computer code;
• and
• computer-readable program code bypasses said file system by executing said asynchronous direct I/O access commands by use of a different file system.

An article of manufacture comprising a program storage medium readable by a computer and embodying one or more instructions executable by said computer for aggregating asynchronous direct I/O access commands, said computer having a computer program application that does application I/O caching and includes ordered computer code, said each ordered computer code having at least one said asynchronous direct I/O access command that operates with said application I/O caching, said computer supporting I/O request chaining, said computer having a file system that locates storage space for said computer code on said disk, said computer that executes said computer program application, wherein:

• computer-readable program code locates said at least one asynchronous direct I/O access command;
• computer-readable program code associates said at least one asynchronous direct I/O access command with at least one OS/390 UNIX HFS file;
• computer-readable program code associates said at least one OS/390 UNIX HFS file with at least one VSAM file;
• computer-readable program code chains said asynchronous direct I/O access command into at least one aggregated I/O access command in said computer program application;
• computer-readable program code associates said at least one aggregated I/O access command with said at least one VSAM file;
• computer-readable program code identifies a terminus point that is ordered in said ordered computer code;
• computer-readable program code issues said at least one aggregated I/O command until said terminus point is reached;
• and
• when said terminus point is reached and if said at least one aggregated I/O command remains, computer-readable program code issues a final said at least one aggregated I/O access command.