System for transferring resident programs to virtual area and recalling for instant excution in memory limited DOS system using program control tables

• US 5,212,633 A
• Filed: 08/18/1989
• Issued: 05/18/1993
• Est. Priority Date: 08/18/1989
• Status: Expired due to Fees

• Current Assignee: ShareData, Inc. (Morgan Stanley)
• Original Assignee: Sharedata
• Inventors: Franzmeier, James W.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Kim, Ken S.
• Application Number:
  US07/395,527
• Time in Patent Office: 1,369 Days
• Field of Search: 364/200 MS File, 364/900 MS File
• US Class Current: 703/23
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 9/445 Program loading or initiating bootstrapping G06F9/4401; security arrangements for program loading or initiating G06F21/57
• CPC Class Codes: G06F 9/463 Program control block organisation
• CPC Class Codes: G06F 9/54 Interprogram communication

Abstract

A DOS computer system which effectively extends the DOS main memory capacity without the addition of supplemental random access memory (RAM) to the DOS main memory. The system enables application programs to be transferred from secondary hard disk memory to RAM on an as needed basis and enable active application programs in RAM to be placed in suspension in virtual memory for instantaneous recall to RAM to become active application programs and be executed from the point at which the application program was suspended for transfer to virtual memory.

Claims

1. A computer system run under a disk operating system (DOS) and including

(a) main memory means including a limited storage area for storing at least one application program to become an active application program and be executed;

(b) secondary memory means including

(i) an area for storing resource data including resident files,

(ii) an area for storing inactive resident application programs for transfer to said limited storage area of the first memory means for execution, each of the resident programs sized to be stored within an area having the storage capacity of the limited storage area and each including a data storage (DS) area and a computer logic storage (CS) area,

(iii) a virtual memory area for storing, in suspension, an application program transferred from the limited storage area prior to completion of execution of the program;

(iv) a work area for, during execution of an active application program in the limited storage area, storing program data in excess of the storage capacity of the DS are of the active application program;

(c) controller means responsive to said active program for operating on the resource data;

(d) keyboard means for entering user commands for controlling execution of application programs and for controlling the transfer of application programs between the main memory means and the secondary memory means;

(e) application transfer means responsive to a resident application program request resulting from user commands or the execution of a presently active application program in the limited storage area to transfer a corresponding resident application program from secondary memory to the limited storage area of the primary memory means to become an active program and be executed;

(f) application program suspension means responsive to operation of an application program suspension request resulting from user commands or the execution of a presently active application program in the limited storage area to

(i) transfer the corresponding application program, including all data in the DS area of the corresponding program, from active status in the limited storage area to the virtual memory area in suspension prior to completion of execution in the main memory means of the corresponding application program,

(ii) determine the DS address entry, if any, identifying the location in scanning data in the DS area of the corresponding active application program when the program is suspended for transfer to the virtual memory area and to transmit the DS address entry,

(iii) determine the CS address entry, if any, identifying the location in executing logic steps in the CS area of the corresponding active program when the program is suspended for transfer to the virtual memory area and to transmit the CS address entry, and,

(iv) determine the work area address entry, if any, identifying the location in the work area of the secondary memory means of program data from the corresponding active application program which is stored in the work area when the corresponding active program is suspended, and to transmit the work area address entry;

(g) memory manager means responsive to operation of the

(i) application program transfer means for surveying the limited storage area and assigning an application program storage space in the limited storage area for storing the corresponding resident application program to be transferred into the main memory means, and,

(ii) application program suspension means for surveying the virtual memory area and assigning the application program storage space in the virtual memory area for storing the corresponding application program to be transferred from active status in the limited storage area in suspension into the virtual memory area;

(h) transmission means responsive to the operation of the

(i) application program transfer means for creating a LS program location address entry indicating the location of the corresponding application program in the limited storage area when the corresponding resident program is transferred from the secondary memory means into the limited storage area and for transmitting the LS program location address entry, and

(ii) application program suspension means for creating a VM program location address entry indicating the location of the corresponding application program in the virtual memory area when the corresponding program is transferred from active status the limited storage area in suspension into the virtual memory area and for transmitting the VM program location address entry;

(i) application program control table means responsive to operation of the application program transfer means

(i) for creating an application program control table corresponding to the resident application program to be transferred from the secondary storage means to the limited storage area to become active and be executed, each program control table containing information used in transferring the corresponding application to and from suspension in the virtual memory area and in controlling execution of the corresponding application program,

(ii) generating a corresponding program control table identification entry, each program control table identification entry linking the application program to the corresponding program control table,

(iii) for receiving and storage in the control table the transmitted

(1) LS and VM program location entries transmitted by the transmission means for the corresponding application program,

(2) DS entries transmitted by the program suspension means for the corresponding application active program when the corresponding application program is suspended,

(3) work area address entries transmitted by the program suspension means for identifying the location in the work area of program data from the corresponding active program stored in the work area when the corresponding program is suspended, and

(4) CS entries transmitted by the program suspension means for the corresponding application active program when the corresponding application program is suspended,

the most recent of the entries for each of (i)(iii)(1), (i)(iii)(2), (i)(iii)(3), and (i)(iii)(4) being identified in the control table;

(j) application program recall means responsive to operation of an application program recall request resulting from user commands or the execution of a presently active application program to transfer a corresponding suspended application program including the data in the DS area of the corresponding suspended application program from the virtual memory area to the limited storage area to be an active application program to be executed; and

,

(k) means responsive to operation of the application program recall means for examining in the control table for the corresponding recalled application program the most recent

(i) program location address entry to locate the corresponding recalled application program in the virtual memory area,

(ii) DS address to determine the address in the DS area of the corresponding recalled application program when the corresponding recalled application program was suspended, and

(iii) CS address to determine the address in the CS area of the corresponding recalled application program when the corresponding recalled application program was suspended.

2. The computer system of claim 1 including means for an active application program in the limited storage area to send a message to another application program, including

(a) message transfer means responsive to a message transmittal request resulting from user commands or the execution of a presently active application program to transmit a message from a corresponding active application program in the limited storage area, the message including data identifying the application program receiving the message;

(b) application program message control means responsive to operation of the message transfer means for

(i) creating an application program message table corresponding to the application program receiving the message transmitted by the message transfer means from the corresponding active application program, each message table containing information used in transmitting the message to the receiving application program, and

(ii) generating for the message table a corresponding receiving program message table identification entry, each program message table identification entry linking the receiving application program to the corresponding message table;

(iii) receiving the message transmitted by the message transfer means and storing the message in the message table corresponding to the application program receiving the message; and

,

(c) message transmittal means responsive to a message transmittal request resulting from user commands in the activated receiving application program or to the execution of the active receiving application program to transmit the message from the corresponding message table to the activated receiving application program.

3. The computer system of claim 1 including means for selecting a resident file for use in an active application program and for monitoring the location of the file in the main memory means and the secondary memory means, including

(a) file selection means responsive to a select file request resulting from user commands during a presently active application program or from the execution of a presently active application program to select a corresponding resident file from the secondary memory means for use in execution of the active application program;

(b) file handle table means responsive to operation of the file selection means for

(i) creating a file handle control table corresponding to the selected file, each file handle control table containing information used in transferring the active application program to and from suspension in the virtual memory area and in transferring the selected file between the secondary memory means and the main memory means,

(ii) generating for the file handle control table a corresponding file control table DOS handle, each DOS handle linking the selected file to the corresponding file control table,

(iii) when the active application program is transferred to the virtual memory area or when the selected application program to storage in secondary memory, releasing the DOS handle from the control table to subsequently be assigned to another file or resident application program being transferred from the secondary memory means to the main memory means,

(iv) generating for the file handle control table a corresponding file control table auxiliary handle, the auxiliary handle linking the selected file to the corresponding file control table and remaining in the file control table when the active application program in which the selected file is used is transferred to the virtual memory area or when the corresponding selected file is transferred from the active application program to storage in the secondary memory means, and

(v) creating for the file handle control table a file application program entry linking the selected file to the corresponding application program most recently utilizing the selected file.