Method of Monitoring Open Files for Any Application on a Personal Computer
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
The Application Selector program monitors DOS function calls to determine when files are opened and closed on each diskette, and maintains this information in an 'Open File Table' which is shown above. This table is used to determine when to verify that the diskette containing the open file is still in the same drive. The diskette must be in the correct drive to prevent diskette or data loss. A DOS Function Call is a software interrupt (21H), which gives control to the DOS function call processor. Information passed in registers tells DOS what function it is to perform, and other information pertinent to the requested operation. The processor architecture directs processing on an interrupt to the address contained in a specific memory location (interrupt vector), for each interrupt.