PC Fixed Disk Usage During Emulation
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
The IBM PC (Personal Computer) hardware interrupt level five is shared between the session for emulation of the IBM 5250 and the PC session. This allows concurrent usage of the fixed disk for application programs while 5250 emulation is running. The 5250 emulation program does not use any interrupt vectors other than those normally used by DOS and BIOS in the PC. This offers increased compatibility with other PC programs by virtue of using the existing interrupt vectors. The use of the fixed disk in the PC is interleaved with the 5250 emulation feature in a transparent fashion. The Enhanced PC/5250 Emulation Adapter can generate a hardware interrupt request. The request must enter the PC's 8259 interrupt controller chip. The IBM PC has reserved all eight 8259 interrupts for other purposes.