Units are needed to comply with a protocol so which the interrupt-request (IRQ) traces may be shared. The PCI bus incorporates four interrupt lines, INTA# through INTD#, all of which can be found to every machine. Approximately 8 PCI gadgets share the same IRQ line (INTINA# via INTINH#) in APIC-enabled https://nathanlabsadvisory.com/cyber-security-policy-review/