DIO-I: 16-bit wide, 16Mb (24-bit) address space bus which supports the bulk of HP's controllers: HP-IB adaptor, SCSI host adaptor, serial interfaces and some older graphics interfaces.
DIO-II: 32-bit wide, 4Gb (32-bit) address space bus which mostly supports graphics interfaces and the Human Interface Board (HIB, aka "IO card") which consists of LAN, fast HP-IB (or SCSI), DMA, RS232, HIL, and internal HP-IB.
HP-IB: HP's implementation of IEEE 488.1. Supports a variety of HP peripherals including disks, tapes, printers and plotters. Each HP-IB can have up to 8 slaves. Comes in two flavors:
1. Slow or standard speed (aka the "internal" HPIB): 300KB/sec (DMA) and 50KB/sec (non-DMA) max. For low-bandwidth peripherals like instrument controllers and printers/plotters. There is one of these (the internal HP-IB) on every model machine I know of plus there is a DIO-I card version.
2. Fast or high speed:
1.2MB/sec (DMA) and 50KB/sec (non-DMA) max. For high speed devices like disks and tapes. Comes as either a DIO-II "daughter" board or a DIO-I plug-in card. A single system can have one "internal", one daughter board and any number of DIO-I style HP-IB interfaces. SCSI: Single-ended sync/async SCSI-I (I think) implementation. Each SCSI bus can have up to 8 "slaves", 1 of which (slave 7) is the controller (host-adaptor) itself. Again, there are two variations:
1. DIO-II "daughter" board:
1.5MB/sec (async) and 4.0MB/sec (sync) max. Max of one such interface per machine since it is a bolt-on board that connects directly to the HIB.
2. DIO-I plug-in card:
1.5MB/sec (async) and 2.67MB/sec (sync) max. Can have more than one of these depending on how many DIO slots there are.
VME: VME C.1 implementation.
Don't know much about this, even though we have a couple. Haven't done any support for the interface, not even sure it needs any. I think Van can tell you more about the limitations of this. There is an expander box version with 4 VME C.1 slots or there is a DIO card plus VME C.1 interface card for connecting to an external card-cage. HP only has one VME card product, an SNA interface.
HIL: Human Interface Link. This is the "bus" that the graphical input devices (e.g. keyboard, mouse, knobs, tablet, buttons) sit on. One HIL "loop" can hold up to 7 devices. We only support one HIL.