Glossary
Glossary–2 VX4101A MultiPaq Instrument User Manual
Client
In shared memory protocol (SMP), that half of an SMP channel that does not
control the shared memory buffers.
CLK10
A 10 MHz, ±100 ppm, individually buffered (to each module slot),
differential ECL system clock that is sourced from Slot 0 and distributed to
Slots 1–12 on P2. It is distributed to each module slot as a single source,
single destination signal with a matched delay of under 8 ns.
CLK100
A 100 MHz, ±100 ppm, individually buffered (to each module slot),
differential ECL system clock that is sourced from Slot 0 and distributed to
Slots 1–12 on P3. It is distributed to each module slot in synchronous with
CLK10 as a single source, single destination signal with a maximum system
timing skew of 2 ns, and a maximum total delay of 8 ns.
Commander
In the VXIbus interface, a device that controls another device (a servant). A
commander may be a servant of another commander.
Command
A directive to a device. There are three types of commands:
In Word Serial Protocol, a 16-bit imperative to a servant from its com-
mander.
In Shared Memory Protocol, a 16-bit imperative from a client to a server, or
vice versa.
In a Message, an ASCII-coded, multi-byte directive to any receiving device.
Communication Registers
In word serial protocol, a set of device registers that are accessible to the
commander of the device. Such registers are used for inter-device commu-
nications, and are required on all VXIbus message-based devices.
Configuration Registers
A set of registers that allow the system to identify a (module) device type,
model, manufacturer, address space, and memory requirements. In order to
support automatic system and memory configuration, the VXIbus standard
specifies that all VXIbus devices have a set of such registers, all accessible
from P1 on the VMEbus.
C-Size Card
A VXIbus instrument module that is 340.0 mm × 233.4 mm × 30.48 mm
(13.4 in. × 9.2 in × 1.2 in).