STREAMS/UX for the HP 9000 Reference Manual

STREAMS/UX Multiprocessor Support

Running Modules and Drivers in Uniprocessor Emulation Mode

When a module is pushed onto a stream, STREAMS/UX checks if either the

module is conﬁgured for UP emulation or if the stream is running under UP

emulation. If either condition is true, the module and the entire stream run

under UP emulation. Also, when the module is popped, the stream does not

change back to its original mode.

When a driver is linked under a multiplexor, STREAMS/UX checks if both

streams run in the same mode. If they do not, STREAMS/UX changes the

MP scalable stream to run in UP emulation mode. When the driver is

unlinked, STREAMS/UX does not change a stream back to its original

mode.

STREAMS/UX does not support mixing MP scalable and UP emulation

modules in an upper mux because an upper mux is a clonable device.

STREAMS/UX does not detect that upper mux streams are related. In

particular, STREAMS/UX does not support pushing a UP emulation module

onto only one MP scalable upper mux stream. STREAMS/UX changes only

this one stream to run under UP emulation. It does not change the control

stream or the other upper mux streams. You should design your modules and

drivers so that only MP scalable modules are pushed onto MP scalable upper

muxes. Also, STREAMS/UX does not support linking a UP emulation

driver under an MP scalable upper mux. STREAMS/UX only changes the

control stream to run under UP emulation. It does not change the other

upper mux streams. You should link only MP scalable drivers under an MP

scalable upper mux.

Some examples of supported streams conﬁgurations which contain both MP

scalable and UP emulation modules and drivers are listed below.

• If an MP scalable driver is linked under a UP emulation mux, STREAMS/UX

changes the MP scalable driver to run in UP emulation mode. For example, DLPI

is MP scalable in 10.0. When it is linked under UP emulation SNA,

STREAMS/UX changes the drivers to run in UP emulation mode.

• When an MP scalable module is pushed onto a UP emulation stream,

STREAMS/UX runs the module under UP emulation. For example, timod is MP

scalable. When it is pushed onto a UP emulation OSI stream, it runs under UP

emulation.

• When a UP emulation module is pushed onto an MP scalable stream,

STREAMS/UX changes the entire stream to run under UP emulation. For

example, DLPI is MP scalable in Release 10.0. When UP emulation Portable

Netware modules are pushed onto DLPI, the entire stream runs in UP emulation