- The VAX 11/780 runs the VAX Diagnostic Supervisor the EVKAE (Privilege
Architecture Exercisor) tests cleanly.
All other Unibus VAXen execute different instructions in EVKAE
Test 8 (KERNEL STACK NOT VALID) subtest 2 when compared to the 11/780.
On these processors a REI instruction with reserved operands is invoked and
this causes a failure of this subtest for these processors.
We avoid this diagnostic test that fails.
- The VAX 8200 has some issues with the VAX Diagnostic Supervisor.
Specifically, the EVKAA (Hardware Core Instruction) test uses the processor
interval timer to measure the passage of time and expects the interrupts
that are generated to occur at IPL 24 (0x18). Meanwhile, the actual
hardware is documented to generate Interval Timer interrupts at
IPL 22 (0x16). EVKAA fails when interrupts occur at IPL 22(0x16).
If the processor is is built with Interval Timer interrupts at IPL 24(0x18),
then EVKAA passes, but the EVKAE (Privileged Architecture Exercisor)
Interval Timer test fails since the interval timer interrupts occur at
IPL 24(0x18) and not at IPL 22(0x16).
Once operating systems are running, operating system behavior will
generally be unaffected if Interval Timer interrupts occur at a higher
IPL than the OS expects, so the VAX 8200 is built that way and we avoid
the diagnostic that fails.
- The DEC supplied instruction diagnostics actually time the execution of
instructions being tested using the interval timer and the time of day
clock. When instructions take too long, they fail the test. The
VAX 11/730 simulator actually fails some of these instruction tests when
run at precisely .3 the instruction rate of the VAX/11 780. We therefore
adjust the nocalibrate execution rate to 320K vs the VAX 11/780 running
at 1000K.
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