HP 9000 Series 310 Service Information Manual page 95

7. Determine if Internal HP-IB is Present:
Register A6 is set to the address of the next step. Channel zero of the DMA card is
disarmed if the DMA card is present. An internal HP-IB card is present if register three
is set up such that bit 7
=
1, bit 6
=
0 and bit 0
=
0, and if bits 7 and 6 are unaffected
by writing, and if bits 7, 6, and 0 are unaffected by bus precharging.
8. Determine Which, if any, Alpha video card is Present:
Register A6 is set to the location of the top RAM test routine. Note that only video
assemblies with a CRT ID registers are supported.
9. Initialize and Blank Alpha Display Controller, if Present:
If an HP 98546A card set is present, then it will be initialized and blanked.
10. Top RAM Test:
Register A6 is set to the location of the fatal error handler routine. A memory test is
executed on just enough RAM to allow the rest of the Boot ROM code to operate. (A
"fatal error" will occur when there is not enough RAM.) If there is a memory failure, 8416
will be displayed on LEDs. If nlemory is missing, 4416 will be displayed on LEDs. If an
alpha display controller is present, the Boot ROM will also write one of these messages:
RAM FAILED ABOVE FFCOOO
RAM GONE ABOVE FFCOOO
for menlory failure and mernory missing, respectively. These messages will not be displayed
on a monitor through a bit-mapped video board.
NOTE
If high RAM fails or is missing, then the LEDs and beeper will give the
only notification on a system with a bit-mapped video board or remote
console.
11. Set Up Data Structures:
a. The two global variables SYSFLAG and SYSFLAG2 are set up.
b. ATTENDED is set to false. ATTENDED is a Boot supervisor flag which indicates
whether or not the keyboard has been accessed.
c. The test list is set up in temporary RAM.
d. The Boot list and device driver list are set up.
NOTE
The remaining steps depend upon a working RAM stack. As in the
previous steps, the LEDs are set to a new value before each step.
Boot Rom Functions
85