Re: AlphaStation 200 F4 error

In article
<8c6029fb-e87a-48c3-ba26-71042bc20077@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Rich Jordan <jordan@xxxxxxxxxxx> wrote:

On May 27, 11:10 am, VAXman- @SendSpamHere.ORG wrote:
I'm trying to boot an old AlphaStation. The console initialization
countdown stops at F4. The LEDs on the rear apron of the AS200 also
mirror this code [**** o*oo] F4. I've googled and haven't found any
definitive answer on this code. One document said "reserved to DEC"
which is not very informative.

Any pointers, help, etc. greatly appreciated.

--
VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)COM

"Well my son, life is like a beanstalk, isn't it?"

http://tmesis.com/drat.html

The service doc I have shows the same; 'reserved for future use' but I
did find the following snippet: "When power is applied to the system,
the diagnostic LEDs start decrementing as tests complete successfully
If a test fails, the display does not change. Therefore, when a
failure occurs , the LED code is pointing to the test which last
passed."

That means its test F3 that failed; the service guide says "Load the
DROM code into memory.". F2 apparently continues that, and F1 should
be "Successful load and checksum of DROM".

The popup says that in the event the DROM load fails, SROM will
attempt to load the selected firmware (ARC or SRM), and failing that
will drop into a "mini console" that is apparently available to
manufacturing. Is that the serial port on the MLB in the back? The
docs do not say.

The mini-console is a feature built into the SROM firmware of most
(all?) alpha systems. Sometimes the mini-console is only available if
you move a jumper to a different position to load alternate SROM code.

On power-up or reset, Alpha CPUs load the SROM (Serial ROM) code, 1 bit
at a time, using 2 dedicated pins (clock + data) on the CPU chip. The
code loads directly into the CPU's instruction cache. The the CPU
starts executing instructions from the cache.

This code normally finds the SRM firmware in ROM, decompresses it,
copies it to RAM, and transfers control. If something goes wrong,
NOTHING is available except those 8 KB of instructions in the cache. No
memory, no I/O devices, no SRM firmware -- nothing.

The alpha designers added a debug tool for this contingency -- the SROM
mini-console. The two pins that load the SROM code at power-up are
reused to make a 2-pin serial interface directly into the CPU. The pins
are usually connected to a header somewhere on the motherboard or CPU
board. They aren't routed to a real connector on the back of the
machine. The voltage is nonstandard, but if you have the right
connector and circuit, you can connect a terminal. The serial port runs
at 9600 baud, with timing via delay loops in the code. You end up with
a little command-line debugger, dumber than XDELTA, that lets you
examine and deposit memory. With that, you can load any diagnostics you
need into main memory and transfer control to something smarter.

Some versions of the mini-console were documented in the manuals that
came with the old-time Alpha developer boards.


There's also this note: "Check J3: If "normal", then HW_REI to PAL.
If J3 is set to S-Port, go to the SROM mini-console."

That does happen after the test that failed but perhaps the J3 jumper
setting may be worth checking to see if you can get access to further
diagnostics.

I wonder if you have had a firmware corruption. Perhaps even to the
point that you need to use a failsafe boot...
.

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