> On Feb 11, 2020, at 6:00 PM, Johnny Billquist <[email protected]> wrote:
>
> On 2020-02-11 23:25, Paul Koning wrote:
>>> On Feb 11, 2020, at 3:15 PM, Henk Gooijen <[email protected]> wrote:
>>> ...
>>> As you can see from the printed debug statements, in the function rk_go()
>>> the cylinder number goes higher than the maximum number of cylinders
>>> possible on an RK05. Then, the function rk_set_done() is called with the
>>> variable "error" holding RKER_NXC (64 decimal == 000100, octal == RKER_NXC)
>>> ==> turns on the FAULT indicator.
>>> SIMH does not generate an error, all is OK, as is on the real PDP-11 / RK05.
>>> For now, I "solved" this by adding "if (error != RKER_NXC)", but that
>>> will exclude all "non-existing cylinder" errors, not only the error that
>>> is generated at the end of the FORMAT RK0: command.
>>> Is this incorrect behavior in SIMH, simulating the RK05? I don't believe
>>> that, so is the RKER_NXC handled in the RK.SYS driver or in RT11 in case of
>>> the execution of the FORMAT command?
>> I only have some V2 sources. The zero directory operation, which I think is
>> what "format" uses, just grabs the device size and writes an empty
>> directory. So I'm puzzled by the reference to an invalid sector.
>
> I would expect the INIT to write the empty directory. I would expect FORMAT
> to actually format the disk pack, meaning writing the sector header for each
> sector on the whole packet.
> A little surprised, though, that the formatting wouldn't know how many tracks
> there are, and continue until it hits an error.
There is no such thing as "format", in the sense of writing sector headers, on
an RK05.
>> The driver calls that a hard error (no retrying).
>> But why would you turn on the FAULT light on your RK05 for that? Fault, on
>> the RK05, means servo failure, in particular it means the servo grid light
>> bulb has burned out. References to invalid disk addresses don't light FAULT
>> in an RK05. The Peripherals handbook describes it as (a) that light bulb
>> failed, or (b) write current is present without a write command, meaning
>> your disk probably has been wiped by an electronic failure.
>
> Sounds like simh does it wrong, then.
I don't think Henk was talking about SIMH having a problem, though I got a bit
confused. The question was about the fact that the fault light was coming on.
My answer is: don't implement that light, there is no condition in the emulated
drive that matches what that light does in the real drive.
paul
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