Re: KA655 Kernel Compile and Corrupt Object Files

Hmm...

On 2025-05-24 14:38, Mouse wrote:
>>>>>> Josh wrote: TL;DR: gcc produces corrupted kernel object files on
>>>>>> a diskless, hardware KA$
>>>>> Mouse wrote: Do you have any particular reason to believe the
>>>>> hardware is not broken?
>>>> Josh wrote: Good question... [...]
>> Honestly, while possible, I seriously doubt there is a problem with
>> the CPU module.  If something was wrong there, I would expect way
>> more things to be noticed than just some object files being corrupted
>> while writing.
> 
> In general, so would I.  But I look at my VAX emulator and I notice how
> many instructions are unimplemented because I've never seen them used,
> and it seems plausible to me that there are a few instructions that are
> used only rarely, possibly only within the compiler (at least for the
> use cases tried so far).

It seems unlikely that it would be some instruction issue if the 
compilations fail on different files on repeated tries. In general, I 
would think it's very unlikely that some instruction would only occur 
when compiling a few files as well.

> Also relevant is that the brokenness appears nondeterminstic.  While it
> could be a mandelbug in the toolchain, I would expect something this
> blatant to be consistent if it's software.

I must admit that I must have missed it being non-deterministic. I 
thought it was the same files every time. If it is deterministic, I 
would point at the toolchain. If it in fact is non-deterministic, then 
hardware seems more likely.

> And, when a simulated VAX doesn't exhibit the symptom?  That
> substantially increase the plausibility of hardware issues, to me.

Again - if it is deterministic, I would suspect the toolchain. If not, 
then I'd also suspect hardware.

> Not necessarily CPU issues.  It could be, for example, flaky RAM.  But
> my preferred suspect is hardware trouble of some sort.

I think I'd like to get some clarification on if this actually is 
non-deterministic.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: [email protected]             ||  Reading murder books
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