[Simh] VAXELN, rtVAX-1000, WTC, time

[Wilm Boerhout]

Mark Pizzolato schreef op 15-12-2018 om 21:42:
> On Saturday, December 15, 2018 at 12:09 PM, Wilm Boerhout wrote:
>
> [...]
>>
>> DBG(1041144)> CLK REG: todr_rd(ROM) - TODR=0xC3AA5B84
> This line ^^^ and all above it are done by the MicroVAX 3900 boot
> ROM and have nothing to do with ELN.
>
>> DBG(7056415)> CLK REG: todr_rd() - TODR=0x132A4
>> DBG(7056419)> same as above (1 time)
>> DBG(9598293)> CLK REG: todr_rd() - TODR=0x133F0
>> DBG(11998428)> CLK REG: todr_rd() - TODR=0x13526
>> DBG(14398563)> CLK REG: todr_rd() - TODR=0x1365C
>>
>> Simulation stopped, PC: 800066EE (BEQL 800066EA)
>> sim> quit
>> Goodbye
>> NVR: writing buffer to file
>> CLK: writing buffer to file
>> Eth: closed tap0
> The few actual reads of the TODR during ELN's execution are returning low values (since nothing actually set the clock yet).
>
> Do you get the same result if you don't attach the CLK device?
>
> If the result is the same, then it would seem that ELN doesn't care to use the hardware clock for much of anything.  Maybe there is some setting within ELN that could influence more direct use of the clock.
>
> - Mark
>
Thanks Mark for clatifying this.

That might well be the case. That is why I'm interested how a real rtVAX 
preserves its clock. Maybe it didn't, and you had to enter the right 
time on every boot. In which case simh would be right. These systems 
would sometimes run for years. Documentation is scarce, however. I 
havesome leads th real rtVAX-systems, but not very soon.

Anyway, with MV3900 the behaviour doesn't change when I do not attach 
the CLK device. System time starts at VMS Zero.

Let's let it rest. I will go out on this thing called The Internet and 
look better for docs.


*Wilm*

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