Booting an IBM MP 3000 S/390 System

[JP Hindin]

On Thu, 6 Aug 2015, Dave G4UGM wrote:
>> Booting an old CDC 6000-series machine meant mounting a "deadstart"
>> tape, pushing the button just below the screens on the DD60, entering or
>> editing the equipment status table, then going out for a smoke (not me) or a
>> cup of coffee, while the system copied the deadstart tape to disk.
>>   The next prompt was to enter the date and time.
>>
>> People are too impatient today.
>>
>> --Chuck
>
> Actually I remember booting an IBM4381 from cold after we shut it down over Christmas. Just pressing the Power button powered it up eventually, but I am pretty sure it took nearly an hour to get to the IPL prompt. So it did disk drives, then tape drives, then other bits and bobs. But when it spun up the disks it brought them up one at a time so the startup surges didn't trip the main breaker. The same with the tape drives. Then  it loaded the microcode into all the controllers. Then it booted the OS. As we were running VM this last bit took a few seconds (I think). I do know if VM crashed you screen logo frequently re-appeared before you had time to think.

Spinning off on this tangent, when I was learning how to fire up my Sun 
E10k I didn't realise it took so ruddy long for the SSP and the E10k to 
speak to each other.
So I was constantly asking the SSP for the E10k's power status (to see if 
they were communicating) and being told the SSP "wasn't the master".

I'd powered things up repeatedly and made all sorts of changes to the SSP 
config and just couldn't figure out what wasn't working. So one day I'm 
messing with it again and I'd walked over to the other side of the shop 
for a manual and gotten distracted and maybe ten minuted passed and all of 
a sudden all of the blowers dropped RPM and evened out. The SSP and E10k 
had finally finished their secret masonic handshake and the SSP did the 
equivalent of "Hey, dude, it's not 7000 degrees in here, you can chillax 
now".

"People are too impatient today" -- Chuck G

True enough. I just didn't know enough to know I should be patient.

  - JP