22 Apr
2021
22 Apr
'21
2:23 p.m.
On 4/22/21 6:16 AM, Johnny Billquist wrote:
The 86x0 do load all microcode from the FE at startup
time. It takes a
little while to boot an 86x0 because of this. The power system is also
software controlled, and at power up, only a single power supply is on.
Everything else is turned on by the FE at a later stage. Fun to watch
the system start up. Slowly, LED after LED lights up, as different parts
gets initialized.
This is the way IBM mainframes (post-S/390, and a few earlier than
that) work too. You've probably seen the ones with the laptops built
into the front of the CPU cabinet; they run OS/2 up to the z890, and
after that they run Linux. They inject the microcode into the hardware
as a part of the POR (Power-On Reset) process. Booting (er, IPLing)
them takes quite a while, depending on the configuration.
That's how IBM turns them into zero-resale-value bricks when at
decommissioning time.
I just love that machine. :-)
I wish there were more of them around. :-(
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA