Re: MCA PowerPC (250/41t) Documentation Scanned

While I'm not sure about writing in the format of the serial number to 
another ROM dump of the same machine (which is partially documented in 
the book I scanned), I don't see the hardware having any sort of special 
checks for serial numbers matching the original one (unlike modern 
ThinkPads, etc.). If anything writing a ROM with a different serial 
number would mostly matter for software licensing or if you had multiple 
machines on the same network. I see no reason you couldn't flash a ROM 
dump from another 220 on a 220 with a failed ROM just to get it working.

What I have known for a fact is that the one MCA machine I know of 
having a firmware update documented on IBM's FTP had only a readme file 
(for the 7015-R50), and a note saying to call support for the file 
despite being a flash rom machine. This makes me wonder if the image had 
to be serialized before they sent it out to the customer. Furthermore 
multiple MCA machines had new EPROM versions that had to be programmed 
with the CPU ID and Ethernet address according to the .boo files hosted 
on the Ardent Tool site.

Both the Hardware Technical Information - General Architectures (Chapter 
4) and General Information (Chapter 6) books on Bitsavers, and the book 
I scanned (Chapter 13, VPD among other places) talk about this format 
some and how it works. Essentially the IPL EPROM checks for a checksum, 
board part number, EC level, serial number, and the ROM 
copyright/timestamp/part number. If the data is not there or the 
checksum is bad it fails POST with code 211. Judging by the what's in 
the .boo documents, I'm sure these ROMs also include a MAC address.

As for the ROM, I've dumped the ROM of my 7006-41t (a very similar 
machine to the 250) if anyone wants to poke around. I'm almost certain 
that if you just take an EPROM dump of your machine and write out 
another ROM chip when the old one gives you checksum errors, it'll work. 
Easily visible in a text editor or hex editor as a string is the part 
number, copyright, and the VPD header showing some of the same things 
marked in the book. The video ROM for the GXT150L also has a VPD header 
with a similar structure.

https://archive.org/details/700641tfw

Jake

On 9/17/2021 3:44 PM, Chris Hanson wrote:
> Is the format of this serial number information known so new ROMs can be created from similar ROMs?
>
> E.g. if my POWERserver 220 loses an EPROM, (1) are there backups of the 220 ROM available and (2) can I tweak the bits in the ROM to still have an accurate serial number?
>
>    -- Chris
>
>> On Sep 17, 2021, at 7:55 AM, Jake the Snake <[email protected]> wrote:
>>
>> Oh definitely, your site's been a great resource for getting my RS/6000s working. One thing I'd mention too about the MCA machines is that if you get an MCA machine, you should dump or at the very least backup the EPROMs. The EPROM chips will eventually go bad and they also contain the machine serial number. I know for a fact at least a few RS6ks have died for this reason. These are usually on the CPU board or motherboard/planar.
>>
>> On a related note, the Ardent Tool of Capitalism database actually has MCA RS/6000 information as well including motherboard layouts with listings of each component (for most models).
>>
>> https://www.ardent-tool.com/RS6000/index.html
>> https://www.ardent-tool.com/RS6000/7006/7006-41x.html
>>
>> Jake
>>
>> On 9/16/2021 3:48 PM, Kevin Bowling wrote:
>>> http://ps-2.kev009.com/rs6000/rs6000-netbsd.html
>>>
>>> http://ps-2.kev009.com/rs6000/docs/POWERstation%20Hardware%20Technical%20Information%20-%20General%20Architectures%20-%20cleaned%20OCR.pdf
>>>
>>> Probably other interesting stuff in the dirs.
>>>
>>> Regards,
>>> Kevin
>>>
>>> On Wed, Sep 15, 2021 at 9:56 PM Jake the Snake <[email protected]> wrote:
>>>> Hello, so in my free time I like to scan forgotten programming books and
>>>> whatnot. Recently I picked up a copy of an IBM book titled "RISC
>>>> System/6000 PowerPC System Architecture" and scanned it in. At first I
>>>> thought it had to do with the PReP platform, but once I got ahold of it
>>>> I quickly realized it's for the late MCA machines. The book contains
>>>> information on the MCA models used in the RS/6000 port (namely the 250)
>>>> and advertises itself as important for anyone porting a different OS to
>>>> the RS/6000.
>>>>
>>>> I've uploaded the book scans to IA and I'm posting it here since I know
>>>> a while back there was interest in trying to scan RS/6000 MCA-era
>>>> documentation. I'm hoping this will be of interest to anyone interested
>>>> in that port.
>>>>
>>>> Here is the book:
>>>> https://archive.org/details/ibm-risc-system-6000-power-pc-architecture/
>>>>
>>>> Jake
>>>>