[Simh] MOP header specs?

[Johnny Billquist]

On 2018-02-25 02:41, Paul Koning wrote:
> 
> 
>> On Feb 24, 2018, at 8:27 PM, Johnny Billquist <bqt at softjar.se> wrote:
>>
>> On 2018-02-24 17:21, Paul Koning wrote:
>>>> On Feb 23, 2018, at 8:52 PM, Johnny Billquist <bqt at softjar.se> wrote:
>>>> ...
>>>> Yes. But what difference does that make on the server side? The fact that the requested image is small enough to fit into one frame is just a detail that makes the client implementation easier.
>>> The difference is that the server is required to answer a request for secondary loaded with a single response packet holding the entire response.  For other loads, it can deliver the data in pieces, and the size of those pieces it its choice.  For the second loader, it does not have that choice.
>>
>> The MOP servers I know of don't even know about that distinction. They just serve the image. If it fits in one frame, it will come in one frame. If it don't, it won't. The server can't do more than that.
> 
> If so, then that's fine.  I'm just pointing out that the protocol spec has an explicit requirement for the secondary load request to be answered with a complete load response (data with transfer address) in a single message.

I need to correct myself. There is a difference on the server side 
depending on what was requested (I clearly haven't read this code in too 
long a time).
Looking at the RSX MOP server:
A secondary or tertiary boot image is sent using "MEMORY LOAD WITH 
TRANSFER ADDRESS". In the case of a tertiary bootstrap, that is the last 
message, while the others are just "MEMORY LOAD".
For a system image, the contents are sent with "MEMORY LOAD", but then 
afterwards there is instead a "PARAMETER LOAD WITH TRANSFER ADDRESS", so 
there is a distinction between boot loaders and general system images 
that the MOP server needs to know.
The RSX MOP server makes no distinction on the files used to serve the 
different types of requests. They are all processed the same way, and 
needs to have the same format. But obviously, a secondary bootstrap file 
must be small enough to fit into one message, or else it won't work.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol