[Simh] Way out idea for simh

[Johnny Billquist]

On 2016-04-21 10:01, Veit, Holger wrote:
>
>
> Am 20.04.2016 um 22:35 schrieb Sampsa Laine:
>>> On 20 Apr 2016, at 23:25, Phil Budne <phil at ultimate.com> wrote:
>>>
>>> Ken.Cornetet wrote:
>>>> I guess I need to shout this:
>>>> ******* KERMIT DOES NOT WORK ON SIMH EMULATED RTE-6/VM ********
>>> Why not?
>>>
>>>> Kermit does not exist (and probably couldn't feasibly exist) on any
>>>> earlier versions of RTE.
>>> Again, why not?
>>>
>>> Having just written a new shell for PDP-7 UNIX (because the original
>>> could not be found), I can't imagine much other than a lack of
>>> something resembling a serial console that would prevent _some_
>>> version/subset of KERMIT (or something similar like X or ZMODEM) from
>>> being cobbled together.
>>>
>> And since the connection can be assumed to be lossless, the protocol
>> could be really simple, e.g. something like this:
>>
>> G=Guest, H=Host
>>
>> Example of a write operation..
>>
>> G:    WRITE-FILE
>> H:    ACK
>> // Now we send the file structure / word size etc
>> G:    FILE-META-DATA
>> G:    <file size and a bunch of OS specific stuff that is written to a
>> second file>
>> H:    ACK
>> G:    FILE-DATA
>> G:    <the actual data>
>> G:    ACK
>>
>> Done.
>>
> And this is just a non-formalized textual description of how FTP, or
> ZMODEM, or Kermit work. The fine print is in the "Now we send the file
> structure / word size etc".

I wouldn't go that far. FTP does not really work that way, unless you 
have a very loose definition of TCP and FTP. And I don't know much about 
XMODEM, but yes, this is a pretty close description of how KERMIT works.

	Johnny