[ih] NCP and TCP implementations

[the keyboard of geoff goodfellow]

let's not forget/what about the MTIP's?  i.e. the Terminal Interface
Processors with a Magnetic Tape unit attached...

recalling there was one at GWC and also perhaps another one at Norsar --
further recalling that they were used to "ship" data (from a magtape) to a
"host" somewhere else on the ARPANET.

how dose yours truly "remember" this?  cuz in the Tenex host table
<SYSTEM>HOST-NAME/DESCRIPTOR-FILE.TXT
there were several host "classification" types to "describe" what a given
hosts capabilities entailed: USER, SERVER, TIP, MTIP so that when you went
into a program such as telnet, it would "politely ignore" the USER
defined/declared host names and only recognize the SERVER hosts names... as
USER hosts only did/supported outgoing connections to SERVER hosts. :D

geoff

On Tue, Mar 10, 2020 at 8:07 AM Steve Crocker via Internet-history <
internet-history at elists.isoc.org> wrote:

> To create the TIP, a second bank of memory was added to the 316 and some
> interrupts and modes were added to enable switching back and forth between
> banks.  It was a bit of a kludge with some unexpected interactions.  The
> BBN crew finally sorted out the details and wrote a delightful titled "It's
> Amazing That it Works at all."
>
> On Tue, Mar 10, 2020 at 1:55 PM Bernie Cosell via Internet-history <
> internet-history at elists.isoc.org> wrote:
>
> > On 10 Mar 2020 at 13:23, Steve Crocker via Internet-hi wrote:
> >
> > > The TAC was an extension of the IMP.  The original IMP was built on
> > > the
> > > Honeywell 516 (and later 316) platform, which was a 16 bit twos
> > > complement
> > > computer.  I assume Hinden's reference to 15-bit arithmetic reflected
> > > the
> > > fact that the arithmetic was signed.
> >
> > I honestly cannot remember what the TAC was!!   Was that the TIP?
> >  Regardless,
> > yes, the x16s had 16-bit signed arithmetic with 10 bit addressing 9 bits
> > of page
> > address, 1 bit of "this page" or the 0 page, 16Kwords of memory.
> >
> > Things got more complicated with the 316 -- it supported 32K words.  What
> > we
> > did for the TIP [and maybe the TAC, whatever that was] was to keep the
> IMP
> > *unchanged* in the bottom 16K, and then in the upper 16K we wrote a
> > self-contained "host". There was some [small!] hack to fake interrupts
> and
> > input/output to this host but to the IMP it thought it was just another
> > NCP
> > connected host.  It'd set up a host output buffer and instead of doing a
> > hardware
> > "send" it'd pass control to the upper 16K.  Similarly [at least for the
> > TIP], when it
> > got something in from a terminal it'd copy it into a host-input buffer
> and
> > then
> > issue an "interrupt" down to the IMP.   Worked quite well.
> >
> >   /Bernie\
> >             Bernie Cosell
> >        bernie at fantasyfarm.com
> > -- Too many people; too few sheep --
> >
> >
> >
> >
> > --
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> > https://elists.isoc.org/mailman/listinfo/internet-history
> >
> --
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>

-- 
Geoff.Goodfellow at iconia.com
living as The Truth is True
http://geoff.livejournal.com