We lost the Father of Computing, Alan Turing, on this day when he suicided
in 1954 (long story). Just imagine where computing would've been now...
Yes, there are various theories surrounding his death, such as a jealous
lover, the FBI knowing that he knew about Verona and could be compromised
as a result of his sexuality, etc. Unless they speak up (and they ain't),
we will never know.
Unix reference? Oh, that... No computable devices (read his paper), no
computers... And after dealing with a shitload of OSs in my career, I
daresay that there is no more computable OS than Unix. Sorry, penguins,
but you seem to require a fancy graphical interface these days, just like
Windoze.
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."
> From: Derek Fawcus <dfawcus+lists-tuhs(a)employees.org>
> my scan of it suggests that only the host part of the address which were
> extensible
Well, the division into 'net' and 'rest' does not appear to have been a hard
one at that point, as it later became.
> The other thing obviously missing in the IEN 28 version is the TTL
Yes... interesting!
> it has the DF flag in the TOS field, and an OP bit in the flags field
Yeah, small stuff like that got added/moved/removed around a lot.
> the CIDR vs A/B/C stuff didn't really change the rest.
It made packet processing in routers quite different; routing lookups, the
routing table, etc became much more complex (I remember that change)! Also in
hosts, which had not yet had their understanding of fields in the addresses
lobotomized away (RFC-1122, Section 3.3.1).
Yes, the impact on code _elsewhere_ in the stack was minimal, because the
overall packet format didn't change, and addresses were still 32 bits, but...
> The other bit I find amusing are the various movements of the port
> numbers
Yeah, there was a lot of discussion about whether they were properly part of
the internetwork layer, or the transport. I'm not sure there's really a 'right'
answer; PUP:
http://gunkies.org/wiki/PARC_Universal_Packet
made them part of the internetwork header, and seemed to do OK.
I think we eventually decided that we didn't want to mandate a particular port
name size across all transports, and moved it out. This had the down-side that
there are some times when you _do_ want to have the port available to an
IP-only device, which is why ICMP messages return the first N bytes of the
data _after_ the IP header (since it's not clear where the port field[s] will
be).
But I found, working with PUP, there were some times when the defined ports
didn't always make sense with some protocols (although PUP didn't really have
a 'protocol' field per se); the interaction of 'PUP type' and 'socket' could
sometimes be confusing/problemtic. So I personally felt that was at least as
good a reason to move them out. 'Ports' make no sense for routing protocols,
etc.
Overall, I think in the end, TCP/IP got that all right - the semantics of the
'protocol' field are clear and simple, and ports in the transport layer have
worked well; I can't think of any places (other than routers which want to
play games with connections) where not having ports in the internetwork layer
has been an issue.
Noel
> From: Derek Fawcus
> Are you able to point to any document which still describes that
> variable length scheme? I see that IEN 28 defines a variable length
> scheme (using version 2)
That's the one; Version 2 of IP, but it was for Version 3 of TCP (described
here: IEN-21, Cerf, "TCP 3 Specification", Jan-78 ).
> and that IEN 41 defines a different variable length scheme, but is
> proposing to use version 4.
Right, that's a draft only (no code ever written for it), from just before the
meeting that substituted 32-bit addresses.
> (IEN 44 looks a lot like the current IPv4).
Because it _is_ the current IPv4 (well, modulo the class A/B/C addressing
stuff). :-)
Noel
> From: Johnny Billquist
> It's a separate image (/netnix) that gets loaded at boot time, but it's
> run in the context of the kernel.
ISTR reading that it runs in Supervisor mode (no doubt so it could use the
Supervisor mode virtual address space, and not have to go crazy with overlays
in the Kernet space).
Never looked at the code, though.
Noel
On 2018-06-17 04:00, jnc(a)mercury.lcs.mit.edu (Noel Chiappa) wrote:
> > From: Johnny Billquist
>
> > It's a separate image (/netnix) that gets loaded at boot time, but it's
> > run in the context of the kernel.
>
> ISTR reading that it runs in Supervisor mode (no doubt so it could use the
> Supervisor mode virtual address space, and not have to go crazy with overlays
> in the Kernet space).
Yes. That rings a bell now that you mention it. Pretty sure you are correct.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
> From: Johnny Billquist
> incidentally have 18 data bits, but that is mostly ignored by all
> systems. I believe the KS-10 made use of that, though. And maybe the
> PDP-15.
The 18-bit data thing is a total kludge; they recycled the two bus parity
lines as data lines.
The first device that I know of that used it is the RK11-E:
http://gunkies.org/wiki/RK11_disk_controller#RK11-E
which is the same cards as the RK11-D, with a jumper set for 18-bit operation,
and a different clock crystal. The other UNIBUS interface that could do this
was the RH11 MASSBUS controller. Both were originally done for the PDP-15;
they were used with the UC15 Unichannel.
The KS10:
http://gunkies.org/wiki/KS10
wound up using the 18-bit RH11 hack, but that was many years later.
Noel
On 2018-06-16 04:00, Tom Ivar Helbekkmo<tih(a)hamartun.priv.no> wrote:
> Warner Losh<imp(a)bsdimp.com> writes:
>
>> It looks like retrobsd hasn't been active in the last couple of years
>> though. A cool accomplishment, but with some caveats. All the network
>> is in userland, not the kernel, for example.
> Isn't 2.11BSD networking technically in userland? I forget. Johnny?
No, networking in 2.11BSD is not in userland. But it's not a part of
/unix either. It's a separate image (/netnix) that gets loaded at boot
time, but it's run in the context of the kernel.
I'd have to go and check this if anyone wants details. It's been quite a
while since I was fooling around inside there. Or maybe someone else
remembers more details on how it integrates.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt(a)softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
> From: Clem Cole
> The 8 pretty much had a base price in the $30k range in the mid to late
> 60s.
His statement was made in 1977 (ironically, the same year as the Apple
II).
(Not really that relevant, since he was apparently talking about 'smart
homes'; still, the history of DEC and personal computers is not a happy one;
perhaps why that quotation was taken up.)
> Later models used TTL and got down to a single 3U 'drawer'.
There was eventually a single-chip micro version, done in the mid-70's; it
was used in a number of DEC word-processing products.
Noel
> From: Dave Horsfall <dave(a)horsfall.org>
>> one of the Watson's saying there was a probably market for
>> <single-digit> of computers; Ken Olsen saying people wouldn't want
>> computers in their homes; etc, etc.
> I seem to recall reading somewhere that these were urban myths... Does
> anyone have actual references in their contexts?
Well, for the Watson one, there is some controversy:
https://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_attribution
My guess is that he might actually have said it, and it was passed down orally
for a while before it was first written down. The thing is that he is alleged
to have said it in 1943, and there probably _was_ a market for only 5 of the
kind of computing devices available at that point (e.g. the Mark I).
> E.g. Watson was talking about the multi-megabuck 704/709/7094 etc
No. The 7094 is circa 1960, almost 20 years later.
> Olsens's quote was about the DEC-System 10...
Again, no. He did say it, but it was not about PDP-10s:
https://en.wikiquote.org/wiki/Ken_Olsen
"Olsen later explained that he was referring to smart homes rather than
personal computers." Which sounds plausible (in the sense of 'what he meant',
not 'it was correct'), given where he said it (a World Future Society
meeting).
Noel
