Interesting that you have to program the size of wheel with a plug-in module
(different values in a PROM?) rather than with DIP switches which would
allow any size of wheel rather than one of a set of pre-configured sizes. I
bet there was a significant cumulative error if the wheel size was slightly
wrong. I wonder why the spoken instructions didn't include road
numbers/names, given that they are all read sequentially from the tape.
I suppose an enhancement would use instructions from a PROM, which would
allow any instructions for any route by playing generic phrases such as
"turn left", "turn right", "third exit", "at crossroads", "at T junction",
"at roundabout" etc in the correct sequence, from a route that was stored in
the PROM as distances between phrases and the phrases to be used.
That would make it more like a modern satnav, except using the car's
mileometer rather than GPS. It would still have the "one wrong turn and
you're fucked" restriction, but it would allow any route to be defined. I
suppose the limitation would be the cost of PROMs and
digital-analogue-converters in the early 70s.
Allowing a route to be defined on-the-fly would have to wait until the
advent of mesh-maps of the country and a postcode-to-grid-reference list,
and processing power to calculate the best route. I wonder if that
technology was available before GPS? Could they conceivably have had
something that was a satnav like a modern one in all respects apart from not
using GPS - so it could do the route-planning for any address, as long as it
knew where you were starting from and as long as you obeyed every single
instruction and didn't go wrong anywhere.
On Wednesday, 15 January 2020 13:05:51 UTC, NY wrote:
Don't wheels come in pre-configured sizes ?
DIP switched would have been a bit fidderley, they could have used a pot
or two of a multipole rotary wafer switch.
I'm beting any diversion or accident would have totally screwed the system.
How would the PROM have spoken other than access an 8 track tape perhaps.
Did they say how much the system costs.
Yes and how many journeys you could store on a PROM, and most
would know where they were going anyway.
Ordering a PROM in the 70s would probaly have been a wait 28 days for delivery too, even I remmber those days of long delivery times compared to todays.
I'd say the chances of that not going wrong would be slim at best.
Miss a turn at the round about go around again would screw things up,
stopping off for petrol or going to a service station.
We are talking 1971 here where a 256 bit prom cost over £20. Are you
aware of just how many 'bits' are required to store the sentance "turn
left" even when highly compressed? Not much change out of 8000 bits.
Slow audio quality DAC's where very cheap using just a resistive
network even in the 60's.
ADC's were another story ....
Yes - microsoft had crude best route MSDOS application in the early 80's
Yes - microsoft had crude best route MSDOS application in the early
80's, its name escapes me now though.
I'd forgotten about Autoroute. I used to have a copy, for planning routes.
You could draw a rectangle on the map to avoid all routes that passed
through that rectangle - to avoid the centre of a town, for example. I think
once GPS became available a laptop running it could be plugged into a
standalone GPS unit via RS-232 (pre-USB) to show your position on the map.
This was in the days when display resolutions were very poor - 320x240, or
640x480 if you were very rich.
I may still have a copy of Autroute Plus (before Microsoft broke it),
wether I have anything to read the media it's on or a machine to run
it is another matter. B-)
Not just route planning, I used it to plot the locations of foot &
mouth cases in 2001. (4 years before google maps appeared).
It was certainly a giant step in planning a journey, and was
originally an independent product. What really got to me was
that, despite the improvements, each version took a step
Each new release, whilst it may well have great new features,
seemed to throw out or screw up something from the previous
The comments below were written at a time when I was still
running 2000, but had seen 2005:
In earlier days you could run several alternative routes, and
have them displayed simultaneously. Not any more.
It used to be possible to store, and use at will, a set of quite
detailed profiles for different vehicles or driving styles. Not
Once upon a time the characteristics of a road could be edited.
Not any more.
You could avoid a particular road, not just an area. Not any
You could show or hide sets of pushpins as desired. Not any
I remain unconvinced that the developers had any real
understanding of what users actually wanted.
Chris J Dixon Nottingham UK
The Intel 1602 Bipolar PROM (256 * 8 bits) was released in 1970.
The Intel 1702 2k bit EPROM was introduced in September1971, shortly
followed in November 1971 by the first microprocessor, the 4 bit Intel 4004.
Interestingly both AMD and Intel were heavily into memory devices in the
early 70's, both to experiment with the process improvements required in
order to produce future complex microprocessors.
Who remembers AA personalised routes, supplied on demand between
any two locations? They comprised a number of standard sheets,
combined as necessary, containing turn-by-turn instructions with
adjacent strip maps.
IIRC, each page had an overall summary, such as, "Rural route
through pleasant countryside, falling to level terrain."
Chris J Dixon Nottingham UK
Indeed they were., which is what I meant by "...supplied on
My task on family trips was to provide the instructions from the
route, and I also used to log the trip, computing mileages and
averages as we went.
Chris J Dixon Nottingham UK
I remember them but IIRC they were best if read out by a passenger,
rather than being for a driver trying to navigate by them when alone.
For the latter, I used to write my own, in large print that could be
read at a glance while it was lying on the passenger seat. I also kept
the information to an absolute minimum, such as a road number and a
direction to turn.
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