On 12/18/2022 10:23 PM, John Levine wrote:
> According to robf...@gmail.com
>> On Sunday, December 18, 2022 at 8:02:06 PM UTC-5, Russell Wallace wrote:
>>> On Sunday, December 18, 2022 at 11:41:55 PM UTC, MitchAlsup wrote:
>>>> There are some things not worth arguing about. 8-bit bytes is one of those.
>>> Oh, indeed! There is a reason I wrote up my alternate architecture as an intellectual exercise in alternate history, not
>> as a proposal for something to actually build today.
>> I like the “what if” alternate reality thought experiments. One of my favorites is what
>> if the CPU had become popular 100 years earlier? It is not impossible. I think they
>> could have been made using diode-diode logic. Power consumption would be
> Eccles and Jordan invented the flip-flop in 1918 so, sure. De Forest
> invented the triode in 1906 so flip-flops could have been invented a
> decade earlier.
> I get the impression that for many decades it was considered a
> curiosity with little if any practical use. Only in the late 1930s did
> anyone start to build electronic logic.
Could have been amusing if there were a world where logic were built
using tiny hydraulic components.
Since the logic doesn't need to drive large cylinders, could use very
small hydraulic lines at low pressures.
Possibly all the hydraulic lines and valves could be made out of copper
and brass, using a lot of cast-brass components for all of the valves, ...
Brass would allow components to be cast in molds, and then soldered
together for final assembly.
Then, say, one has a small steam engine running the hydraulic pump (with
the hydraulic fluid then fed through a condenser).
Valves could be a mix multiply types, say:
Butterfly valves (for mechanical on/off);
Spool valves (like in traditional hydraulics);
Interference valves (using the shape of a valve cavity and turbulence
for logic, similar to a Tesla valve, *);
*: Say, a Tesla valve could function sort of like a hydraulic diode, but
would be unable to (completely) avoid back-flow.
Spool valves would have less issue with leakage or back-flow, but would
be harder to mass produce or miniaturize as effectively. In either case,
it would likely be more cost-effective to cast the parts out of brass
(likely using machined molds), rather than machining every valve housing
and spool on a lathe or similar.
Then, say, one knows if they have an improperly terminated connection,
because then all their data leaks out onto the floor...
Possibly data-connections look like bundles of small pipes with a
connector plate consisting of rows of holes, with a dense rubberized
separator/gasket. Data connections are then bolted together.
Possibly, say, read-only memory devices consist of spinning metal disks
or drums with holes drilled into them, with valves then used to gate the
data-bits through when the disk or drum rotates to the correct position.
Whether a bit is 1 or 0 depends mostly if (at the moment it is clocked
in) the line is connected to the supply or being let drain to the sump
(with the clock as an alternating supply/drain being driven by a
Not entirely sure what level of absurdity would be involved with trying
to build a register file or RAM out of hydraulic components. Seems like
for RAM, it might make sense to have the mass of valves representing the
memory device to essentially spin around as a drum (making connections
every time the drum rotates into a position where the holes line up).
Likely, a pair of lines could be used to signal Read or Write
operations, with the Read signal causing the drum to drive the outputs,
and the Write signal causing the drum to update its internal valves (at
that position) to whatever value is being driven on the data ports.
Possibly the memory bits are a bistable component, likely using a
rotating metal component and a latch/spring (driving the Write port
releases the latch, with the Read port allowed to drain to the sump,
where driving the bit causes it to turn to one position due to the
applied pressure, and no signal causes it to return to the other
position due to the spring; when no Write signal is asserted, the latch
prevents the valve from rotating, and driving the Read signal drives the
output bit based on whether the valve in question is in the open or
closed position at that moment).
External storage could be in the form of perforated tape (which then
either allows "sense pins" to push through the holes, or blocks the
sense pins, which in turn drive small hydraulic valves).
Seems like something like this could have possibly been built with early