Star Trek used the fictional "gigaquad" unit of computer data storage, and conveniently deliberately avoided defining how many bits the base unit of a "quad" is, so they never would get embarrassed if such an amount of storage became commonplace nowadays.
"an OS that behaves like a real computer that you can put on an old/cheap commodity phone": https://postmarketos.org/
"an app that creates a programmable environment layered over and isolated from the suffocating mobile OS": Android Virtualization Framework (AVF) on newer Android versions provides a hypervisor and a hardware-accelerated graphics (VirGL) for AVF virtual machines, allowing users to run an isolated Linux GUI desktop with low overhead.
With more bits, then SUB is going to be more and more expensive to fit in the same number of clocks as XOR. So with an 8-bit CPU like Z80, it probably makes design sense to have XOR and SUB both take one cycle. But if for instance a CPU uses 128-bit registers, then the propagate-and-carry logic for ADD/SUB might take way much longer than XOR that the designers might not try to fit ADD/SUB into the same single clock cycle as XOR, and so might instead do multi-cycle pipelined ADD/SUB.
A real-world CPU example is the Cray-1, where S-Register Scalar Operations (64-bit) take 3 cycles for ADD/SUB but still only 1 cycle for XOR. [1]
Some old guitar effects used -9V DC.[1] And the convention with guitar effects power adapter is the barrel is center negative (which is motivated with facilitating easy wiring of the socket's switch to connect to a 9V battery inside).
It depends. Many modern microcontrollers are perfectly fine driving LEDs directly off IO pins if the pin specs say it is rated for sufficient current (like 20mA). However, older ones like ESP8266 can only do like 2mA and the 8051 even less. Or you run into a total power budget issue if your are running too many pins. Also, some IO pins are perfectly fine at sinking current to ground but aren't suited for sourcing current, in which case the LED would be directly connected to an external high voltage and the IO pin would simply be switching to ground or not.
I don't think the prevalence of these articles this time of year is because the authors go on holiday, but instead is because the new year is the perfect time to ponder: "Will this be the year of the Linux desktop?"
Looking at the complexity and area of hardware floating point, I often wonder why we don't see more unified combined integer+floating point units, like done in the R4200 [1], which reused most of the integer datapath while just adding a smaller extra smaller 12-bit datapath for the exponent.
If you use a tile-based hardware renderer, such as on the original nintendo chip, then pixels are rendered on the fly to the screen by the hardware automatically pulling pixels based on the tile map.