A burnt-out case?

OK, the title line is a bit of a liberty: does anyone know if RISC OS always launches on the same core of a multicore CPU? And if so, does this adversely affect life expectancy of the chip? Or is there a wear-levelling mechanism in these chips that rotates core usage systematically?

Wear-out mechanisms exist for very few semiconductor devices. OTTOMH, they are flash devices when being written (not when being read), LEDs, lasers, and highly stressed power transistors. Logic devices don’t have a wear-out mechansim AFAIK. Microprocessors have flash memory, but in the case we’re talking about, the flash is only being read. (You’d only write it if you were replacing the on-chip firmware – NOT to be confused with replacing the stuff on the SD card.)

Everything can, in theory, wear out.

However, some people still use their ARM3 machines, some their RiscPCs, and some, even, their BBC era hardware.
So we’re looking at around 30-35 years of use already for the ARM devices, and maybe 40 for the 6502.
I wouldn’t worry too much about overusing the processor on a Pi. What’s more likely to kill it is one of the following (in rough order to most likely to least):

• Bad power supply (too high voltage)
• Surges (either on the power input or induced in something connected to the GPIO)
• Overstressing it (overclocking too far, overheating)
• Thermal shock (running it hard and hot during the day, off at night)

In my case, I have an old under-laptop fan set up to suck air from the power brick and Pi and blow it towards the Vonets (keeping all that cooler), the Pi runs full tilt at the standard 900MHz and when idling steps down to 400MHz (gains a couple of extra degrees in the summer). It’s set to throttle at 50C. And it runs all the time.

What ended the Pi1 was getting the Pi2, which has been running ever since. If anything on that goes, it’s going to be the SD card (where things like wear levelling are important) rather than a core.

Keep it cool, keep it steady, you’ll be fine.

I don’t end a Pi1 because I’ve got a Pi2, I just move the older one to ever more inhospitable locations. My original Pi 1B 256MB has spent the last few years in the shed, varying between an ambient of -5C and 65C, and along with the Galaxy S (1st gen) charger powering it, refuses to die. I’ve even had to put it’s official Pi WiFi dongle back on as newer one with the high gain antenna started to get unreliable after the roasting in the summer.

I don’t end a Pi1 because I’ve got a Pi2,

It’s no “ended” permanently. I didn’t hit it with a hammer.
More like…the end of a reign.

It’s still here, just currently unused.

between an ambient of -5C and -65C

The f…? Your shed is a portal to Antarctica?

get unreliable after the roasting in the summer.

WiFi stuff runs hot. What destroyed my original Vonets was a hot summer day (can’t MIPS devices throttle before cooking themselves?).
The new improved Vonets runs hot, but I have a small fan for forced air cooling.

So as far as ARM chips are concerned, the consensus seems to be that they are long-lived items even if situated in the climatic extremity that Druck is pleased to refer to as his shed. I’ve owned all 4 Pi models to date and only had reliability issues when radically overclocking (but the Pi 1 runs happily at 900Mhz, the Pi 2 at 1000 and the 4 at 1800Mhz). I only briefly used a case, on the Pi 3, but abandoned it in favour of unenclosed vertical VESA mounting on the back of the monitor for all models. The Pi 4 runs between 55 and 64 deg.C despite having a HAT and no active or passive cooling and is set to throttle at 70 – it hasn’t hit this to date, but the onset of summer may change that of course – we shall see. I have no experience of MIPS.

the biggest part of the problem is outside the MIPS CPU,

Outside the CPU, yes. But in the same bit of silicon. Because…

It would be nice to see things like the Vonets bridges using a low end ARM though.

I agree, but somebody (Realtek, IIRC) has quite a line in reasonably capable MIPS SoCs with built in ethernet and WiFi. My 480p tilt and turn IPcam (the horribly insecure one) was also based around a MIPS SoC.

Hmm, I think my Livebox’s WiFi interface is some sort of mini-PCI card with a MIPS SoC on it.

I think that modern MIPS are able to throttle, and monitor tempurature

I would be surprised if it didn’t have some sort of temperature measurement. Whether or not the OS makes any use of it is another question.

I have no experience of MIPS.

I think in the case of the Vonets, it wasn’t the processor so much as the WiFi radio. I used to use a WiFi dongle ¹ on the PC (it clashed with the ESP32 serial so I switched to passing the PC via the Vonets) and that dongle used to run really hot.

¹ https://www.grosbill.com/4-selection_grosbill_cle_usb_wifi_n_300_mbps-129020-reseaux-carte_reseau_sans_fil

Oops, corrected it to -5C to +65C.

Oh, I thought maybe you had rented out some storage space to Pfizer.