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Comment by ffhhj | Hacker News Reader

Is there some single board computer without RAM, but that allows addressing SSD space as such?

SD card and SSD's have a latency on the order of 500us, while even a Raspberry Pi 3 has a memory latency[1] of around 200ns. That's three orders of magnitude difference in latency, which would destroy performance.

In addition, memory bandwidth is still at least an order of magnitude higher.

[1]: https://browser.geekbench.com/v4/cpu/11296737

Sure, but old computers managed to get things done with much lower resources. What really seems missing in old computers is memory.

Sure but they had much lower resources all around. Why cripple a high-performance CPU by not having RAM?

SSD speeds will probably continue increasing, so removing RAM will take us about 20 years back to the past, with the difference that these will have seemingly "unlimited" memory. Imagine Windows 2000 never complaining about being out of memory.

> Imagine Windows 2000 never complaining about being out of memory.

Just put a huge swap file on it.

Or use zram or zswap

https://wiki.archlinux.org/title/Improving_performance#zram_...

Getting rid of DRAM would take us back a lot farther than 20 years. A typical desktop PC circa 2000 using PC133 RAM would have had a memory access latency in the tens of nanoseconds.

> SSD speeds will probably continue increasing, so removing RAM will take us about 20 years back to the past

I think you significantly overestimate how much they can reduce latency for SSDs. Keep in mind, even a 80286 from 1982 had a memory latency in the 200ns range[1].

[1]: https://cacm.acm.org/magazines/2004/10/6401-latency-lags-ban... (view PDF, table 1)

500 us is still 2.5 orders of magnitude slower than Commodore 64 from 1982

Old computers were vastly weaker in a lot of ways, but memory latency isn't one of those things. A 6502 was also hitting memory every few hundred nanoseconds.

You could make it work with Optane except oops that just got discontinued.

Wouldn’t that kill the SSD after some time?

HomeAssistant running SQLite on on a small cheap MicroSD card, kill it a couple of months.

Each memory cell have a lifespan of ≈ 1000 write cycles, if I remember correctly.

I've had Home Assistant running on the same 32GB SD card for over 3 years now, and the DB is several GB thanks to several very chatty Z-Wave devices. Zero issues so far. So it's not a given it'll die in a couple of months.

An SSD hard disk instead of SD card?

Maybe such computer should use some sort of treadmill allocation.

It would probably be far more practical and useful to run one with lots of RAM and no dedicated storage.

I get it but no, not yet. No microSD card hacked to run DOSbox either.

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