4 ms·

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

by ffhhj 4y ago

punnerud 4y ago
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.
- magicalhippo 4y ago
  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.
- ffhhj 4y ago
  An SSD hard disk instead of SD card? Maybe such computer should use some sort of treadmill allocation.
magicalhippo 4y ago
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 https://browser.geekbench.com/v4/cpu/11296737
- ffhhj 4y ago
  Sure, but old computers managed to get things done with much lower resources. What really seems missing in old computers is memory.
  - magicalhippo 4y ago
    Sure but they had much lower resources all around. Why cripple a high-performance CPU by not having RAM?
    - ffhhj 4y ago
      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.
      - demindiro 4y ago
        > Imagine Windows 2000 never complaining about being out of memory. Just put a huge swap file on it.
        Sugimot0 4y ago
        Or use zram or zswap https://wiki.archlinux.org/title/Improving_performance#zram_or_zswap https://wiki.archlinux.org/title/Improving_performance#zram_...
      - teraflop 4y ago
        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.
      - magicalhippo 4y ago
        > 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-bandwith/ https://cacm.acm.org/magazines/2004/10/6401-latency-lags-ban... (view PDF, table 1)
  - 4y ago
numpad0 4y ago
I get it but no, not yet. No microSD card hacked to run DOSbox either.
t-3 4y ago
It would probably be far more practical and useful to run one with lots of RAM and no dedicated storage.

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

by ffhhj 4y ago

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

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.

magicalhippo 4y ago
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.
ffhhj 4y ago
An SSD hard disk instead of SD card? Maybe such computer should use some sort of treadmill allocation.

magicalhippo 4y ago

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 https://browser.geekbench.com/v4/cpu/11296737

ffhhj 4y ago
Sure, but old computers managed to get things done with much lower resources. What really seems missing in old computers is memory.
- magicalhippo 4y ago
  Sure but they had much lower resources all around. Why cripple a high-performance CPU by not having RAM?
  - ffhhj 4y ago
    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.
    - demindiro 4y ago
      > Imagine Windows 2000 never complaining about being out of memory. Just put a huge swap file on it.
      - Sugimot0 4y ago
        Or use zram or zswap https://wiki.archlinux.org/title/Improving_performance#zram_or_zswap https://wiki.archlinux.org/title/Improving_performance#zram_...
    - teraflop 4y ago
      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.
    - magicalhippo 4y ago
      > 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-bandwith/ https://cacm.acm.org/magazines/2004/10/6401-latency-lags-ban... (view PDF, table 1)
- 4y ago

numpad0 4y ago

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

t-3 4y ago

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