4 ms·

What I get from this is that a major method of rent seeking used by disk manufacturers, to differentiate expensive enterprise disk from cheap consumer disk, was

by nurple 3y ago

What I get from this is that a major method of rent seeking used by disk manufacturers, to differentiate expensive enterprise disk from cheap consumer disk, was colluding to keep the simple and effective write queue reporting from being shipped to the latter. It didn't require nvram, or complex microcode that knew how to process leftover wire requests, it only had to report back when each chunk it was already tracking in its buffers got persisted. To me it sounds like it's the manufacturers were the true partners in crime here.

dan-robertson 3y ago
The article is from 10 years ago. Most people use flash now which is different (see eg https://dl.acm.org/doi/pdf/10.1145/3064176.3064187 https://dl.acm.org/doi/pdf/10.1145/3064176.3064187). I think higher prices for enterprise-grade disks are more about reliability than NCQ behaviour.
- jacquesm 3y ago
  Try doing long, sustained out-of-order writes and see how long you can keep that up before you're down to very low transfer rates.
  - walth 3y ago
    Can you point me to any further specifics on this?
    - jacquesm 3y ago
      Essentially it will work fantastically until you hit the capacity of the cache memory and then the write rate will drop, sometimes only a bit, more often quite a lot. There are drives that can maintain their write rate 'forever', but those are substantially more expensive, for instance the Samsung 970 pro, see this graph from a Tom's Hardware article, it's a good graph because it very clearly shows how much cache the drives have and then it's game over: https://cdn.mos.cms.futurecdn.net/V5reyvV4UAwHxEMQBP2XWS-970-80.png.webp https://cdn.mos.cms.futurecdn.net/V5reyvV4UAwHxEMQBP2XWS-970... A review of that drive: https://www.tomshardware.com/reviews/samsung-970-pro-ssd-review,5572-2.html https://www.tomshardware.com/reviews/samsung-970-pro-ssd-rev...
olavgg 3y ago
This remains relevant today, as when a new SSD undergoes evaluation by a prominent website, the tests are typically limited to workloads for which the SSD is specifically designed. If the benchmarks included synchronous write and write latency assessments, the results would present a markedly different narrative. There are SSDs in the market whose write speeds are comparable to those of traditional spinning hard drives. Here is a barchart from some of the older Samsung SSD's https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0-77040600-1496968848.png https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0... https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0-53256900-1496968849.png https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0...
- moffkalast 3y ago
  Well the Intel S3500 sells for about $340 while the EVO 750 goes for about $40 for the same 0.5 TB size. I guess you get what you pay for.
- justsomehnguy 3y ago
  It's even worse now, because QLC. As soon as you deplete the SLC cache you are down to ~50MB/s
fragmede 3y ago
I'm all for throwing the corporations against the wall when the revolution comes, but charging money for features isn't rent seeking. Charging for support contracts, sure, but selling product Y for $Z, and Y+, which has more features, for $Z+ isn't.
- XorNot 3y ago
  There is a reasonable statement to be made that given the importance of computerized information to our modern world, regulation to enforce minimum capability and behavior is highly warranted however. We do the same thing for automobiles - which have diverse value-add feature sets, but for which we've pushed the average safety level consistently up due to their important and ubiquity.
  - thfuran 3y ago
    In the process we've made cars huge and hugely expensive, so it's not all roses.
    - XorNot 3y ago
      Car size has not been increasing because of safety regulations. It's been increasing because the American market demands it...and also only in the American market. The rest of the world buys reasonably sized vehicles well served by the automakers.
      - thfuran 3y ago
        >Car size has not been increasing because of safety regulations Not exclusively, no. But a regulatory regime considering only occupants' safety and not the safety of the other party in crashes is inherently biased towards larger vehicles. And various other regulations favor large SUVs/trucks over cars, from historical fuel efficiency rules to more recent depreciation schedules.
      - thworp 3y ago
        No. A BMW 5-series from the 80s is about the same size as a 2023 3-series. Almost every manufacturer I can think of has been doing this and in all market segments. VW had the compact Golf, the subcompact Polo and the even more compact Up!. The last Up! model is about the same size as the first Polo and the latest Polo same size as first Golf (both also from the 80s). Of course that growth rate is still nothing compared to some pickup/off-road models. Every time I'm in NA I am shocked by the size of these behemoths. The crazy part is that more and more people are buying these things in my corner of Europe, preferably if they live in an old village with roads that are barely 2m wide per lane. Some of these child decapitators have worse visibility and maneuverability than (EU) trucks. Ffs, if an 8-year old runs infront of your F250's grille they become invisible. This would be a valuable area of regulation imo, instead of mandatory speed limiters and breathalizers.

by nurple 3y ago

dan-robertson 3y ago

The article is from 10 years ago. Most people use flash now which is different (see eg https://dl.acm.org/doi/pdf/10.1145/3064176.3064187 https://dl.acm.org/doi/pdf/10.1145/3064176.3064187). I think higher prices for enterprise-grade disks are more about reliability than NCQ behaviour.

jacquesm 3y ago
Try doing long, sustained out-of-order writes and see how long you can keep that up before you're down to very low transfer rates.
- walth 3y ago
  Can you point me to any further specifics on this?
  - jacquesm 3y ago
    Essentially it will work fantastically until you hit the capacity of the cache memory and then the write rate will drop, sometimes only a bit, more often quite a lot. There are drives that can maintain their write rate 'forever', but those are substantially more expensive, for instance the Samsung 970 pro, see this graph from a Tom's Hardware article, it's a good graph because it very clearly shows how much cache the drives have and then it's game over: https://cdn.mos.cms.futurecdn.net/V5reyvV4UAwHxEMQBP2XWS-970-80.png.webp https://cdn.mos.cms.futurecdn.net/V5reyvV4UAwHxEMQBP2XWS-970... A review of that drive: https://www.tomshardware.com/reviews/samsung-970-pro-ssd-review,5572-2.html https://www.tomshardware.com/reviews/samsung-970-pro-ssd-rev...

olavgg 3y ago

This remains relevant today, as when a new SSD undergoes evaluation by a prominent website, the tests are typically limited to workloads for which the SSD is specifically designed. If the benchmarks included synchronous write and write latency assessments, the results would present a markedly different narrative. There are SSDs in the market whose write speeds are comparable to those of traditional spinning hard drives. Here is a barchart from some of the older Samsung SSD's https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0-77040600-1496968848.png https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0... https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0-53256900-1496968849.png https://www.diskusjon.no/uploads/monthly_06_2017/post-5591-0...

moffkalast 3y ago
Well the Intel S3500 sells for about $340 while the EVO 750 goes for about $40 for the same 0.5 TB size. I guess you get what you pay for.
justsomehnguy 3y ago
It's even worse now, because QLC. As soon as you deplete the SLC cache you are down to ~50MB/s

fragmede 3y ago

I'm all for throwing the corporations against the wall when the revolution comes, but charging money for features isn't rent seeking. Charging for support contracts, sure, but selling product Y for $Z, and Y+, which has more features, for $Z+ isn't.

XorNot 3y ago
There is a reasonable statement to be made that given the importance of computerized information to our modern world, regulation to enforce minimum capability and behavior is highly warranted however. We do the same thing for automobiles - which have diverse value-add feature sets, but for which we've pushed the average safety level consistently up due to their important and ubiquity.
- thfuran 3y ago
  In the process we've made cars huge and hugely expensive, so it's not all roses.
  - XorNot 3y ago
    Car size has not been increasing because of safety regulations. It's been increasing because the American market demands it...and also only in the American market. The rest of the world buys reasonably sized vehicles well served by the automakers.
    - thfuran 3y ago
      >Car size has not been increasing because of safety regulations Not exclusively, no. But a regulatory regime considering only occupants' safety and not the safety of the other party in crashes is inherently biased towards larger vehicles. And various other regulations favor large SUVs/trucks over cars, from historical fuel efficiency rules to more recent depreciation schedules.
    - thworp 3y ago
      No. A BMW 5-series from the 80s is about the same size as a 2023 3-series. Almost every manufacturer I can think of has been doing this and in all market segments. VW had the compact Golf, the subcompact Polo and the even more compact Up!. The last Up! model is about the same size as the first Polo and the latest Polo same size as first Golf (both also from the 80s). Of course that growth rate is still nothing compared to some pickup/off-road models. Every time I'm in NA I am shocked by the size of these behemoths. The crazy part is that more and more people are buying these things in my corner of Europe, preferably if they live in an old village with roads that are barely 2m wide per lane. Some of these child decapitators have worse visibility and maneuverability than (EU) trucks. Ffs, if an 8-year old runs infront of your F250's grille they become invisible. This would be a valuable area of regulation imo, instead of mandatory speed limiters and breathalizers.