7 ms·

How many computers are in your computer? (2021)

Sirened 4y ago
A favorite related to talk is Roscoe's keynote titled "It's Time for Operating Systems to Rediscover Hardware" [1] in which he discusses some of the outcomes/consequences of kernels (like Linux) largely sticking their heads in the sand on the issue of these massively heterogeneous SoCs. [1] https://www.youtube.com/watch?v=36myc8wQhLo https://www.youtube.com/watch?v=36myc8wQhLo
- pabs3 4y ago
  Did the talk offer any solutions to this? Its not like any of the secondary processors he could be talking about have any kind of open source support or even public specifications of their programmability or ISAs or similar.
  - Sirened 4y ago
    One of the key points he makes is that this is now an entrenched problem. SoC designers looked to Linux and asked "hey, can you drive the power management stuff?" and got no real help and so instead just built it out of the purview of the AP clusters altogether. Hardware is essentially implementing an abstract interface that is convenient for Linux to use and hiding everything else that's too difficult to add. The solution, and one that he specifically calls out, is that operating systems people need to work with hardware people to build better hardware and software together to build new computers. We got into this situation because everyone was just solving problems with the tools they readily had available to them. This is obviously easier said than done, but it does make now a very interesting time to work at one of those handful of large companies which produces their own custom SoCs and operating systems (I believe it's Apple, Google, and Microsoft) since you really have to take both operating systems and hardware forward simultaneously to solve the underlying issue.
    - loudmax 4y ago
      As I understand, this is the promise of Oxide Computer company. While they're not making their own SoCs, they are attempting to design the hardware and software together. Co-founder Bryan Cantrill has gone on rants about the number of extra layers of computers in your servers.
  - shp0ngle 4y ago
    What he says in the end is - you can just ask for the specs and often they give it to you. What I understand - currently there is not even a model of an "operating system" as such that would even consider those secondary processors.
    - PeterisP 4y ago
      This is a big security issue, because the operating system security model relies on assumptions that can be (and are) broken by these devices in ways that the OS can't control. The appropriate model would be exactly the one described in the original article above - explicitly treat the computer as a network of devices, and have the OS on the main CPU acknowledge that it is effectively sending a message to e.g. RAM over a shared network that also contains multiple other devices, potentially untrusted.
      - renox 4y ago
        This problem isn't new.. I remember Creative Sound cards hogging the PCI bus longer than their allocated time slice, a sure way to destabilise the entire computer. IMHO there's no solution, the only thing you can do is to select carefully the HW providers you use and do lots of tests..
      - pabs3 4y ago
        Linux already knows what firmware is and calls interfaces provided by firmware, so this isn't exactly a stretch for an OS model. The major issue is that all that firmware is proprietary and NDAs and patents block any OS or open source code from taking over the role of the proprietary firmware.
    - VLM 4y ago
      Well, there's MVS360 from awhile ago.
  - bobajeff 4y ago
    I think his main solution was for OS researchers to design their own hardware.
einpoklum 4y ago
Not convincing. This post: * Aggregates disparate devices (e.g. PC, smartphone and watch) * Mentions functional units which could theoretically be treated like a computer (e.g. Turing-complete) - but aren't a computer which acts independently. * Counts cores as different computers, but - either a core is a computer, or the system with multiple cores is a computer. The computation a multi-core system does is having one of its cores run. So basically, you'll be told about the on-Mobo chip for controlling its operations, and the Intel Management Engine and the AMD equivalent. Not worth the read IMHO.
- Sirened 4y ago
  I think the titular question is more rhetorical than actually attempting to give you a count. Lots of people do really think that there is one "computer" in their laptop when in fact the question of what a computer even is poses a way more difficult question. I loved the note on the MMU because it, aside from being a hilarious conference talk, poses the question of where we can even draw the line because clearly if the MMU can implement full programs than surely it's wrong to draw the line at the borders of a core on a SoC. Modern hardware is really funky and cool, and this article provides a good introduction to the chaos.
- PeterisP 4y ago
  And the quite capable computers that do things like being controllers for your hard drive, or wifi or other devices on your "computer" ? A relevant example is this article "Evil never sleeps" https://arxiv.org/abs/2205.06114 https://arxiv.org/abs/2205.06114 about the ability of those "secondary computers" to function without the cooperation of the primary computer, in this case the iPhone where they even work (sometimes maliciously) while the main device is "turned off".
  - einpoklum 4y ago
    Oh, yes, these definitely exist. There was even a paper a few years back in VLDB from Samsung about how they put un-utilized ARM cores from their disk controllers to do work off-loaded from a MySQL database.
vidarh 4y ago
This reminds me of my Amiga 2000, because it's the first time I became fascinated by the number of extra CPUs, because my A2000 setup was a bit weird. It had of course its main CPU, the 68000, and its CPU like copper. But it also had a 6502 compatible CPU controlling the keyboard. Then I put a SCSI controller in it that had a Z80 on it. And a 68020 accelerator board. Then I added a Janus PC card (the A2000 had an ISA bus in addition to the native bus and a Janus card let you run x86 PC software in a window on your Amiga desktop) with a 8086. Lastly I added a 286 accelerator to the PC side. Of course the original 68000 and 8086 were not active, but having 4 processor families in a single box was fun. Of course, this whole using Turing complete chips or whole CPUs other places than the main CPU is a much older thing. E.g. Commodore designs "borrowed" this from bigger computer systems when they put fully programmable 6502 based computers in their external floppy drives for their 8-bit line (you can load code into the memory of the 1541 floppy drive and execute it) The number of CPUs took a temporary dip in the PC world for a while with e.g. increasing use of dumb IDE controllers instead of SCSI controllers which at the time often had CPUs/microcontrollers on them. But it didn't take long before the upward trend in number of CPUs resumed.
- TacticalCoder 4y ago
  > E.g. Commodore designs "borrowed" this from bigger computer systems when they put fully programmable 6502 based computers in their external floppy drives for their 8-bit line (you can load code into the memory of the 1541 floppy drive and execute it) Yup Gwern mentions it in TFA. I had a Commodore 128 (well I still have it and it's still working!): Z80 chip in addition to the MOS ones (not just the CPU but the soundchip too). I'd say though that back then none of these chips were added due to committees being infiltrated by three letters agencies or their chinese equivalent with the goal of introducing backdoors.
  - rzzzt 4y ago
    Bil Herd mentions in a few re-tellings that the C128 had power problems when they tried to use the CP/M cartridge originally intended for the C64, so it got "absorbed" into the design instead.
- 4y ago
SkeuomorphicBee 4y ago
That reminds me of a blog post where the author managed to run Linux on an HDD, that is, not only using the HDD as the storage media for a Linux install, but instead running the kernel on the HDD's internal IO controller, SOC inside the HDD that actually runs the plates and everything. Unfortunately I could never find that post again, because all searches for running Linux on HDD return obvious results for using the HDD as an install media, not as the computer.
- MHordecki 4y ago
  Here: http://spritesmods.com/?art=hddhack&page=1 http://spritesmods.com/?art=hddhack&page=1
- cj 4y ago
  "install linux on hdd firmware" led me to this Reddit post: https://www.reddit.com/r/linux/comments/6059do/how_to_run_linux_on_your_hard_disk_firmware/ https://www.reddit.com/r/linux/comments/6059do/how_to_run_li... which links to this blog post: http://spritesmods.com/?art=hddhack&page=1 http://spritesmods.com/?art=hddhack&page=1
- sandos 4y ago
  I was amazed by the linux-running sdcards.
  - vidarh 4y ago
    You're thinking of the Transcend Wifi cards? [1] The ones running a web server and Perl CGI's.... [1] http://haxit.blogspot.com.au/2013/08/hacking-transcend-wifi-sd-cards.html http://haxit.blogspot.com.au/2013/08/hacking-transcend-wifi-...
- galangalalgol 4y ago
  The author left off peripherals too. There are microcontrollers that can be hacked in many mice, keyboards, and monitors. Anything that uses usb for more than power has at least a microcontroller, and anything that uses usb2 or later almost certainly has an arm processor in it.
moring 4y ago
Counterpoint re security issues: If the function of these separate computes like the HDD controller were running on the main CPU, they would have to be integrated in the same software stack; maybe as a driver in the OS, maybe as CPU-internal firmware, whatever. This doesn't just grow a software stack that is already insanely huge, it also introduces new issues because the HDD controller has to perform hard real-time tasks, adding even more complexity. It's also competing for time on the same processor, adding timing channels and other side-channels. I can't take this beyond a gut feeling, but that gut feeling tells me that separate "computers" are actually a good thing for security.
- tim333 4y ago
  If you are really worried about security like you have a private key protecting millions of dollars of bitcoin say, you are better really putting that on a separate 'computer' called a hardware wallet that isolates it from the general mess.
- 95014_refugee 4y ago
  I think “can be” rather than necessarily “are”, but yes; delegation like this enables more robust separation of concerns, in addition to explicit time / space separation. “Can be” because you have to be intentional about it. As the author implies, it’s easy to build multiple insecure computers, and when you call it “firmware” and hire people with “firmware” experience, this tends to negatively correlate with the security mindset…
jonatron 4y ago
Some cables have a computer in them [1] [2] [1] https://www.theregister.com/2013/03/04/cpu_inside_apple_video_adapter/ https://www.theregister.com/2013/03/04/cpu_inside_apple_vide... [2] https://www.chargerlab.com/two-arm-cpus-are-inside-teardown-of-apple-thunderbolt-4-pro-cable-3-m/ https://www.chargerlab.com/two-arm-cpus-are-inside-teardown-...
hydroid7 4y ago
The article doesn't mention people with computers in them...

A favorite related to talk is Roscoe's keynote titled "It's Time for Operating Systems to Rediscover Hardware" [1] in which he discusses some of the outcomes/consequences of kernels (like Linux) largely sticking their heads in the sand on the issue of these massively heterogeneous SoCs. [1] https://www.youtube.com/watch?v=36myc8wQhLo https://www.youtube.com/watch?v=36myc8wQhLo

pabs3 4y ago
Did the talk offer any solutions to this? Its not like any of the secondary processors he could be talking about have any kind of open source support or even public specifications of their programmability or ISAs or similar.
- Sirened 4y ago
  One of the key points he makes is that this is now an entrenched problem. SoC designers looked to Linux and asked "hey, can you drive the power management stuff?" and got no real help and so instead just built it out of the purview of the AP clusters altogether. Hardware is essentially implementing an abstract interface that is convenient for Linux to use and hiding everything else that's too difficult to add. The solution, and one that he specifically calls out, is that operating systems people need to work with hardware people to build better hardware and software together to build new computers. We got into this situation because everyone was just solving problems with the tools they readily had available to them. This is obviously easier said than done, but it does make now a very interesting time to work at one of those handful of large companies which produces their own custom SoCs and operating systems (I believe it's Apple, Google, and Microsoft) since you really have to take both operating systems and hardware forward simultaneously to solve the underlying issue.
  - loudmax 4y ago
    As I understand, this is the promise of Oxide Computer company. While they're not making their own SoCs, they are attempting to design the hardware and software together. Co-founder Bryan Cantrill has gone on rants about the number of extra layers of computers in your servers.
- shp0ngle 4y ago
  What he says in the end is - you can just ask for the specs and often they give it to you. What I understand - currently there is not even a model of an "operating system" as such that would even consider those secondary processors.
  - PeterisP 4y ago
    This is a big security issue, because the operating system security model relies on assumptions that can be (and are) broken by these devices in ways that the OS can't control. The appropriate model would be exactly the one described in the original article above - explicitly treat the computer as a network of devices, and have the OS on the main CPU acknowledge that it is effectively sending a message to e.g. RAM over a shared network that also contains multiple other devices, potentially untrusted.
    - renox 4y ago
      This problem isn't new.. I remember Creative Sound cards hogging the PCI bus longer than their allocated time slice, a sure way to destabilise the entire computer. IMHO there's no solution, the only thing you can do is to select carefully the HW providers you use and do lots of tests..
    - pabs3 4y ago
      Linux already knows what firmware is and calls interfaces provided by firmware, so this isn't exactly a stretch for an OS model. The major issue is that all that firmware is proprietary and NDAs and patents block any OS or open source code from taking over the role of the proprietary firmware.
  - VLM 4y ago
    Well, there's MVS360 from awhile ago.
- bobajeff 4y ago
  I think his main solution was for OS researchers to design their own hardware.

einpoklum 4y ago

Not convincing. This post: * Aggregates disparate devices (e.g. PC, smartphone and watch) * Mentions functional units which could theoretically be treated like a computer (e.g. Turing-complete) - but aren't a computer which acts independently. * Counts cores as different computers, but - either a core is a computer, or the system with multiple cores is a computer. The computation a multi-core system does is having one of its cores run. So basically, you'll be told about the on-Mobo chip for controlling its operations, and the Intel Management Engine and the AMD equivalent. Not worth the read IMHO.

Sirened 4y ago
I think the titular question is more rhetorical than actually attempting to give you a count. Lots of people do really think that there is one "computer" in their laptop when in fact the question of what a computer even is poses a way more difficult question. I loved the note on the MMU because it, aside from being a hilarious conference talk, poses the question of where we can even draw the line because clearly if the MMU can implement full programs than surely it's wrong to draw the line at the borders of a core on a SoC. Modern hardware is really funky and cool, and this article provides a good introduction to the chaos.
PeterisP 4y ago
And the quite capable computers that do things like being controllers for your hard drive, or wifi or other devices on your "computer" ? A relevant example is this article "Evil never sleeps" https://arxiv.org/abs/2205.06114 https://arxiv.org/abs/2205.06114 about the ability of those "secondary computers" to function without the cooperation of the primary computer, in this case the iPhone where they even work (sometimes maliciously) while the main device is "turned off".
- einpoklum 4y ago
  Oh, yes, these definitely exist. There was even a paper a few years back in VLDB from Samsung about how they put un-utilized ARM cores from their disk controllers to do work off-loaded from a MySQL database.

vidarh 4y ago

This reminds me of my Amiga 2000, because it's the first time I became fascinated by the number of extra CPUs, because my A2000 setup was a bit weird. It had of course its main CPU, the 68000, and its CPU like copper. But it also had a 6502 compatible CPU controlling the keyboard. Then I put a SCSI controller in it that had a Z80 on it. And a 68020 accelerator board. Then I added a Janus PC card (the A2000 had an ISA bus in addition to the native bus and a Janus card let you run x86 PC software in a window on your Amiga desktop) with a 8086. Lastly I added a 286 accelerator to the PC side. Of course the original 68000 and 8086 were not active, but having 4 processor families in a single box was fun. Of course, this whole using Turing complete chips or whole CPUs other places than the main CPU is a much older thing. E.g. Commodore designs "borrowed" this from bigger computer systems when they put fully programmable 6502 based computers in their external floppy drives for their 8-bit line (you can load code into the memory of the 1541 floppy drive and execute it) The number of CPUs took a temporary dip in the PC world for a while with e.g. increasing use of dumb IDE controllers instead of SCSI controllers which at the time often had CPUs/microcontrollers on them. But it didn't take long before the upward trend in number of CPUs resumed.

TacticalCoder 4y ago
> E.g. Commodore designs "borrowed" this from bigger computer systems when they put fully programmable 6502 based computers in their external floppy drives for their 8-bit line (you can load code into the memory of the 1541 floppy drive and execute it) Yup Gwern mentions it in TFA. I had a Commodore 128 (well I still have it and it's still working!): Z80 chip in addition to the MOS ones (not just the CPU but the soundchip too). I'd say though that back then none of these chips were added due to committees being infiltrated by three letters agencies or their chinese equivalent with the goal of introducing backdoors.
- rzzzt 4y ago
  Bil Herd mentions in a few re-tellings that the C128 had power problems when they tried to use the CP/M cartridge originally intended for the C64, so it got "absorbed" into the design instead.
4y ago

SkeuomorphicBee 4y ago

That reminds me of a blog post where the author managed to run Linux on an HDD, that is, not only using the HDD as the storage media for a Linux install, but instead running the kernel on the HDD's internal IO controller, SOC inside the HDD that actually runs the plates and everything. Unfortunately I could never find that post again, because all searches for running Linux on HDD return obvious results for using the HDD as an install media, not as the computer.

MHordecki 4y ago
Here: http://spritesmods.com/?art=hddhack&page=1 http://spritesmods.com/?art=hddhack&page=1
cj 4y ago
"install linux on hdd firmware" led me to this Reddit post: https://www.reddit.com/r/linux/comments/6059do/how_to_run_linux_on_your_hard_disk_firmware/ https://www.reddit.com/r/linux/comments/6059do/how_to_run_li... which links to this blog post: http://spritesmods.com/?art=hddhack&page=1 http://spritesmods.com/?art=hddhack&page=1
sandos 4y ago
I was amazed by the linux-running sdcards.
- vidarh 4y ago
  You're thinking of the Transcend Wifi cards? [1] The ones running a web server and Perl CGI's.... [1] http://haxit.blogspot.com.au/2013/08/hacking-transcend-wifi-sd-cards.html http://haxit.blogspot.com.au/2013/08/hacking-transcend-wifi-...
galangalalgol 4y ago
The author left off peripherals too. There are microcontrollers that can be hacked in many mice, keyboards, and monitors. Anything that uses usb for more than power has at least a microcontroller, and anything that uses usb2 or later almost certainly has an arm processor in it.

moring 4y ago

Counterpoint re security issues: If the function of these separate computes like the HDD controller were running on the main CPU, they would have to be integrated in the same software stack; maybe as a driver in the OS, maybe as CPU-internal firmware, whatever. This doesn't just grow a software stack that is already insanely huge, it also introduces new issues because the HDD controller has to perform hard real-time tasks, adding even more complexity. It's also competing for time on the same processor, adding timing channels and other side-channels. I can't take this beyond a gut feeling, but that gut feeling tells me that separate "computers" are actually a good thing for security.

tim333 4y ago
If you are really worried about security like you have a private key protecting millions of dollars of bitcoin say, you are better really putting that on a separate 'computer' called a hardware wallet that isolates it from the general mess.
95014_refugee 4y ago
I think “can be” rather than necessarily “are”, but yes; delegation like this enables more robust separation of concerns, in addition to explicit time / space separation. “Can be” because you have to be intentional about it. As the author implies, it’s easy to build multiple insecure computers, and when you call it “firmware” and hire people with “firmware” experience, this tends to negatively correlate with the security mindset…

jonatron 4y ago

Some cables have a computer in them [1] [2] [1] https://www.theregister.com/2013/03/04/cpu_inside_apple_video_adapter/ https://www.theregister.com/2013/03/04/cpu_inside_apple_vide... [2] https://www.chargerlab.com/two-arm-cpus-are-inside-teardown-of-apple-thunderbolt-4-pro-cable-3-m/ https://www.chargerlab.com/two-arm-cpus-are-inside-teardown-...

hydroid7 4y ago

The article doesn't mention people with computers in them...