3 ms·

Very interesting shift that happened over the last 2 decades. We likely haven't designed OSes or CPUs to match this new reality.

ajross 8y ago
Largely because it's not really a new reality. IBM faced the same issues on the 360's half a decade (edit: sorry, century!) ago -- you could stream data off of stacked platters in a drive into core much faster than a CPU could manage the copy. And the solution was to invent "I/O Channels", which were early DMA controllers. And the VM layer (when it was added) was cognizant of this stuff, so applications could be written directly to the channel interface. There's nothing new under the sun, basically. It's an Ecclesiastes design. I haven't read through the whole article, but my guess is that the "parakernel" interface the authors are positing is going to look a lot like the IBM Channel interface.
- drfuchs 8y ago
  I think you mean “half a century ago”.
- pjc50 8y ago
  Is there a good concise explanation of the 360 architecture available on the web? It seems historically important but I've not seen such a thing.
  - MagicPropmaker 8y ago
    Why, yes there is! The IBM 360 Principles of Operation. When I got my C.S. degree we spent a whole semester studying this. http://bitsavers.trailing-edge.com/pdf/ibm/360/princOps/A22-6821-0_360PrincOps.pdf http://bitsavers.trailing-edge.com/pdf/ibm/360/princOps/A22-...
    - stormbeard 8y ago
      This is a treasure trove of information; however, it's not what I would call concise. Did you run across anything else to supplement this during your program?
- deleted 8y ago
  [deleted]
- bhouston 8y ago
  Basically this I guess: https://en.wikipedia.org/wiki/Channel_I/O https://en.wikipedia.org/wiki/Channel_I/O
  - vvanders 8y ago
    Huh that's cool, kinda of makes me wonder if the SPE[1] in Cell is somewhat of a great-grandchild of Channel I/O. [1] https://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Synergistic_Processing_Elements_(SPE) https://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Syne...

ajross 8y ago

Largely because it's not really a new reality. IBM faced the same issues on the 360's half a decade (edit: sorry, century!) ago -- you could stream data off of stacked platters in a drive into core much faster than a CPU could manage the copy. And the solution was to invent "I/O Channels", which were early DMA controllers. And the VM layer (when it was added) was cognizant of this stuff, so applications could be written directly to the channel interface. There's nothing new under the sun, basically. It's an Ecclesiastes design. I haven't read through the whole article, but my guess is that the "parakernel" interface the authors are positing is going to look a lot like the IBM Channel interface.

drfuchs 8y ago
I think you mean “half a century ago”.
pjc50 8y ago
Is there a good concise explanation of the 360 architecture available on the web? It seems historically important but I've not seen such a thing.
- MagicPropmaker 8y ago
  Why, yes there is! The IBM 360 Principles of Operation. When I got my C.S. degree we spent a whole semester studying this. http://bitsavers.trailing-edge.com/pdf/ibm/360/princOps/A22-6821-0_360PrincOps.pdf http://bitsavers.trailing-edge.com/pdf/ibm/360/princOps/A22-...
  - stormbeard 8y ago
    This is a treasure trove of information; however, it's not what I would call concise. Did you run across anything else to supplement this during your program?
deleted 8y ago
[deleted]
bhouston 8y ago
Basically this I guess: https://en.wikipedia.org/wiki/Channel_I/O https://en.wikipedia.org/wiki/Channel_I/O
- vvanders 8y ago
  Huh that's cool, kinda of makes me wonder if the SPE[1] in Cell is somewhat of a great-grandchild of Channel I/O. [1] https://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Synergistic_Processing_Elements_(SPE) https://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Syne...