Got it, thanks. So the 1600 slots is related to the 1536 ports you
previously mentioned. The problem with that calculation is that you
can't just take the 4 CPC's x 12 fanout slots = 48 I/O drawers. There's
nowhere near enough room for that many drawers - you'd have to stack
about 9 on top of each frame :)
It's not very clear in that Redbook, but see the chart on the bottom of
page 19, "Frames and cabling". z16 limit = 12 I/O drawers.
On 7/30/2023 9:25 AM, Jon Perryman wrote:
> On Saturday, July 29, 2023 at 12:18:04 PM PDT, Tom Brennan
<t...@tombrennansoftware.com> wrote:
Where does "1,600 PCIe slots" come from?
If I calculated max configurable PCIe slots correctly, 4 CPC drawers * 12 PCIe+
fanout adapters * 2 fanout ports per adapter * 16 PCIe+ slots in each drawer =
1,536 PCIe+ slots. Sorry that I couldn't remember the exact number but I also said
PCIe instead of PCIe+. PCIe by other manufactures comes in 8, 16 & 32 wires
(called lanes where each lane transmits 1 bit). I suspect that PCIe+ is 64 lanes
transmitting 64 bits simultaneously. These are beasts compared to PC PCIe slots but
the implementation is the same.
On page 22 of https://www.redbooks.ibm.com/redbooks/pdfs/sg248950.pdf
Fanouts
- Each CPC drawer supports up to 12 PCIe+ fanout adapters to connect to
the PCIe+ I/O drawers, and Integrated Coupling Adapter Short Reach
(ICA SR) coupling links:
– A 2-port Peripheral Component Interconnect Express (PCIe) 16 GBps I/O
fanout.
Each port supports one domain in the 16-slot PCIe+ I/O drawers
. – ICA SR1.1 and ICA SR PCIe fanouts for coupling links (two links of 8 GBps
each).
On Saturday, July 29, 2023 at 12:18:04 PM PDT, Tom Brennan
<t...@tombrennansoftware.com> wrote:
Where does "1,600 PCIe slots" come from?
On 7/29/2023 9:28 AM, Jon Perryman wrote:
2. Hardware does not make a mainframe. IBM z16 has PCIe and ram which are also
on every modern motherboard. IBM z16 chooses not to include other hardware
(e.g. SATA, IDE, WIFI and more). Motherboards choose not to have 1,600 PCIe
slots. IBM could allow PCIe graphics cards, mice, keyboards and more.
Essentially, IBM z16 and AMD Ryzen can implement the same hardware if there was
enough customer demand.
3. OS does not make a mainframe. Linux running on z16 doesn't make it mainframe
Linux. There's nothing stopping Linux from taking advantage of every z16
hardware feature (e.g. 1,600 PCIe slots) but no one is willing to build the
Linux software. IBM hasn't duplicated z/OS software features in Linux.
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