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IIRC, when you boot linux on a mainframe, you load your kernel and initrd into a virtual reader device so the machine can load it in 80-column punchcard sized c

IIRC, when you boot linux on a mainframe, you load your kernel and initrd into a virtual reader device so the machine can load it in 80-column punchcard sized chunks.

projektfu 3y ago
And on the PDP-10, it contains a virtual robot to toggle the virtual switches on the virtual PDP-11, to load a loader that runs the virtual tape drive to load the startup program for the PDP-10. j/k I have no idea how linux boots on Z.
- cbm-vic-20 3y ago
  This actually isn't too far from the truth. The VAX 8800 series of minicomputers used a cut-down PDP-11 to boot it, and to act as a console. https://en.wikipedia.org/wiki/VAX_8000#VAX_Console https://en.wikipedia.org/wiki/VAX_8000#VAX_Console
rbanffy 3y ago
Fun to think that it’s more or less how zVM starts stuff. It took me a while to mentally accept the concept of VM that zVM (in reality, I was playing with VM/370) has, which is not like anything non-mainframe users would be familiar with. But you can also run Linux directly on an LPAR under the thin hypervisor (which I forgot the name) that runs zVM. The indignity of the mainframe is that it’s booted under control of an x86 machine that itself boots up as an 8086. At least these days the service elements run Linux.
- skissane 3y ago
  > But you can also run Linux directly on an LPAR under the thin hypervisor (which I forgot the name) that runs zVM. The name is PR/SM - which, from what I’ve heard, actually started life as a modified version of VM > The indignity of the mainframe is that it’s booted under control of an x86 machine that itself boots up as an 8086. At least these days the service elements run Linux. Poor OS/2, no more booting mainframes for it anymore, unless they are very old ones
  - rbanffy 3y ago
    > Poor OS/2, no more booting mainframes for it anymore, unless they are very old ones At least it's not Windows.

IIRC, when you boot linux on a mainframe, you load your kernel and initrd into a virtual reader device so the machine can load it in 80-column punchcard sized chunks.

projektfu 3y ago

And on the PDP-10, it contains a virtual robot to toggle the virtual switches on the virtual PDP-11, to load a loader that runs the virtual tape drive to load the startup program for the PDP-10. j/k I have no idea how linux boots on Z.

cbm-vic-20 3y ago
This actually isn't too far from the truth. The VAX 8800 series of minicomputers used a cut-down PDP-11 to boot it, and to act as a console. https://en.wikipedia.org/wiki/VAX_8000#VAX_Console https://en.wikipedia.org/wiki/VAX_8000#VAX_Console

rbanffy 3y ago

Fun to think that it’s more or less how zVM starts stuff. It took me a while to mentally accept the concept of VM that zVM (in reality, I was playing with VM/370) has, which is not like anything non-mainframe users would be familiar with. But you can also run Linux directly on an LPAR under the thin hypervisor (which I forgot the name) that runs zVM. The indignity of the mainframe is that it’s booted under control of an x86 machine that itself boots up as an 8086. At least these days the service elements run Linux.

skissane 3y ago
> But you can also run Linux directly on an LPAR under the thin hypervisor (which I forgot the name) that runs zVM. The name is PR/SM - which, from what I’ve heard, actually started life as a modified version of VM > The indignity of the mainframe is that it’s booted under control of an x86 machine that itself boots up as an 8086. At least these days the service elements run Linux. Poor OS/2, no more booting mainframes for it anymore, unless they are very old ones
- rbanffy 3y ago
  > Poor OS/2, no more booting mainframes for it anymore, unless they are very old ones At least it's not Windows.