[Info-vax] CRTL and RMS vs SSIO

[Stephen Hoffman]

On 2021-10-12 14:54:37 +0000, Arne Vajhj said:

> On 10/12/2021 9:46 AM, Lawrence D’Oliveiro wrote:
>> On Tuesday, October 12, 2021 at 1:34:47 PM UTC+13, Arne Vajhøj
>> wrote:
>>> Getting VMS compilers, VMS language RTL, VMS RTL, RMS, VMS system 
>>> services and DCL working on Linux in a fully compatible manner would be 
>>> very tricky.
>> 
>> Still less than the ongoing costs of porting the whole of VMS onto new 
>> hardware.
> 
> I doubt that.

I also doubt that any kernel-swap will be less work. See my previous 
reply on that.

> There is really not that much ISA specific in an OS. VMS needs 
> Macro-32, Bliss, C VMS extensions etc. but they are needed by customers 
> anyway.

OpenVMS has had a whole lot of ISA dependencies over the years, but has 
been incrementally moving those dependencies from hardware or firmware 
into the kernel.

SWIS is where a whole lot of those VAX ISA dependencies now reside 
within OpenVMS.

>> Like revamping an antiquated driver model with no support for 
>> hotplugging, PCI-E, USB, iSCSI, Fibre Channel, 10G+ Ethernet, NUMA, 
>> GPGPU, scalability to thousands of processors ... all of which you 
>> would get for free.
> 
> VMS already supports USB, iSCSI, FC, 10G ethernet etc..

PCIe: supported on Itanium rx2660 and newer.

Thunderbolt: OpenVMS is just getting to hardware with that support.

USB: USB 2.0. Support for USB 3.0, 3.1, 3.2, and USB4 will likely need 
some work within OpenVMS.

iSCSI: not supported on OpenVMS past a now-abandoned software initiator 
prototype. Might eventually see an iSCSI hardware initiator HBA. Adding 
software (as was prototyped on OpenVMS) seems rather less likely.

FC: supported since Alpha, with yet-faster FC support added by VSI.

10GbE: supported. Support dates back a while, too.

40GbE: VSI is probably going to have to take a pretty good look at I/O 
latency for this, as has been discussed here in comp.os.vms in 
association with Linux I/O.

NUMA: supported on Alpha and newer. ~All of the big boxes booting 
OpenVMS are NUMA.

GPGPU / NPU / TPU / etc: not available with OpenVMS. whether Vulkan, 
CUDA, or ML acceleration or other such is interesting to OpenVMS folks?

Hot-plugging depends greatly on which devices or components are 
involved. There has been some support for hot-plugging and hot-adding 
some devices over the years, though that usually with hardware assists.

> CPU's may be limited to 64, but I don't think anyone will want more 
> (VMS is not for HPC).

Current-generation x86-64 processors (Milan) offer 64 cores and 128 
threads per socket.



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