[Info-vax] openvms and xterm

[Dan Cross]

In article <v05v0g$4sr$1 at panix2.panix.com>,
Scott Dorsey <kludge at panix.com> wrote:
>Dan Cross <cross at spitfire.i.gajendra.net> wrote:
>>
>>That said, some of the greybeards have no idea (and I mean none
>>whatsoever) of how modern systems _actually_ work under the hood
>>themselves.  Those in glass houses....
>
>I am certainly in that category and believe me it absolutely terrifies me.
>It terrifies me even more that when I ask people how things work inside, 
>nobody else seems to know either!
>
>What worries me is that we have a generation of people who don't really care.
>Or maybe more than one generation.

It's not even that people don't care, it's that the entire thing
is so ridiculously complex that it's beyond the understanding of
a single person, and much of it is hidden from the OS, buried
under layers of firmware blobs running on hidden cores outside
of the visibility, let alone control, of an operating system.

Consider IO buses; these days, the dominant high-end peripheral
interconnect is PCIe, which uses a serial protocol over
differential pairs for signalling at the electrical layer.  But
that protocol is complex, and it runs at absurd speeds; small
variations in trace length matter.  To even begin to use it, the
link pairs must be "trained" to work out timing parameters for
signalling.  How does THAT happen?  It turns out, a hidden core
with a serious DSP usually does it for you.  How do you debug
that?  Long gone are the days of attaching some probes to a few
test points and seeing what the hell the bus is doing, let alone
understanding what this random IP inside the SoC complex is
doing.  Sometimes the system vendors don't even know; they got
the IP (and its firmware) from a third party themselves.

Just booting a system is ridiculous.  Most of it is punted to
vendor code running inside of UEFI or the BIOS or whatever.
Most of that is inscruitable.

	- Dan C.