show/tell me about DEC hardware (and x86 memory management)

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > show/tell me about DEC hardware (and x86 memory management)

Radia: Jul 14, 2021; And someday, together.. We'll shine.

rjmccall posted:

op, the dec alpha has a fully weak memory ordering model which requires read barriers on atomic loads of objects even if all the subsequent loads from the object are value-dependent on the loaded pointer. intriguingly, it is my understanding that the weakness of the alpha's memory ordering model is purely theoretical, and all shipping alpha hardware in fact uses a stronger model which does guarantee that dependent loads will be properly ordered. nonetheless, because this is not architecturally guaranteed, any lock-free code must ensure that it uses proper barriers around atomic loads if it is ever ported to alpha. in principle, systems programming languages such as c and c++ would allow programmers to clearly state their requirements and then compile it optimally for the given platform, potentially avoiding load barriers when compiling for systems other than the alpha. unfortunately, inventing a sound formal definition of the concept of value-dependence that still admits reasonable optimizations in code that may not even be aware of the fact that it's carrying a dependency on an atomic load has proven to be an exceptionally tricky problem. even now, a full ten years after the introduction of atomics to c and c++, many compilers do not compile the so-called "consume" memory ordering optimally. this problem would be entirely defined away if processors were instead as overtly hostile as the theoretical but not actual memory ordering model of the dec alpha, op

# ¿ Jan 11, 2022 03:34

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# ¿ May 22, 2024 19:12

Radia: Jul 14, 2021; And someday, together.. We'll shine.

the turbo buttonj makes your computer faster, it's right there in the name

# ¿ Jan 17, 2022 22:09

Radia: Jul 14, 2021; And someday, together.. We'll shine.

i like when companies have their own fab. i dont have a good reason as to why. i think it's neat.

# ¿ Jan 18, 2022 02:35

Radia: Jul 14, 2021; And someday, together.. We'll shine.

Kazinsal posted:

Dave Cutler was lead on both VMS and NT and he fuckin hates unix with an ahabian passion

i gotta hear stories come ONNnn

# ¿ Feb 1, 2022 08:12

Radia: Jul 14, 2021; And someday, together.. We'll shine.

~Coxy posted:

just read UHH, probably

# ¿ Feb 3, 2022 01:00

Radia: Jul 14, 2021; And someday, together.. We'll shine.

I WILL read this in part because i hate myself

# ¿ Feb 3, 2022 05:50

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# ¿ May 22, 2024 19:12

Radia: Jul 14, 2021; And someday, together.. We'll shine.

eschaton posted:

want to give InterLisp-D a try on an emulated Xerox workstation?

set up an account online.interlisp.org and you even get a persistent workspace

the square-dance crew who used to come into the bar & grill across the street from my place, pre-COVID, used to include the last owners of Medley

I asked after them with one of the folks from the crew not too long before the pandemic, because I was hoping to acquire the InterLisp IP and release it; my understanding had been the person who owned it was a bit of an rear end, but eventually disposition fell on a relative who didn�t have their head up their rear end and who worked with a number of people to enable this to happen

it�s pretty awesome, and mostly a faithful representation of what it�s like to use on real hardware�any misrepresentation is in the near-instantaneous performance, compared to a 16-bit bitslice microcoded CPU whose architecture was derived from the Nova, or the slightly more abstract virtual machine built atop of it

incidentally, the emulation they�re using should also be able to run the Smalltalk and ViewPoint environments, I hope those can also be hosted and shared; Smalltalk in particular is such an amazing system to use, everything is right there and malleable like putty, even moreso on a Lisp Machine

holy hell

# ¿ Mar 23, 2022 02:39

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > show/tell me about DEC hardware (and x86 memory management)