2 Aug
2018
2 Aug
'18
12:44 p.m.
A tangential connection to early Unix experience:
My collection of early computer manuals includes Brinch Hansen's manual
for the RC 4000, which stands out for its precise description of the
CPU logic--in Algol 60! It's the only manual I have seen that offers a
good-to-the-last-bit formal description of the hardware.
DEC presented something of the sort for the PDP-11, but punted where
the woods got thick. When I wanted to know how they computed the last
bit of floating-point results, I got no satisfaction. Amidst a thorough
description of addressing came this formulation of the actual computation:
"form floating point result".
Doug
2 Aug
2 Aug
1:10 p.m.
New subject: In Memoriam: Per Brinch Hansen
Is this a weblink to that manual?
I want to read something so well written:)
Ben
https://pdfs.semanticscholar.org/b77f/02dedb784a52229c5376277173c5ef6da5c1.…
On Aug 2, 2018, at 8:44 AM, Doug McIlroy
<doug(a)cs.dartmouth.edu> wrote:
A tangential connection to early Unix experience:
My collection of early computer manuals includes Brinch Hansen's manual
for the RC 4000, which stands out for its precise description of the
CPU logic--in Algol 60! It's the only manual I have seen that offers a
good-to-the-last-bit formal description of the hardware.
DEC presented something of the sort for the PDP-11, but punted where
the woods got thick. When I wanted to know how they computed the last
bit of floating-point results, I got no satisfaction. Amidst a thorough
description of addressing came this formulation of the actual computation:
"form floating point result".
Doug
2:07 p.m.
New subject: In Memoriam: Per Brinch Hansen
I suspect not, I suspect his first reference is the one you want.
On Thu, Aug 02, 2018 at 09:10:54AM -0400, Ben Greenfield via TUHS wrote:
Is this a weblink to that manual?
I want to read something so well written:)
Ben
https://pdfs.semanticscholar.org/b77f/02dedb784a52229c5376277173c5ef6da5c1.…
> On Aug 2, 2018, at 8:44 AM, Doug McIlroy <doug(a)cs.dartmouth.edu> wrote:
>
> A tangential connection to early Unix experience:
>
> My collection of early computer manuals includes Brinch Hansen's manual
> for the RC 4000, which stands out for its precise description of the
> CPU logic--in Algol 60! It's the only manual I have seen that offers a
> good-to-the-last-bit formal description of the hardware.
>
> DEC presented something of the sort for the PDP-11, but punted where
> the woods got thick. When I wanted to know how they computed the last
> bit of floating-point results, I got no satisfaction. Amidst a thorough
> description of addressing came this formulation of the actual computation:
> "form floating point result".
>
> Doug
--
---
Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
3:44 p.m.
New subject: In Memoriam: Per Brinch Hansen
I think it is this one:
http://bitsavers.org/pdf/regnecentralen/RC_4000_Reference_Manual_Jun69.pdf
Along these lines, at least one of Fujitsu’s high end network switches was described using
PowerPoint slides. At one point while working for them I felt a software simulator of the
switch would really help with testing switch software. So I started developing one on my
own. That is when I discovered these slides were not only very detailed but also very
accurate and quite clear. They answered every question I had during the development. I
have never seen such /engineering/ use of PowerPoint anywhere else.
On Aug 2, 2018, at 7:07 AM, Larry McVoy
<lm(a)mcvoy.com> wrote:
I suspect not, I suspect his first reference is the one you want.
On Thu, Aug 02, 2018 at 09:10:54AM -0400, Ben
Greenfield via TUHS wrote:
Is this a weblink to that manual?
I want to read something so well written:)
Ben
https://pdfs.semanticscholar.org/b77f/02dedb784a52229c5376277173c5ef6da5c1.…
> On Aug 2, 2018, at 8:44 AM, Doug McIlroy <doug(a)cs.dartmouth.edu> wrote:
>
> A tangential connection to early Unix experience:
>
> My collection of early computer manuals includes Brinch Hansen's manual
> for the RC 4000, which stands out for its precise description of the
> CPU logic--in Algol 60! It's the only manual I have seen that offers a
> good-to-the-last-bit formal description of the hardware.
>
> DEC presented something of the sort for the PDP-11, but punted where
> the woods got thick. When I wanted to know how they computed the last
> bit of floating-point results, I got no satisfaction. Amidst a thorough
> description of addressing came this formulation of the actual computation:
> "form floating point result".
>
> Doug
--
---
Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
5 Aug
5 Aug
11:18 p.m.
New subject: In Memoriam: Per Brinch Hansen
On Thu, 02 Aug 2018 08:44:56 -0400 Doug McIlroy
<doug(a)cs.dartmouth.edu> wrote:
A tangential connection to early Unix experience:
My collection of early computer manuals includes Brinch Hansen's
manual for the RC 4000, which stands out for its precise
description of the CPU logic--in Algol 60! It's the only manual I
have seen that offers a good-to-the-last-bit formal description of
the hardware.
DEC presented something of the sort for the PDP-11, but punted where
the woods got thick. When I wanted to know how they computed the
last bit of floating-point results, I got no satisfaction. Amidst a
thorough description of addressing came this formulation of the
actual computation: "form floating point result".
For those that are familiar with the RISC V architecture, there's a
formal specification of the architecture that was done in a system
built on Coq, and also a fully formally verified translation of the
specification into RTL. (The spec didn't include floating point as of
about a year ago but it may by now.)
A good overview of the system involved is here:
http://plv.csail.mit.edu/kami/papers/icfp17.pdf
Followups might belong on the coff list, not sure.
Perry
--
Perry E. Metzger perry(a)piermont.com
2094
days inactive
2097
days old
4 comments
5 participants
participants (5)
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Bakul Shah -
Ben Greenfield -
Doug McIlroy -
Larry McVoy -
Perry E. Metzger