[Simh] Win32 Development Binaries?

[Christian Gauger-Cosgrove]

I've been busy as all heck with university coursework, so I've let my
hobbies languish. But I'm finally getting some free time, so I decided
to grab the latest SIMH build.

Any chance someone could restart the weekly dev builds again? Since
the pre-built binary distribution I see is from November 15th, 2014
(built from commit 368A5F6).

Cheers,
Christian

-- 
Christian M. Gauger-Cosgrove
STCKON08DS0
Contact information available upon request.
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[Simh] One last LGP-30/21 question - testing document available?

[B Degnan]

Just curiouslast message in a bottle on the subject of the LGP SIMH: 

I know that the SIMH for the LGP-21/30 was made official, so I assume there 
was a test process to approve and confirm that one could load and run the 
bootstrap and perform tape operations.  Can this test be made available?  
Perhaps someone more closely involved in this project will have a 
clue/communique from the past that details the process undergone to make 
this SIMH build "official".  With this I might be able to create the 
software others can download to run LGP on SIMH. 

I am pretty much convinced that the bootstrap instructions need to be 
entered in 8 character binary format.  There does not appear to be a 
pre-loaded bootstrap.  What I have not yet determined for sure are the 
Flexowriter equivalent command keys.  I have found program listings with 
lines like "0gwc" and I can only guess this is shorthand for a 
combination line containing routine flexo-hex and program mnemonic 
instructions.   

Regardless, I will keep at it as I have been making progress.   

Thanks in advance. 

Bill Degnan

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Re: [Simh] A terminology question

[Leo Broukhis]

In this case the value is calculated from the other bits:
parity({upper half-word, parity bit 1}) = 0, parity({lower half-word,
parity bit 2}) = 1 indicates an instruction word

parity({upper half-word, parity bit 1}) = 1, parity({lower half-word,
parity bit 2}) = 0 indicates a data word

Leo

On Wed, Feb 11, 2015 at 10:48 AM, Phil Budne  wrote:

> Leo wrote:
> > "Parity" makes the most sense. I was wondering if there is already a more
> > specific term for such a scheme.
>
> To me, parity implies value calculated from the other bits.
> "tag" or "attribute" bits ring better in my ears.  If the tag bits
> can't be tweaked by user code, the term "capability" might be a
> choice.
>
> Phil
>
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Re: [Simh] A terminology question

[Phil Budne]

Leo wrote:
> "Parity" makes the most sense. I was wondering if there is already a more
> specific term for such a scheme.

To me, parity implies value calculated from the other bits.
"tag" or "attribute" bits ring better in my ears.  If the tag bits
can't be tweaked by user code, the term "capability" might be a
choice.

Phil
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Re: [Simh] A terminology question

[Leo Broukhis]

That's right. An attempt to execute a word with anything but "command
convolution" results in an exception. There were system calls ("extracodes"
in BESM-6 parlance) to store individual words as instructions and to switch
store mode back and forth.

Leo

On Wed, Feb 11, 2015 at 12:23 AM, Pontus Pihlgren 
wrote:

> If I understand it correctly, you have four combinations:
>
> 11 -- illegal
> 10 -- data
> 01 -- instruction
> 00 -- illegal
>
> And memory locations market illegal or data wont be executed?
>
> This reminds me of the more modern terms "DEP" - Data Execution
> Prevention, "NX" - No-eXecute, "XD" - eXecute Disable, "XN" - eXecute
> Never. DEP and NX seems to be a generic terms and the others are
> platform specific. Different OSs that take advantage of this calls it
> different things.
>
> Not quite the same as the DEP is usually enforced on memory pages.
>
> /P
>
> On Mon, Feb 09, 2015 at 12:32:47PM -0800, Leo Broukhis wrote:
> > Dear colleagues,
> >
> > There is an implementation detail in the BESM-6 architecture the name of
> > which we've struggled to translate adequately.  There is a feature
> > preventing execution of arbitrary data as instructions implemented using
> > two parity bits per word, for the upper and the lower half-word. The
> > overall parity must be odd, and one of the valid parity bit
> configurations
> > denotes an instruction, and the other denotes data. In the original
> > documentation this mechanism was called
> >
> https://translate.google.com/#ru/en/%D1%81%D0%B2%D0%B5%D1%80%D1%82%D0%BA%D0%B0
> > (the two forms were called literally "command convolution" and "number
> > convolution").
> >
> > Unlike a tagged architecture, there isn't a fixed tag value to indicate
> > instructions or data.
> >
> > Is there a standard term for this? "Convolution" sounds too mathematical.
> >
> > Thanks,
> > Leo
>
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> > http://mailman.trailing-edge.com/mailman/listinfo/simh
>
>
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Re: [Simh] A terminology question

[Leo Broukhis]

Hi Tim,

"Parity" makes the most sense. I was wondering if there is already a more
specific term for such a scheme.

Thanks,
Leo

On Wed, Feb 11, 2015 at 4:35 AM, Shoppa, Tim  wrote:

>  Rather than "convolution", maybe "parity", "check", "hash", or
> "fingerprint"? Like "command parity" and"number parity" plus two "invalid
> parities"?
>
> Many buses have multiple parity bits already (e.g. "address parity" and
> "instruction parity" or "upper parity" and "lower parity").
>
> Tim.
>
> Sent from my PDP-8/E
>  --
> From: Leo Broukhis 
> Sent: ‎2/‎9/‎2015 3:33 PM
> To: simh@trailing-edge.com
> Subject: [Simh] A terminology question
>
>   Dear colleagues,
>
> There is an implementation detail in the BESM-6 architecture the name of
> which we've struggled to translate adequately.  There is a feature
> preventing execution of arbitrary data as instructions implemented using
> two parity bits per word, for the upper and the lower half-word. The
> overall parity must be odd, and one of the valid parity bit configurations
> denotes an instruction, and the other denotes data. In the original
> documentation this mechanism was called
> https://translate.google.com/#ru/en/%D1%81%D0%B2%D0%B5%D1%80%D1%82%D0%BA%D0%B0
> (the two forms were called literally "command convolution" and "number
> convolution").
>
>  Unlike a tagged architecture, there isn't a fixed tag value to indicate
> instructions or data.
>
> Is there a standard term for this? "Convolution" sounds too mathematical.
>
>  Thanks,
> Leo
>
>
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Re: [Simh] A terminology question [off topic]

[lists]

On Wed, 11 Feb 2015 12:35:28 +
"Shoppa, Tim"  wrote:

> Sent from my PDP-8/E

Seriously? That would be mighty impressive!

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Re: [Simh] A terminology question

[Shoppa, Tim]

Rather than "convolution", maybe "parity", "check", "hash", or "fingerprint"? 
Like "command parity" and"number parity" plus two "invalid parities"?

Many buses have multiple parity bits already (e.g. "address parity" and 
"instruction parity" or "upper parity" and "lower parity").

Tim.

Sent from my PDP-8/E

From: Leo Broukhis
Sent: ‎2/‎9/‎2015 3:33 PM
To: simh@trailing-edge.com
Subject: [Simh] A terminology question

Dear colleagues,

There is an implementation detail in the BESM-6 architecture the name of which 
we've struggled to translate adequately.  There is a feature preventing 
execution of arbitrary data as instructions implemented using two parity bits 
per word, for the upper and the lower half-word. The overall parity must be 
odd, and one of the valid parity bit configurations denotes an instruction, and 
the other denotes data. In the original documentation this mechanism was called 
https://translate.google.com/#ru/en/%D1%81%D0%B2%D0%B5%D1%80%D1%82%D0%BA%D0%B0 
(the two forms were called literally "command convolution" and "number 
convolution").

Unlike a tagged architecture, there isn't a fixed tag value to indicate 
instructions or data.

Is there a standard term for this? "Convolution" sounds too mathematical.

Thanks,
Leo

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Re: [Simh] A terminology question

[Pontus Pihlgren]

If I understand it correctly, you have four combinations:

11 -- illegal
10 -- data
01 -- instruction
00 -- illegal

And memory locations market illegal or data wont be executed?

This reminds me of the more modern terms "DEP" - Data Execution 
Prevention, "NX" - No-eXecute, "XD" - eXecute Disable, "XN" - eXecute 
Never. DEP and NX seems to be a generic terms and the others are 
platform specific. Different OSs that take advantage of this calls it 
different things.

Not quite the same as the DEP is usually enforced on memory pages.

/P

On Mon, Feb 09, 2015 at 12:32:47PM -0800, Leo Broukhis wrote:
> Dear colleagues,
> 
> There is an implementation detail in the BESM-6 architecture the name of
> which we've struggled to translate adequately.  There is a feature
> preventing execution of arbitrary data as instructions implemented using
> two parity bits per word, for the upper and the lower half-word. The
> overall parity must be odd, and one of the valid parity bit configurations
> denotes an instruction, and the other denotes data. In the original
> documentation this mechanism was called
> https://translate.google.com/#ru/en/%D1%81%D0%B2%D0%B5%D1%80%D1%82%D0%BA%D0%B0
> (the two forms were called literally "command convolution" and "number
> convolution").
> 
> Unlike a tagged architecture, there isn't a fixed tag value to indicate
> instructions or data.
> 
> Is there a standard term for this? "Convolution" sounds too mathematical.
> 
> Thanks,
> Leo

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