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Re: Where do byte orders come from

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  Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-24 03:51 -0700
    Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-24 03:54 -0700
      Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-24 04:00 -0700
      Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-24 15:54 +0000
        Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-24 09:23 -0700
        Re: Where do byte orders come from Gareth Evans <headstone255@yahoo.com> - 2020-07-24 17:28 +0100
          Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-24 09:56 -0700
            Re: Where do byte orders come from Radey Shouman <shouman@comcast.net> - 2020-07-24 14:08 -0400
              Re: Where do byte orders come from robin.vowels@gmail.com - 2020-07-24 17:54 -0700
              Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-25 01:57 -0700
                Re: Where do byte orders come from Gareth Evans <headstone255@yahoo.com> - 2020-07-25 11:57 +0100
                  Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-25 17:23 +0000
                  Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-25 11:39 -0700
                    Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-25 14:43 -0700
                      Re: Where do byte orders come from Bob Eager <news0073@eager.cx> - 2020-07-25 22:21 +0000
                        Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-25 22:49 +0000
                      Re: Where does PDP-11 floating point come from John Levine <johnl@taugh.com> - 2020-07-25 22:34 +0000
                Re: Where do byte orders come from Radey Shouman <shouman@comcast.net> - 2020-07-25 14:38 -0400
                  Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-25 11:42 -0700
                    Re: Where do byte orders come from Radey Shouman <shouman@comcast.net> - 2020-07-26 17:11 -0400
                    Re: Where do byte orders come from Radey Shouman <shouman@comcast.net> - 2020-07-26 17:13 -0400
                    Re: Where do byte orders come from Radey Shouman <shouman@comcast.net> - 2020-07-26 17:15 -0400
                      Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-26 16:22 -0700
                        Re: Where do byte orders come from Ahem A Rivet's Shot <steveo@eircom.net> - 2020-07-27 06:35 +0100
                          Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-27 11:42 -0700
                            Re: Where do byte orders come from JimP <solosam90@gmail.com> - 2020-07-27 13:54 -0500
                        Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-27 00:37 -0700
                          Re: Where do byte orders come from Ahem A Rivet's Shot <steveo@eircom.net> - 2020-07-27 09:05 +0100
                            Re: Where do byte orders come from "Kerr-Mudd,John" <notsaying@127.0.0.1> - 2020-07-27 11:27 +0000
                            Re: Where do byte orders come from JimP <solosam90@gmail.com> - 2020-07-27 10:27 -0500
                              Re: Where do byte orders come from Rich Alderson <news@alderson.users.panix.com> - 2020-07-27 20:45 -0400
                                Re: Where do byte orders come from JimP <solosam90@gmail.com> - 2020-07-28 09:24 -0500
                                  Re: Where do byte orders come from Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2020-07-28 17:30 +0000
                                    Re: Where do byte orders come from JimP <chucktheouch@gmail.com> - 2020-07-28 15:56 -0500
                            Re: Where do byte orders come from Andy Walker <anw@cuboid.co.uk> - 2020-07-27 22:34 +0100
                        Re: Where do byte orders come from Andreas Eder <a_eder_muc@web.de> - 2020-08-02 12:00 +0200
                          Re: Where do byte orders come from JimP <chucktheouch@gmail.com> - 2020-08-02 14:02 -0500
                            Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-08-02 15:03 -0700
                              Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-08-02 22:59 +0000
                              Re: Where do byte orders come from Thomas Koenig <tkoenig@netcologne.de> - 2020-08-03 06:57 +0000
                              Re: Where do byte orders come from maus <maus@dmaus.org> - 2020-08-08 22:21 +0000
                                Re: Where do byte orders come from Rich Alderson <news@alderson.users.panix.com> - 2020-08-09 16:50 -0400
                                  Re: Where do byte orders come from maus <maus@dmaus.org> - 2020-08-10 23:07 +0000
                                    Re: Where do byte orders come from J. Clarke <jclarke.873638@gmail.com> - 2020-08-10 19:14 -0400
                                      Re: How did byte order get to horses? Dan Espen <dan1espen@gmail.com> - 2020-08-10 20:39 -0400
                                        Re: How did byte order get to horses? J. Clarke <jclarke.873638@gmail.com> - 2020-08-10 20:51 -0400
                                          Re: How did byte order get to horses? Dan Espen <dan1espen@gmail.com> - 2020-08-10 22:38 -0400
                                            Re: How did byte order get to horses? J. Clarke <jclarke.873638@gmail.com> - 2020-08-10 22:50 -0400
                                              Re: How did byte order get to horses? robin.vowels@gmail.com - 2020-08-10 20:35 -0700
                                    Re: Where do byte orders come from Mike Spencer <mds@bogus.nodomain.nowhere> - 2020-08-11 03:42 -0300
                            Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-08-03 07:45 -0700
                              Re: Where do byte orders come from JimP <chucktheouch@gmail.com> - 2020-08-03 13:45 -0500
                                Re: Where do byte orders come from Rich Alderson <news@alderson.users.panix.com> - 2020-08-06 23:47 -0400
                          Re: Where do byte orders come from Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2020-08-02 21:58 +0000
                          Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-08-02 15:04 -0700
                  Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-25 14:43 -0700
                    Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-25 22:35 +0000
                    Re: Where do byte orders come from Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2020-07-25 16:54 -0600
                    Re: Where do byte orders come from Gareth Evans <headstone255@yahoo.com> - 2020-07-26 09:43 +0100
                      Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-26 05:54 -0700
            Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-25 02:03 -0700
              Re: Where do byte orders come from Ahem A Rivet's Shot <steveo@eircom.net> - 2020-07-25 10:54 +0100
                Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-25 17:25 +0000
          Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-24 10:32 -0700
            Re: Where do byte orders come from Peter Flass <peter_flass@yahoo.com> - 2020-07-24 11:45 -0700
              Re: Where do byte orders come from scott@slp53.sl.home (Scott Lurndal) - 2020-07-24 19:32 +0000
                Re: Where do byte orders come from Richard Milward <rsmilward@gmail.com> - 2020-10-07 12:45 -0700
            Re: Where do byte orders come from Ahem A Rivet's Shot <steveo@eircom.net> - 2020-07-24 20:54 +0100
              Re: Where do byte orders come from Quadibloc <jsavard@ecn.ab.ca> - 2020-07-25 01:55 -0700
            Re: Where do byte orders come from Dan Espen <dan1espen@gmail.com> - 2020-07-24 16:40 -0400
          Re: Where do byte orders come from John Levine <johnl@taugh.com> - 2020-07-24 19:30 +0000
        Re: Where do byte orders come from Ahem A Rivet's Shot <steveo@eircom.net> - 2020-07-24 21:06 +0100

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#212305 — Re: Where do byte orders come from

On Saturday, August 10, 2019 at 1:04:57 PM UTC-6, googlegroups jmfbahciv wrote:

> Who did the design?  If it was someone who left to start up Data General,
> perhaps reading _The Soul of a Machine_ might give hints.

The guy who left to start up Data General, Edson de Castro, designed the PDP-5 
architecture which was later used in the PDP-8. He left specifically because they 
rejected his design for their 16-bit computer, and made the PDP-11 instead.

John Savard

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#212306

On Friday, July 24, 2020 at 4:51:27 AM UTC-6, Quadibloc wrote:
> On Saturday, August 10, 2019 at 1:04:57 PM UTC-6, googlegroups jmfbahciv wrote:
> 
> > Who did the design?  If it was someone who left to start up Data General,
> > perhaps reading _The Soul of a Machine_ might give hints.
> 
> The guy who left to start up Data General, Edson de Castro, designed the PDP-5 
> architecture which was later used in the PDP-8. He left specifically because they 
> rejected his design for their 16-bit computer, and made the PDP-11 instead.

While this page doesn't explain when the decision to include little-endian was 
made, it does name the originator of the design for the PDP-11: Harold 
McFarland.

https://history-computer.com/ModernComputer/Electronic/PDP-11.html

John Savard

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#212308

On Friday, July 24, 2020 at 4:54:17 AM UTC-6, Quadibloc wrote:
> On Friday, July 24, 2020 at 4:51:27 AM UTC-6, Quadibloc wrote:
> > On Saturday, August 10, 2019 at 1:04:57 PM UTC-6, googlegroups jmfbahciv wrote:
> > 
> > > Who did the design?  If it was someone who left to start up Data General,
> > > perhaps reading _The Soul of a Machine_ might give hints.
> > 
> > The guy who left to start up Data General, Edson de Castro, designed the PDP-5 
> > architecture which was later used in the PDP-8. He left specifically because they 
> > rejected his design for their 16-bit computer, and made the PDP-11 instead.
> 
> While this page doesn't explain when the decision to include little-endian was 
> made, it does name the originator of the design for the PDP-11: Harold 
> McFarland.
> 
> https://history-computer.com/ModernComputer/Electronic/PDP-11.html

And this page

http://hampage.hu/pdp-11/birth.html

has some more information.

John Savard

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#212310

In article <0972e4a9-2307-449f-8d23-9ff404af98b3o@googlegroups.com>,
Quadibloc  <jsavard@ecn.ab.ca> wrote:
>While this page doesn't explain when the decision to include little-endian was 
>made, it does name the originator of the design for the PDP-11: Harold 
>McFarland.
>
>https://history-computer.com/ModernComputer/Electronic/PDP-11.html

I have been trying for many years to find out why DEC used a
little-endian byte order in the PDP-11 rather than the big-endian that
all then-existing byte addressable machine used.

So far nobody has 'fessed up, although lots of people have sent along
uninformed speculation. I know lots of reasons that DEC might have
chosen little-endian, but I don't know why they actually did.



-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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#212311

On Friday, July 24, 2020 at 9:54:58 AM UTC-6, John Levine wrote:
> In article <0972e4a9-2307-449f-8d23-9ff404af98b3o@googlegroups.com>,
> Quadibloc  <jsavard@ecn.ab.ca> wrote:
> >While this page doesn't explain when the decision to include little-endian was 
> >made, it does name the originator of the design for the PDP-11: Harold 
> >McFarland.
> >
> >https://history-computer.com/ModernComputer/Electronic/PDP-11.html
> 
> I have been trying for many years to find out why DEC used a
> little-endian byte order in the PDP-11 rather than the big-endian that
> all then-existing byte addressable machine used.

> So far nobody has 'fessed up, although lots of people have sent along
> uninformed speculation. I know lots of reasons that DEC might have
> chosen little-endian, but I don't know why they actually did.

Incidentally, from some other sources, I see that MacFarland brought over the 
"nucleus" of the PDP-11 design. In "What Have We Learned from the PDP-11", 
Gordon Bell notes that giving it byte addressing was one of the significant ways 
in which it was an improvement on previous architectures.

In the absence of a more detailed account of the development of the PDP-11, I'm 
afraid that "speculation" is all we have.

John Savard

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#212312

On 24/07/2020 16:54, John Levine wrote:
> In article <0972e4a9-2307-449f-8d23-9ff404af98b3o@googlegroups.com>,
> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>> While this page doesn't explain when the decision to include little-endian was
>> made, it does name the originator of the design for the PDP-11: Harold
>> McFarland.
>>
>> https://history-computer.com/ModernComputer/Electronic/PDP-11.html
> 
> I have been trying for many years to find out why DEC used a
> little-endian byte order in the PDP-11 rather than the big-endian that
> all then-existing byte addressable machine used.
> 
> So far nobody has 'fessed up, although lots of people have sent along
> uninformed speculation. I know lots of reasons that DEC might have
> chosen little-endian, but I don't know why they actually did.
> 
> 
> 

But Little Endian is the obvious and logical approach,
otherwise when dealing with multi precision you have to fart
about to get to the least significant byte when presented
with the address of the variable in memory.

The only justification for Big Endian seems to come from
lazy programmers who need their hands held and nose
wiped when looking at core dumps.

HTH YMMV EOE

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#212314

Gareth Evans <headstone255@yahoo.com> wrote:
> On 24/07/2020 16:54, John Levine wrote:
>> In article <0972e4a9-2307-449f-8d23-9ff404af98b3o@googlegroups.com>,
>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>> While this page doesn't explain when the decision to include little-endian was
>>> made, it does name the originator of the design for the PDP-11: Harold
>>> McFarland.
>>> 
>>> https://history-computer.com/ModernComputer/Electronic/PDP-11.html
>> 
>> I have been trying for many years to find out why DEC used a
>> little-endian byte order in the PDP-11 rather than the big-endian that
>> all then-existing byte addressable machine used.
>> 
>> So far nobody has 'fessed up, although lots of people have sent along
>> uninformed speculation. I know lots of reasons that DEC might have
>> chosen little-endian, but I don't know why they actually did.
>> 
>> 
>> 
> 
> But Little Endian is the obvious and logical approach,
> otherwise when dealing with multi precision you have to fart
> about to get to the least significant byte when presented
> with the address of the variable in memory.
> 
> The only justification for Big Endian seems to come from
> lazy programmers who need their hands held and nose
> wiped when looking at core dumps.
> 

No, big-endian is the logical approach for any machine bigger that an 8008,
since words are operated on, and brought into the ALU, as a unit.
Big-endian is the way people think of numbers, otherwise you’d write
amounts like 00.000,1$ for a thousand dollars.

-- 
Pete

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#212317

Peter Flass <peter_flass@yahoo.com> writes:

> Gareth Evans <headstone255@yahoo.com> wrote:
>> On 24/07/2020 16:54, John Levine wrote:
>>> In article <0972e4a9-2307-449f-8d23-9ff404af98b3o@googlegroups.com>,
>>> Quadibloc  <jsavard@ecn.ab.ca> wrote:
>>>> While this page doesn't explain when the decision to include
>>>> little-endian was
>>>> made, it does name the originator of the design for the PDP-11: Harold
>>>> McFarland.
>>>> 
>>>> https://history-computer.com/ModernComputer/Electronic/PDP-11.html
>>> 
>>> I have been trying for many years to find out why DEC used a
>>> little-endian byte order in the PDP-11 rather than the big-endian that
>>> all then-existing byte addressable machine used.
>>> 
>>> So far nobody has 'fessed up, although lots of people have sent along
>>> uninformed speculation. I know lots of reasons that DEC might have
>>> chosen little-endian, but I don't know why they actually did.
>>> 
>>> 
>>> 
>> 
>> But Little Endian is the obvious and logical approach,
>> otherwise when dealing with multi precision you have to fart
>> about to get to the least significant byte when presented
>> with the address of the variable in memory.
>> 
>> The only justification for Big Endian seems to come from
>> lazy programmers who need their hands held and nose
>> wiped when looking at core dumps.
>> 
>
> No, big-endian is the logical approach for any machine bigger that an 8008,
> since words are operated on, and brought into the ALU, as a unit.
> Big-endian is the way people think of numbers, otherwise you’d write
> amounts like 00.000,1$ for a thousand dollars.

When writing Arabic* that's exactly how it's done.  That is, the digit
order is the same as it is in Latin script, which is opposite the letter
order for words.  Although "arabic numerals" is perhaps a misattribution
it does seem that that is whence they were adopted by Europeans.  It
seems they just got the endianness wrong -- to be consistent they should
have reversed the order.

Least significant digit first is also exactly how numbers are written
when they are being calculated by hand, which was the point of
zero-based notation in the first place.

* I would guess this is true of other languages using Arabic script,
  like Farsi and Urdu.  No idea about Hebrew.

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#212329

On Saturday, July 25, 2020 at 4:08:27 AM UTC+10, Radey Shouman wrote:
> Peter Flass <p......@yahoo.com> writes:
> 
> > Gareth Evans <h......@yahoo.com> wrote:
> >> On 24/07/2020 16:54, John Levine wrote:
> >>> In article <0972e4a9-2307-449f-8d23-......@googlegroups.com>,
> >>> Quadibloc  <j......@ecn.ab.ca> wrote:
> >>>> While this page doesn't explain when the decision to include
> >>>> little-endian was
> >>>> made, it does name the originator of the design for the PDP-11: Harold
> >>>> McFarland.
> >>>> 
> >>>> https://history-computer.com/ModernComputer/Electronic/PDP-11.html
> >>> 
> >>> I have been trying for many years to find out why DEC used a
> >>> little-endian byte order in the PDP-11 rather than the big-endian that
> >>> all then-existing byte addressable machine used.
> >>> 
> >>> So far nobody has 'fessed up, although lots of people have sent along
> >>> uninformed speculation. I know lots of reasons that DEC might have
> >>> chosen little-endian, but I don't know why they actually did.
> >>> 
> >>> 
> >>> 
> >> 
> >> But Little Endian is the obvious and logical approach,
> >> otherwise when dealing with multi precision you have to fart
> >> about to get to the least significant byte when presented
> >> with the address of the variable in memory.

> > No, big-endian is the logical approach for any machine bigger that an 8008,
> > since words are operated on, and brought into the ALU, as a unit.
> > Big-endian is the way people think of numbers, otherwise you’d write
> > amounts like 00.000,1$ for a thousand dollars.
> 
> When writing Arabic* that's exactly how it's done.  That is, the digit
> order is the same as it is in Latin script, which is opposite the letter
> order for words.  Although "arabic numerals" is perhaps a misattribution
> it does seem that that is whence they were adopted by Europeans.  It
> seems they just got the endianness wrong -- to be consistent they should
> have reversed the order.
> 
> Least significant digit first is also exactly how numbers are written
> when they are being calculated by hand, which was the point of
> zero-based notation in the first place.

ACE and DEUCE held values internally in "Chinese" binary, that it with the
least-significant bit on the left.

Being serial machines, the least-significant bit of a word
emerged first from storage on its way to the adders.

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#212337

On Friday, July 24, 2020 at 12:08:27 PM UTC-6, Radey Shouman wrote:
> Peter Flass <peter_flass@yahoo.com> writes:

> > Big-endian is the way people think of numbers, otherwise you’d write
> > amounts like 00.000,1$ for a thousand dollars.

> When writing Arabic* that's exactly how it's done.  That is, the digit
> order is the same as it is in Latin script, which is opposite the letter
> order for words.  Although "arabic numerals" is perhaps a misattribution
> it does seem that that is whence they were adopted by Europeans.  It
> seems they just got the endianness wrong -- to be consistent they should
> have reversed the order.

Ah, but the languages of India are written from left to right, like ours. So the 
Arabs got the order wrong, and Europeans corrected it!

But you _are_ right that it is going too far to say that big-endian is "the way 
humans think of numbers".

John Savard

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#212344

On 25/07/2020 09:57, Quadibloc wrote:
> On Friday, July 24, 2020 at 12:08:27 PM UTC-6, Radey Shouman wrote:
>> Peter Flass <peter_flass@yahoo.com> writes:
> 
>>> Big-endian is the way people think of numbers, otherwise you’d write
>>> amounts like 00.000,1$ for a thousand dollars.
> 
>> When writing Arabic* that's exactly how it's done.  That is, the digit
>> order is the same as it is in Latin script, which is opposite the letter
>> order for words.  Although "arabic numerals" is perhaps a misattribution
>> it does seem that that is whence they were adopted by Europeans.  It
>> seems they just got the endianness wrong -- to be consistent they should
>> have reversed the order.
> 
> Ah, but the languages of India are written from left to right, like ours. So the
> Arabs got the order wrong, and Europeans corrected it!
> 
> But you _are_ right that it is going too far to say that big-endian is "the way
> humans think of numbers".

The writing of numbers by humans has nothing whatsoever to do
with the internal operation of computers.

But am I right in remembering that the PDP11 had a mix of Big
and Little Endian; the basic processor being Little but some of
the floating point options being Big?

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#212347

In article <rfh36i$jsc$2@dont-email.me>,
Gareth Evans  <headstone255@yahoo.com> wrote:
>But am I right in remembering that the PDP11 had a mix of Big
>and Little Endian; the basic processor being Little but some of
>the floating point options being Big?

Yes, some of the multi-word arithmetic formats were middle-endian.

They straigtened it all out on the VAX, but the fact that it was
so hard to make things consistently little-endian tells us that
the arguement that it's more "natural" is silly.



-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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#212353

On Saturday, July 25, 2020 at 4:57:23 AM UTC-6, Gareth Evans wrote:
> On 25/07/2020 09:57, Quadibloc wrote:

> > But you _are_ right that it is going too far to say that big-endian is "the way
> > humans think of numbers".

> The writing of numbers by humans has nothing whatsoever to do
> with the internal operation of computers.

Computers operate on character strings internally, and those character strings 
get sent to printers to produce text for humans to read.

> But am I right in remembering that the PDP11 had a mix of Big
> and Little Endian; the basic processor being Little but some of
> the floating point options being Big?

Yes. I think it was big-endian due to a lack of communication... as the PDP-11 
was the first attempt to make a computer consistently little-endian, this was a 
novel and unfamiliar concept, and so if the team making the floating-point add-
on didn't have that concept clearly and firmly explained to them, naturally they 
would just make the floating-point processor in the way they would assume to be 
right and natural and the same as every other computer used.

John Savard

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#212361

Quadibloc <jsavard@ecn.ab.ca> wrote:
> On Saturday, July 25, 2020 at 4:57:23 AM UTC-6, Gareth Evans wrote:
>> On 25/07/2020 09:57, Quadibloc wrote:
> 
>>> But you _are_ right that it is going too far to say that big-endian is "the way
>>> humans think of numbers".
> 
>> The writing of numbers by humans has nothing whatsoever to do
>> with the internal operation of computers.
> 
> Computers operate on character strings internally, and those character strings 
> get sent to printers to produce text for humans to read.
> 
>> But am I right in remembering that the PDP11 had a mix of Big
>> and Little Endian; the basic processor being Little but some of
>> the floating point options being Big?
> 
> Yes. I think it was big-endian due to a lack of communication... as the PDP-11 
> was the first attempt to make a computer consistently little-endian, this was a 
> novel and unfamiliar concept, and so if the team making the floating-point add-
> on didn't have that concept clearly and firmly explained to them, naturally they 
> would just make the floating-point processor in the way they would assume to be 
> right and natural and the same as every other computer used.

I thought I read somewhere that FP in the early -11s was originally
software only. (maybe from Bell?)


-- 
Pete

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#212363

On Sat, 25 Jul 2020 14:43:37 -0700, Peter Flass wrote:

> Quadibloc <jsavard@ecn.ab.ca> wrote:
>> On Saturday, July 25, 2020 at 4:57:23 AM UTC-6, Gareth Evans wrote:
>>> On 25/07/2020 09:57, Quadibloc wrote:
>> 
>>>> But you _are_ right that it is going too far to say that big-endian
>>>> is "the way humans think of numbers".
>> 
>>> The writing of numbers by humans has nothing whatsoever to do with the
>>> internal operation of computers.
>> 
>> Computers operate on character strings internally, and those character
>> strings get sent to printers to produce text for humans to read.
>> 
>>> But am I right in remembering that the PDP11 had a mix of Big and
>>> Little Endian; the basic processor being Little but some of the
>>> floating point options being Big?
>> 
>> Yes. I think it was big-endian due to a lack of communication... as the
>> PDP-11 was the first attempt to make a computer consistently
>> little-endian, this was a novel and unfamiliar concept, and so if the
>> team making the floating-point add- on didn't have that concept clearly
>> and firmly explained to them, naturally they would just make the
>> floating-point processor in the way they would assume to be right and
>> natural and the same as every other computer used.
> 
> I thought I read somewhere that FP in the early -11s was originally
> software only. (maybe from Bell?)

Pretty sure our 11/20 didn't have it.

As it happens, I've been doing a disassembler for the PDP-11 over the 
last couple of days. I identified the EIS floating point (four 
instructions, very simple) and the FP-11 floating point (lots of 
instructions, a bit arcane).



-- 
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
 http://www.mirrorservice.org

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#212366

In article <ho3pjiFmsnaU9@mid.individual.net>,
Bob Eager  <news0073@eager.cx> wrote:
>> I thought I read somewhere that FP in the early -11s was originally
>> software only. (maybe from Bell?)
>
>Pretty sure our 11/20 didn't have it.

I happen to have a pdp11/20/15/r20 handbook in my hand and I can
assure you there was no floating point available, only an optional
extended arithmetic peripheral that did what EIS later did, in a
different way.



-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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#212364 — Re: Where does PDP-11 floating point come from

In article <117289487.617406095.513470.peter_flass-yahoo.com@news.eternal-september.org> you write:
>I thought I read somewhere that FP in the early -11s was originally
>software only. (maybe from Bell?)

The FP hardware was always optional although on the larger machines
I think everyone got it.

On the original 11/20 had an optional Unibus arithemetic device that
did multiply and divide and multiple shift, no hardware FP at all.

On the 11/45 and 11/70 it was an additional full sized board that fit
into a reserved backplane slot. For the later 11/23 it was a couple of
chips that plugged into the CPU board.



-- 
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

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#212352

Quadibloc <jsavard@ecn.ab.ca> writes:

> On Friday, July 24, 2020 at 12:08:27 PM UTC-6, Radey Shouman wrote:
>> Peter Flass <peter_flass@yahoo.com> writes:
>
>> > Big-endian is the way people think of numbers, otherwise you’d write
>> > amounts like 00.000,1$ for a thousand dollars.
>
>> When writing Arabic* that's exactly how it's done.  That is, the digit
>> order is the same as it is in Latin script, which is opposite the letter
>> order for words.  Although "arabic numerals" is perhaps a misattribution
>> it does seem that that is whence they were adopted by Europeans.  It
>> seems they just got the endianness wrong -- to be consistent they should
>> have reversed the order.
>
> Ah, but the languages of India are written from left to right, like ours. So the 
> Arabs got the order wrong, and Europeans corrected it!

That would require knowing how they write their numbers.  I don't, do you?

> But you _are_ right that it is going too far to say that big-endian is "the way 
> humans think of numbers".
>
> John Savard

-- 

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#212354

On Saturday, July 25, 2020 at 12:38:17 PM UTC-6, Radey Shouman wrote:
 
> That would require knowing how they write their numbers.  I don't, do you?

As a matter of fact, as a coin collector, yes, I know that old coins from India, 
Thailand, Burma and so on that have dates written using their versions of the 
digits from India have the most significant digit on the left.

John Savard

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#212384

Quadibloc <jsavard@ecn.ab.ca> writes:

> On Saturday, July 25, 2020 at 12:38:17 PM UTC-6, Radey Shouman wrote:
>  
>> That would require knowing how they write their numbers.  I don't, do you?
>
> As a matter of fact, as a coin collector, yes, I know that old coins from India, 
> Thailand, Burma and so on that have dates written using their versions of the 
> digits from India have the most significant digit on the left.

Thanks, that's interesting.

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