x86 architecture concepts - Page 3

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Re: x86 architecture concepts
On 26 Feb 2005 20:54:26 +0100, snipped-for-privacy@rupert.sysgo.com (Robert Kaiser)

Quoted text here. Click to load it

While the RS-232 "standard" may be adequate for the initial purpose of
connecting a serial signal from a computer (DTE) to a modem (DCE) in
an adjacent rack, the worst problems with RS-232 for any general
purpose interface is the far too high impedance levels compared to any
realistic cable characteristic impedance and the problem with ground
potential differences, since no galvanic isolation is required.

Paul
 

Re: x86 architecture concepts
Quoted text here. Click to load it

The PIC does seem like a bit of mess

Quoted text here. Click to load it

When the 8051 was introduced, it was damned elegent.  

Everybody I knew loved it.  

Since then, people have taken it and tried to use it in some
very inappropriate (IMO) situations.  For example, the
architecture simply wasn't intended to deal with more than 64K
of code, with external RAM, or with a stack-intensive language
like C.  Sure there are kludges you can use to do those sorts
of things, but it's not pretty.

When used in the intended ways, the 8051 was (and is) rather
elegent.

Even the most elegent hammer in the world doesn't make a very
good screwdriver.

Quoted text here. Click to load it

Never used either.

Quoted text here. Click to load it

I've no complaints about RS-232.  I've seen it misused and
poorly implimented over the years, but I don't see anything
wrong with the standard.

--
Grant Edwards                   grante             Yow!  You should all JUMP
                                  at               UP AND DOWN for TWO HOURS
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts
Quoted text here. Click to load it
It's been a long time since I last designed with and programmed a PIC
(in Assembly) but I will comment on it all the same. AFAIK the PIC was
derived from an IBM peripheral controller (IIRC PIC stands for
peripheral intelligent controller) and it was meant to provide an
additinal (yet minimal) level of intelligence, flexibility and
compactness where usually plain logic would do fine. I think the problem
with PICs is Microchip simply extended it far beyond the original
architecture could stand and so they ended with a jurry rigged solution.
Just as with 8x51. For that matter the x86 architecture suffers the same
problem in order to support legacy applications.

Just my EU0.02.


Re: x86 architecture concepts


Quoted text here. Click to load it

What do you think the standard says?



Re: x86 architecture concepts

Quoted text here. Click to load it

I think it was actually Peripheral Interface Controller.

Quoted text here. Click to load it

I don't think it was IBM, but the rest is mostly right. General
Instrucments adapted the PIC from a Signetics design back in
the 70's to handle I/O related tasks for some other long since
extinct processor.  I think originally it came from Harvard or
somewhere.

Quoted text here. Click to load it

Well put.  The PIC, the 8051, and the IA32 have all suffered
from the universal hammer syndrome.

--
Grant Edwards                   grante             Yow!  Yow! Those people
                                  at               look exactly like Donnie
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts

Quoted text here. Click to load it

IIRC, Intel's part was called the Programmable Interrupt Controller.
It was basically a dedicated function 8 bit controller. My 8085 books
are all in storage or I would look it up.

Bob McConnell
N2SPP


Re: x86 architecture concepts

Quoted text here. Click to load it

While RMX-80 and later on RMX-86 definitely were multitasking
operating systems, did the RMX-86 originally really have multi-user
and network capability ? When did they invent the iRMX name ?

If IBM had selected the multitasking RMX-86, would there have been
enough professionals, who would have understood anything about  real
time and multitasking ? In those days, could you really get any kind
of formal training for such environments ? While working with RSX-11
since the mid 1970's, much in-house training was required even in the
mid-1980's to get most programmers in a team to become familiar with
multitasking issues.

Realistically, if IBM had chosen RMX-86, how many competent
programmers would have been available ? Trying to get the universities
to teach multitasking issues would be very hard, since most of the
professors would have been from the batch (punched card) era :-).

Paul
    

Re: x86 architecture concepts

Quoted text here. Click to load it

Originally?  Now that's digging - I am pretty sure those docs
got tossed a long time ago.  I know Motorola's RMS-68K was
multi-user in '81, so chances are iRMX-86 was also.  
My memory of the ISIS-III -> iNDX and iNDX + iRMX-80 -> iRMX-86
(or was it the other way round) progression is pretty hazy.

iRMX-86 has a history of being used in industrial PC-DOS machines,
where it runs Windows 3.1 through Windows NT as a task/user.  It is
still being designed into systems.

Quoted text here. Click to load it

You don't need to know real-time.  The interface can look just like DOS.
Instead of 'stay resident' one would spawn a separate, killable,
task.  iNDX would have been a better variant, and I confess to
lumping the two together in my head as "that Intel thing in the 80's."

In the ultimate analysis _all_ operating systems are real-time,
just with varying degrees of 'softness' (that's a measure of how
seriously the OS treats getting something done on schedule --
for the non-RTOS'ers.)

Quoted text here. Click to load it

Way more than you can get now.  Motorola and Intel both provided
series of courses on OS, hardware, languages and development systems.
I only attended the 68K one.  The course was pretty good: it convinced
us to drop Motorola and switch to Intel right-quick.  Every
task in 68K needed it's own copy of the run-time library, some 40K -
and 10 tasks x 40K was a _lot_ of EPROMs in '81.

Quoted text here. Click to load it

Oh, I remember that.  I did some traveling tent shows getting
clients to use an RTOS.  It was like convincing a C programmer to
use Pascal.  Engineers are stubborn beasts.  Though once you can
get them to switch they latch on to the new method as tightly as
they latched on to the old.  Engineers are 'show me' types.

Quoted text here. Click to load it

'Competent' - probably more as the PC would have an instant
entry into factory automation.  

Now incompetent we had in spades what with Basic coming
for free with the machine.  Competent ones took a look at
Lifeboat C, the Phoenix linker, MS compilers and ran for
the hills.  Remember Debug and Edlin.

Quoted text here. Click to load it

In my experience profs stayed pretty much at the leading edge,
often defining it.  It may be different at non-research
colleges.

Industrial consulting makes up a real-big chunk of an Engineering
prof's income - stick in the mud's need not apply.  There was
a lot of research into real-time networks and distributed
processing in the early 70's.  The first 6800's (like the first
dozen) went to Universities.  At Case a grad student promptly
pushed the 40 pin cerdip in the middle to get it into the socket
and it cracked - surpassingly, it still worked.  When was
DARPA net developed?

It is after they graduate and spend some time on their first
job that engineers' minds shut tight to new ideas.  If the
technology in their first job is the same as they were imprinted
with at school then heaven help you.


--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts

Quoted text here. Click to load it

I'm not buying that arguement.  From what I knew, most CP/M
applications were just re-written by hand.  I never met anybody
who had used the mythical 8080 -> 8086 assembly language
translator.  Since there was a CP/M for the 68K, I don't see
how the pseudo-backwards comopatibility with the 8086 made much
difference.

Quoted text here. Click to load it

That's for sure.

--
Grant Edwards                   grante             Yow!  Look DEEP into the
                                  at               OPENINGS!! Do you see any
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts
Quoted text here. Click to load it

One of the largest applications of the time was Wordstar.  All you
have to do is look at the code for it, and you can immediately
detect the application of that conversion tool.  The tool didn't
necessarily leave a complete functional source, because some things
would depend on code size, but it was close.

It was not the existence of CP/M that counted, but the existence of
the applications.  Early MsDos implemented all the system calls of
CP/M, although they fouled up some in typical MsDos fashion.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts

Quoted text here. Click to load it

I've done a bit of '85->'86 translation.  No, I didn't have a
'tool' to do it.  I did 90% of it with Brief key-stroke macros.
The result was like German->English using only a dictionary and
not changing the grammar, but it did work and was a fast, accurate
and easy job -- something that doesn't come along very often.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts

Quoted text here. Click to load it

Did Intel ever actually ship a translator or was that all just
handwaving and hype?

Quoted text here. Click to load it

I'll concede that it would take longer to convert to 68K
assembly.

--
Grant Edwards                   grante             Yow!  Hmmm... A hash-singer
                                  at               and a cross-eyed guy were
We've slightly trimmed the long signature. Click to see the full one.
Re: x86 architecture concepts

Quoted text here. Click to load it

I've just recently finished a project very like this - translating from
COP8 to NEC 78K0 using a pure algorithmic translation method. It worked
amazingly well; I was very surprised.


Re: x86 architecture concepts

[...]
Quoted text here. Click to load it

I'm not sure what "decision" you guys are talking about.  But I don't
agree with "That's for sure" regardless.

Remember that, for all his "reputation" as a techie, Gates is a
_businessman_.  Had things happened differently, he might not have had
such an initial boost, but he would have been working all along to
gain as much market as he could.  When IBM approached Microsoft in the
first place, they were primarily a development tool shop (Microsoft
BASIC).  Gates wants Microsoft to be the company that writes all the
software.  Microsoft sells the most software, not because it's the
best, but because it is the best marketed.  And technical superiority
is no guarantee of market success.  

So if IBM had gone with DR or Intel for the operating system, or with
Moto 68k for the micro and yet someone else for the OS, Microsoft
might not be as big as it is today, but it would certainly be big.
Perhaps even dominant.

Regards,

                               -=Dave
--
Change is inevitable, progress is not.

Re: x86 architecture concepts



Quoted text here. Click to load it

Does anyone watch TV

IBM went to DR first.  They did not agree to IBMs terms
Gate bought DOS 1.0 from some guy who wrote it at home.  He did this so He
could sell BASIC with it.
X86 was chosen for time reasons.



Re: x86 architecture concepts
Quoted text here. Click to load it

The translator did exist.  I had the 2 8"
floppy set.  Nobody used it where I worked.
By the early 80's, we were supporting CP/M,
MS/DOS and CP/M86, all with one C source file
and targeted compiles.  So yeah, you're right.

One could make a somewhat strained argument
that the architectual and market simularities
of the 8080 and the 8086 (and CPM/ - MS/DOS)
made them a good pair for "compatible"
compilers, but that would be something of a
stretch.



Re: x86 architecture concepts

Quoted text here. Click to load it

I agree with you with two arms and two legs up. The compatibility desicion
Intel made was brilliant. Just look at i432, i860 and IA64.  i432 died
before it released. i860 was not successful at all, found its place in
embedded devices, or intel super computers only. IA64 almost killed Intel.
On the other hand, AMD got a new breath after it designed AMD64, the latest
family member of X86.

Think what would have happened if Zilog designed the Z180 other than Z8000
in 1979, or Motorola designed an extension of 6800 otherthan the 68000 in
1979... They would have been able to compete better.

vax, 9000


Re: x86 architecture concepts
Quoted text here. Click to load it

Np. We'd have a different one. The industry needed a monopolist,
and it chose one. Everyone wanted to interchange their files with
everyone else, after all.  I don't think we fared well with our
collective choice, but there was going to be a monopoly one way
or another.

Clifford Heath.

Re: x86 architecture concepts

Quoted text here. Click to load it

Interchange of files is inhibited by the monopoly- it's hard enough to
interchange files with previous versions of Microsoftandbrown, because
of sneaky format changes designed to protect the monopoly. "HTML" that
only works with IE?

A common platform for applications is more the reason - though if p-code
had been fast enough early on, this would not have been much of a
problem, just as Java is popular now.

Paul Burke

Re: x86 architecture concepts

Quoted text here. Click to load it

In the book 'A Random Walk Down Wall Street' the author claims that
statistically there has to be someone with that sort of monopoly/
money - it doesn't matter who or in what business.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
We've slightly trimmed the long signature. Click to see the full one.

Site Timeline