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I've written code that runs bare metal under Windows. You just don't ask permission for things, you capture interrupts you need and keep Windows out of your hair.

I see that it runs on MS-DOS. ? At first this might seem primitive. ? But if you have ever written any DOS software what's going on is your software runs on "bare metal". ? To use more modern terms, MS-DOS simply loads the software then runs it allowing complete root level access to the entire PC. ? There is not scheduler and OS to deal with. ??

To say this again on LinuxCNC terms, every MS-DOS program is in effect a real-time HAL module. ? ?

Yes it is primitive as it uses a full up Intel X86 as it it where a micro controller with no OS. ? But that might not be a bad thing for this application.

-- 
Jerry Durand, Durand Interstellar, Inc.

tel: +1 408 356-3886
@DurandInterstel

Jerry,

A quick search for Windows interrupts revealed a substantial number of them.? How is is possible to determine which of them you need to reserve for your own purposes?? It looks to me like it would be awfully easy to get Windows to just seize up, particularly if you are re-allocating resources to homebrew code that does not handle errors well.? Good error handling, in my experience, is the very devil to do well.

Mark

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Ok Ellis, I speak American, not English 8-) and it still makes little sense in the machinist's world....

At the risk of getting stomped all into the dirt, I'm going to attempt an 'Engl-erican' translation that, hopefully, will extract the salient points, and allow the author to straighten it out if I blow it....? I think Chris authored it...? Beat me up if I mess this up Chris... (on or offline)

In the US, those applications that run on MS-DOS are considered a bit barbaric and lacking in sophistication.? The one thing that Chris and I do differ on is that MS-DOS is pretty much the original operating system for the Intel X series up through early Pentiums.? Windows is only an operating system in that it has a kernel that provides the operating system basic instruction set to the hardware (ironically, based on the original MS-DOS calls) with what use to be a GUI application (early Windows) now permanently attached to that kernel.

For those who are still awake, hang in there - here it comes......What this means to us in the machinist community, there are all kinds of schedulers and other Windows related tasks, securities, and other decisions that Windows is making at our expense in time, computer complexity, required memory and just plain distractions for the little brain that is inside the chip.

Linux still permits the separation of those overhead components as does original DOS applications (Microsoft or otherwise).? It wont do fancy things like threading a bolt while receiving email because you are watching YouTube on your wireless network, but if left to it's own devises and without the other distractions, it will run those threads on that bolt faster, better, and with less computer overhead (processor power, memory, disk space, and on and on).

This "bare-iron" approach would actually be the functional block equivalent of a dedicated microprocessor doing nothing but running the machine, but with a more complex operating system and a few basic things like one could run a mill and a lathe from the same computer, but would not be able to without a program reload on a dedicated micro-controller system.

This is the principle called 'Domestic Survival Rule 1' if your mate is doing what you want them to, do not distract them.....? If you want an error free job on that thread, Dont suggest they go watch television at the same time.

This 'keep it simple' principle will make a huge difference if you move from a complex platform down to 'bare iron.'? Once done, it is very hard to go back.

Warren L

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If you were starting now, USB interface! Maybe Bluetooth or WiFi but they're mostly more trouble than needed. I have USB running one mill with Mach3 and I have a USBCNC board for the other mill.

Toss the idea of flipping bits on a parallel port into the same dumpster that all the computers with parallel ports are in.??? I know, you can buy a used old machine on eBay.??? Do you REALLY want to tell your customers that your snazzy CNC device won't work with a single modern computer?

???

???

I have forgotten much, if not almost all, of my hardware design and software programming. If I were to ever attempt to CNC any machine I would have to bring myself back up to date on this, which would mean starting all over again.

-- 
Jerry Durand, Durand Interstellar, Inc.

tel: +1 408 356-3886
@DurandInterstel

--

I really hate going this far off topic (yea - I know "Don't")

MSDOS is an OS. Not really bare metal programming:







Note:
"Bare machine (or bare metal), in computer parlance, means a computer executing instructions directly on logic hardware without an intervening operating system. "

and where it states:
"Bare machine programming remains in common practice in embedded systems <>, where microcontrollers <> or microprocessors <> often boot directly into monolithic, single-purpose software, without loading a separate operating system. Such embedded software <> can vary in structure, but the simplest form may consist of an infinite main loop <>, calling subroutines responsible for checking for inputs, performing actions, and writing outputs."

Bare metal means you really have no OS at all, you do all memory management, I/O interface and any thread management yourself.

MSDOS provides hooks to the hardware to allow for these tasks - so DOS programs really aren't running "bare metal" If you recall MSDOS had memory managers , like EMM386 that allowed access to memory beyond 640K.

For example

Just do a dir /s on the root of a fresh install of MSDOS or FreeDOS and you'll see all the drivers and files that are booted by the OS...

In fact the key part of the MSDOS acronym is the DOS part - Disk Operating System
On a true bare metal system, you'd being doing your disk reads and writes at low level in your code - not just calling the OS to handle it.


For the rest of this rant, a note to those that speak "English":

When I mention non-volatile, equate that to your PC's hard drive. Stuff that has to survive a power down.
When I mention volatile, equate that to your PC's memory sticks. A place for temporary storage.


Typically bare metal programming is usually limited to microcontrollers (see below).

In my day job I develop hardware with things like ARM M and A series cores -some are standalone (NXP/Qualcomm, Microchip/Atmel, ST Micro, etc...). Some are combined on "System on a Chip" architectures where they're combined with additional logic (in some case reconfigurable logic such as in a Field Programmable Gate Array [FPGA])

The M series is a self contained microcontroller (similar to 8 bit things like old Z80, 8051, old Moto 68xx, AVR) offering 32 bit architectures.

These M series have a small MMU [Memory Management Unit] that deals with the on-board RAM and FLASH, and some offer and extended external bus that's limited ( for instance EBI). The non-volatile code for things like the program is stored in Flash, the SRAM (Static RAM) is the working memory where the application stores things like variables.



This memory - both non-volatile and volatile is on the orders of kilobytes to low-megabytes. Yes - kilobytes. Remember those?

For instance -an Arduino has kilobytes of flash and even less ram. It's an 8 bit processor (even the Mega's) and can run at clock speeds of 20MHz or so. Some of the more capable 32 bit ARM M series can run in hundred of Megahertz.


What's on something like a Raspberry PI is known as an A series ARM. This has a more sophisticated MMU for things like gigabytes of external memory (ie - external from the CPU IC) used as working memory . Boot code and/or OS as well as user programs are often in some sort of external non-volatile storage such as an SD Card; some microcontrollers offer booting via USB devices.

ARM A series stuff can run in the Gigahertz speed range. Much more capable. Not as much as a modern Intel or AMD "microprocessor" but still not too shabby. Unless your doing something that require heavy math, graphics, etc...

These usually requires an OS - tho my one coder Sanjay has done some stuff for local aerospace guys that runs "sort of bare metal" - ie no OS. Still heavy reliance on porting of OS drivers for use in single thread bare metal stuff he does...

These A series have an MMU that can run external memory similar to what's in your desktop or laptop (typically DRAM of some type) - in fact they offer little memory on the actual CPU integrated circuit(beyond some small on-chip memory registers and basic initialization/boot code) .

Also note that DRAM is a bit more complex to deal with than SRAM.

Not enough to really run any kind of program - typically require and OS of some sort to manage the larger off-chip DRAM memory.

So...

ARM A series (like in your smart phone or on a Raspberry PI ) usually run an OS. Much more memory (both non-volatile and volatile/working). Higher clock speeds. Support for some higher level graphics and peripherals, with higher speeds. Usually not considered "bare metal" programming,

Phones run an OS like Android or Apple. The Rasp PI runs a version of Linux...

ARM M series run things like your washing machine. Small amounts of memory and slower clock speeds. Slower peripheral speeds.

Typically don't run an OS - tho recently things like FreeRTOS and some embedded linux will run on M style non-MMU devices. FreeRTOS is also an operating system that contains realtime extensions. Usually programmed "bare metal" tho, most microcontrollers have some sort of Integrated Development Environment (IDE) that provides a framework of code - ie, usually the mfg of the IC or architecture will provide "driver" level libraries that hook to things like on-board peripherals and chip features such as DMA.

And a lot of these are flakey as poo... In fact, as I write this one of my coders is battling stoopid in FreeRTOS with regard to vendor supplied framework code for an on-board peripheral


To get on machining topics and as an example - a Cortex M3 series TI LM3S6918 part is what's in the Smoothstepper ESS.


"The ESS also has a microcontroller, which is used for additional processing that the USS would be unable to do."
It's possible that Warp9 is running an OS. These TI parts are what he uses for the actual Ethernet connection - these parts offer both the MAC and the PHY on chip.

For that he's probably using a network stack called LightWeight IP.

So even this isn't really "bare metal" - he's leveraging opensource software for the network functions. Believe me, trying to write your own TCP/IP stack would not be easy...

So now you have a similar situation as what you face with an OS - code that sits between you and your program. Again not totally "bare metal" - you're relying on someone lses code.


So it gets even more arcane - bit more on the Microcontroller vs Microprocessor:



-



The difference between a microcontroller and a microprocessor is getting blurred all the time.

ARM's - both A and M series - are usually considered microcontrollers, tho some of the newer ARM architectures like those from Allwinner and found in things like Personal Electronic Devices (PEDs - can anyone tell I've had to endure security training?) can almost be considered microprocessors.

But this is getting even fuzzier with companies that manufacture A series devices (ones without on-board memory and a more sophisticated MMU as per a microcontroller) offering things like DDRx (1,2,3,4) on a single substrate or multichip module - mimicking a lot of what delineates a "microcontroller".

Typically a microcontroller boots from some sort of on-board, non-volatile memory and has on-board SRAM for things like variable storage and working memory

Typically a microprocessor has some sort of "system bus" that interfaces the CPU to external memory. It has some sort of BIOS firmware to get everything in order on a pwoer up, and boots up from some sort of external non-volatile storage. It usually runs DRAM for working memory


Note that in recent microprocessors more of what used to be supported via a "chipset" is now being put on-board (whether is be on-die or on a multichip module)

As has been typical in the past, a microprocessor usually only offers the CPU and has a system bus that handles things like memory; additional IC's are sometimes used called and MCH (Memory Controller Hub - North Bridge) and an ICH (I/O Controller HUB - South Bridge)

(computing)


Around 2008, Intel incorporated these function into a PCH (Platform Controller Hub)


To extend performance even further, newer things like the latest Intel microprocessors incorporate the PCH features into stuff like the sandy bridge:


Regardless, these higher level architectures really require an OS with support for these features. Granted there are some guys in areas the audio world - one being Voxengo - that writes a lot of stuff in x86/x64 assembly. But it's still not "bare metal" per se... they still require the support of an OS.

Trying to do "bare metal" on an x86 or x64 architecture is do-able, but writing all the support for something like even an older x86 would be a daunting task.



.

I worked for many years with a determinant “soft PLC” program for MS-DOS. (Universal Automation Inc’s “FLOPRO”.) It actually allowed running a second application program for a user interface. But it did it by basically taking over MS-DOS and using “time slicing”. At regular intervals, it would take over the processor, save all registers, do it’s logic scan, and then restore everything and turn it back over to the application program. It worked well, but it got messed up if anything occurred which would trigger the “beep” function. That messed up time in some way they couldn’t get around. So this was like doing a TSR on steroids. Even in MS-DOS, it wasn’t an easy thing to do. In Windows, it is horrifically difficult. Wind River is a company well known for Windows real-time applications. Another is Beckhoff who is very good at the game. (I have used their products for very automated machinery used for semiconductor manufacturing.)

Beckhoff is a “Microsoft Windows Embedded Gold Partner”. One advantage of this is that “Microsoft Certified Partners” get the inside track on “surprises” that Microsoft seems to keep springing on any firm trying to work within its operating systems. Microsoft let’s them see the man behind the curtain. If you aren’t at that sort of design level, you are probably going to have problems trying to get under the hood well enough with any Windows products.

Chuck K.

Sent from Mail for Windows 10

From: 'Michael Jablonski' michaeljab@... [7x12minilathe]
Sent: Friday, July 28, 2017 4:02 PM
To: 7x12minilathe@...
Subject: RE: [7x12minilathe] CNCZEUS is now Open source

?
I know we are running a bit off topic with this thread, but I'll throw in my two cents.
?
MS-DOS was very good and relatively easy?for controlling anything and everything because it allowed you take control of everything. Most of the time only one application was running at a time so you could take control of the hardware and software interrupts without much problems. The problems came when TSR (Terminate and Stay Resident) started making the scene.? We all remember Borland's Sidekick. These were programs that you'd load and they would run in the background, then you could pop them up at any time with the use of HotKeys. They had a bad habit of taking control of so many interrupts they interfered with the main program trying to run.
?
I have forgotten much, if not almost all, of my hardware design and software programming. If I were to ever attempt to CNC any machine I would have to bring myself back up to date on this, which would mean starting all over again.

Michael - California, USA
Micro-Mark MicroLux 7x16
LMS 3990 Hi-Torque Mill with power feed

?

From: 7x12minilathe@... [mailto:7x12minilathe@...]
Sent: Friday, July 28, 2017 11:34 AM
To: 7x12minilathe@...
Subject: Re: [7x12minilathe] CNCZEUS is now Open source
?
Yeah, there's definitely a whole 'nother language when programmers start talking to each other. ??

Basically it means that MS-DOS exposes the most low-level hardware functions of the computer to any program that wants to control them. ?Sending pulses to a CNC system requires very fine control of timing of the output ports (by means of "interrupts"). This direct control afforded by DOS is an advantage for CNC. ?But it's also DOS's downfall--it's almost impossible to prevent software from freezing or crashing the whole system if it's badly or m aliciously written. Anyone who was using DOS back at the beginning remembers having to reboot frequently to recover from crashes.

Windows, on the other hand (especially early versions), is software that runs "on top" of DOS--sort of a fly-by-wire system where the software doesn't directly control the hardware, but it talks to another layer of software that talks to the ports. ?Windows is a multitasking system (unlike DOS which is single tasking only), so other programs might be in competition for those same ports. ?It also uses a lot of processing power for ?the Windows graphical interface, keeping track of mouse movements, etc. ?All of this makes timing those pulses to output ports very tricky, especially on slower machines, so Windows CNC programs tended to have problems with skipped steps, delayed pulses, etc. ?

Bottom line, the things that make Windows a more versatile system for most kinds of software make it really bad at CNC control; and the things that make DOS clunky and insecure for other kinds of software makes it not so bad at CNC control.

The later versions of Windows (and faster hardware) have improved things quite a bit. ?Starting with Windows NT and (I think) Windows 8, it was no longer overlaid on DOS. But there are still a few layers of software and drivers between the user interface and the low-level hardware, and it still is a multitasking system. ?It takes some skilled programming to get fast, accurately timed pulses to the output ports.


From: "'Ellis Cory' ellis103@... [7x12minilathe]" <7x12minilathe@...>
To: 7x12minilathe@...
Sent: Friday, July 28, 2017 2:02 PM
Subject: RE: [7x12minilathe] CNCZEUS is now Open source


?
One of the problems may be that a lot of us on here speak English (well I do) and the message below makes no sense ?
Rgds.
???????? Ellis
?
?
?
I see that it runs on MS-DOS. ? At first this might seem primitive. ? But if you have ever written any DOS software what's going on is your software runs on "bare metal". ? To use more modern terms, MS-DOS simply loads the software then runs it allowing complete root level access to the entire PC. ? There is not scheduler and OS to deal with. ??
?
To say this again on LinuxCNC terms, every MS-DOS program is in effect a real-time HAL module. ? ?
?
Yes it is primitive as it uses a full up Intel X86 as it it wh ere a micro controller with no OS. ? But that might not be a bad thing for this application.

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I'm not sure where the below email was, but it is 12 hours later, I just got up, and it arrived here at 4:38 AM.

Yahoo Magic??

Warren L

blow it....? I think Chris authored it...? Beat me up if I mess this up Chris... (on or offline)

In the US, those applications that run on MS-DOS are considered a bit barbaric and lacking in sophistication.? The one thing that Chris and I do differ on is that MS-DOS is pretty much the original

[snipped]

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Wow, thanks Chris and everyone for this great recompilation of things I have learned and thought about over the years.

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???You can buy parallel port PCI (or PCIe) cards for about $10 to $20. Add a printer port to any brand new computer with an open PCI slot in about 10 or 15 minutes cheap.

???Not that I care a whole lot one way or the other, so long as whatever people decide to use works out for them. But I ran into a need for a parallel port some years ago for a local business, and the solution was very simple and cheap as per above. It was for a custom label printer that had a matching label applicator on an assembly line, so the big rolls of labels they printed up daily were automatically applied to their products as they went by. There was a hardware printer port "key" that plugged into the printer port between the port and printer cord, that the application software had to detect or it would not run in full "unlocked" mode.

???The PCI printer port card installation took perhaps 10 minutes. Windows 7 recognized the new printer port with no issues, and the big problem of new computers not having printer ports turned into a big juicy nothing burger, just like that.

???If someone out there runs into old software / hardware that wants an LPT1 printer port, the solution is only $10 to $20 and easy to do. A potentially important little detail for someone to be aware of in case they ever run into this...

??? Cheers
??? John Z.

On 7/28/2017 7:45 PM, Jerry Durand jerry_durand_california@... [7x12minilathe] wrote: