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CommanderX16 and "What is my dream computer?"

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For amusement or bemusement, I'm comparing 8 Bit Guy's article (http://www.the8bitguy.com/2576/what-is-my-dream-computer/) with the Commander X16.  I expect this to of course be an almost perfect match.  Let's double check!

 

I'll rate each requirement on a "ten-points" scale.

9/10: OFF THE SHELF COMPONENTS

Quote

[...] I prefer to avoid any FPGA or microcontrollers if possible, but that’s not a deal-breaker.

-1 for the FPGA.  (To be fair, though, I suspect this is unavoidable.)

10/10: CPU

The 65C02 at 8mhz ticks all the boxes.

10/10: MEMORY

Quote

I would want 128K or 256 of static RAM, with possibly the ability to upgrade it.  If using 6502 then there will need to be some sort of banking [...]

...exactly what the X16 does.

10/10: VIDEO

Quote

...I’d definitely want the computer to be able to output Composite or VGA...   ...I’d want it to be similar to 8-bit machines of the era, possibly with different modes.  640×480 would be fine for a maximum resolution.... I could see this chip being an FPGA or microcontroller if need be.

Again, VERA ticks the boxes.

 

10/10: SOUND

VERA has the PSG (and PCM) so we're done.  Adding the YM chip is nice for synthesizer fans like 8BG, but frankly that's not the deal-breaker.

 

10/10: STORAGE

He wants an SD card; if necessary, the Commodore IEC serial connection would let him use SD2IEC.  So we get both.  Win-win.

 

10/10: OPERATING SYSTEM

He wants a Commodore "successor" machine, with the Commodore fullscreen editor, that uses PETSCII.

Quote

...Hopefully somebody would even write emulator support for it so that we could code and test on a PC.

...and he got that, too. 

 

 

OVERALL PHILOSOPHY

 

Quote

I want the machine to have some of the conveniences of the modern world, such as SD storage and modern keyboard and video standards.  But, at the same time.. I don’t want it to be “too powerful” because then you begin to lose the magic of an 8-bit system.  

Yup.

 

In short, the X16 is not missing any of the "requirements" of the "dream computer".

Call it 69 out of 70 points.

Edited by rje
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When I compare this with, for instance, Ben Eater's 6502 breadboard, or the FW8B PET single board, or the PE6502, I see this:

10/10 Off the Shelf
10/10 65C02
0/10 128K+ Memory.  These generally live within the 6502's 64K limits, and so don't deal with RAM banking.
10/10 Composite or VGA Video*: Composite for the PET and PE6502, "Poor Man's VGA" for Ben Eater's video card (might need some improvement tho...)
0/10 Sound.  I don't think any of these have sound (does the PET?)

Storage (SD): 2/10 for the PET (IEEE-488), 5/10 for the PE6502 (fast serial), and 0/10 for Ben's breadboard (no I/O).

Commodore Operating System: 10/10 for the PET.  0/10 for the PE6502.  2/10 for Ben's breadboard (because you probably could just drop in a KERNAL).
 

So out of 70 points, 

The standalone PET gets 42 points.
The PE6502 gets 35 points.
Ben's breadboard 6502 gets 32 points.

Edited by rje

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On the other hand, Ben's breadboard projects, being super flexible, have the most potential.  If you can drop in a KERNAL into Ben's project, then it would be in a tie with the standalone PET.  If you could drop in a sound synthesizer, then it would surpass the others.

If you rejiggered the system to use memory banking, you'd then be close to "dream computer" level (there's one schematic posted on Ben's website: https://www.reddit.com/r/beneater/comments/k6tgfg/a_simple_way_to_add_banked_memory_to_be6502/).

You'd need to attach an SD or IEC port.

Of course, all those bits would add up to quite an achievement.

 

Edited by rje

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44 minutes ago, rje said:

 

9/10: OFF THE SHELF COMPONENTS

-1 for the FPGA.  (To be fair, though, I suspect this is unavoidable.)

 

2/10: OFF THE SHELF COMPONENTS

Gray market YM2151/3012 do not meet the criteria.  I am quite certain others will disagree with this opinion.

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23 minutes ago, picosecond said:

2/10: OFF THE SHELF COMPONENTS

Gray market YM2151/3012 do not meet the criteria.  I am quite certain others will disagree with this opinion.

They don't meet it perfectly, but then again, Vera FPGA and YM2151 grey market, 65C02 stock, VIAs stock, glue logic stock, RAM stock, FlashROM stock ...

... 2/10 is a silly score to give on that basis. That's at least a C, so set it at 7/10.

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2 hours ago, BruceMcF said:

... 2/10 is a silly score to give on that basis.

The scale is wholly arbitrary so I don't see why any score should be labelled "silly".  I thought I was being generous.

Here's the thing:  I don't care at all about purity tests.  I care about building reliable computers.  Using these parts poses risks that nobody on the design team can quantify.  Maybe the supply will be great quality and they have no problems.  But if not, what then?

  • Pay someone to screen the parts?
  • Develop a test procedure (not so easy) and screen parts themselves?
  • Hope for the best and ship spares to kit builders who complain about no sound?
  • What about damaged but not dead parts that die some months after systems are shipped?

None of this matters for hobbyist builds.  All of it matters when shipping systems in quantity.  It's just not worth the risk to reputation and personal bank accounts to take chances with iffy semiconductors.  Maybe 2/10 was too generous.

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9 minutes ago, picosecond said:

The scale is wholly arbitrary so I don't see why any score should be labelled "silly".  I thought I was being generous.

Here's the thing:  I don't care at all about purity tests.  I care about building reliable computers.  Using these parts poses risks that nobody on the design team can quantify.  Maybe the supply will be great quality and they have no problems.  But if not, what then?

  • Pay someone to screen the parts?
  • Develop a test procedure (not so easy) and screen parts themselves?
  • Hope for the best and ship spares to kit builders who complain about no sound?
  • What about damaged but not dead parts that die some months after systems are shipped?

None of this matters for hobbyist builds.  All of it matters when shipping systems in quantity.  It's just not worth the risk to reputation and personal bank accounts to take chances with iffy semiconductors.  Maybe 2/10 was too generous.

Yaaaaaaawn we already know that if the YM2151 supply craps out then they'll roll an FPGA daughterboard. Literally posted by Lorin less than 48 hours ago.

2/10 is patently vindictive. 7/10 is reasonable. If you're that convinced that the FPGA YM2151 will become mandatory, maybe a 6/10.

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38 minutes ago, StephenHorn said:

If you're that convinced that the FPGA YM2151 will become mandatory, maybe a 6/10

Supply crapping out and poor quality parts are different things.

FPGA YM2151 gets 10/10 from me.  Then it would be 100% new, off-the-shelf parts.  I don't care if parts are fixed-function vs programmable.  I do care if they are new vs used.  If a suitable new fixed-function part isn't available FPGA is a great solution.

BTW, despite not posting here often I do read every one of Lorin's posts.  Don't assume I am uninformed because my perspective is different from yours.

 

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7 hours ago, rje said:

When I compare this with, for instance, Ben Eater's 6502 breadboard, or the FW8B PET single board, or the PE6502, I see this:

10/10 Off the Shelf

FW8B PET and PE6502 both use microcontrollers for video. I think David would prefer this less than FPGA.

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9 hours ago, picosecond said:

The scale is wholly arbitrary so I don't see why any score should be labelled "silly".  I thought I was being generous.

Here's the thing:  I don't care at all about purity tests.  I care about building reliable computers.  Using these parts poses risks that nobody on the design team can quantify.  Maybe the supply will be great quality and they have no problems.  But if not, what then?

It IS an ordinal scale. 2/10 is saying that is there is only one step between this board and not meeting the criteria in any way whatsoever, and seven steps between this board and meeting the criteria perfectly.

I don't have any experience buying from these channels, but since the source will be Chinese, they are indeed likely to prescreen the chips to sort between those they sell to their ongoing customers and those they sell to hucksters selling to people gambling on components on eBay. If someone with experience buying from the first channel reports that they have good experience, I don't have any reason to assume that that will change for these orders.

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14 hours ago, rje said:

A scorecard.

The CPU at 65C02 @ 8Mhz doesn't tick any of the boxes other than "6502 compatibility" I suppose. It's too old, too limited and too slow. You can solve the problems either by having a wide address space or speeding it up, but at the moment, it falls between two stools. I'd give it 4/10

The RAM may be there numerically but that's about it, at best you are squeezing a quart into a pint pot with expensive and messy bank switching. I'd give it 5/10

VERA is very good at some things and terrible at others, mostly because of the pipe access to the internal RAM. If it was on the bus directly addressable, it would be a 9 or 10, There's no point in putting a Model T engine in a Ferrari chassis.  Its a 5/10

The operating system is the same as the C64 effectively, the same as the PET, because Tramiel always wanted to spend as little as possible. It's not too bad, but loses all its points because it's still Microsoft BASIC with GOTO GOSUB 2 letter variables etc. in something which is supposed to encourage programming. Precompilers lose the immediacy. 0/10.

You've missed the one very important thing. Affordability. The original plan was to produce something for £30 ish. This is probably optimistic - it would be just about doable on a cheap mass produced Chinese FPGA board, but probably £50 would be a minimum. This is going to be nowhere near that.

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On 1/22/2021 at 6:46 PM, paulscottrobson said:

The CPU at 65C02 @ 8Mhz doesn't tick any of the boxes other than "6502 compatibility" I suppose. It's too old, too limited and too slow. You can solve the problems either by having a wide address space or speeding it up, but at the moment, it falls between two stools. I'd give it 4/10

On the question of whether it falls in line with:

QUOTE: I would want the CPU to be 6502 or compatible, such as 65816.  However, I’d be fine with the traditional 6502.  I would prefer a faster clock speed, such as 8 Mhz or better.  That way people could write code in BASIC and it would actually run fast enough to be useful.  As long as we aren’t stuck using something like Commodore’s VIC or VIC-2 chips, then this shouldn’t be a problem. UNQUOTE

... I don't see how it can be scored as less than "complies perfectly" unless they fail to get it running at 8.33MHz and have to settle for 6.25MHz.

If you are simply saying your dream 8bit computer is a 16bit computer, well, no set of feasible design goals pleases everyone.

Edited by BruceMcF
fix editing mistake
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@paulscottrobsonA straight to the point analysis. And a pretty darn good.

My 2cents:
I'm seeing a lot of system nowadays using a serial intf and they're pretty efficient. Therefore, I'm not about this being a prob with VERA.... just a feeling here. I may be wrong.
Also, the point is to feed the beast with data and let it deal with it. So the more functions VERA has the better

Ah... the OS or what is called OS. more a BIOS than a real OS. It has always been the poor child in the C64 realm.
But...... we are here to change that ! 😉 As developers, we can do whatever we want. So, please, guys, let's do something about it 😉

 

ps: about the BASIC, it's far from the best version..... but then again, this is software. It could be easily changed. Some work to do, yes.
For instance, what about the EhBasic. Same background, that is MS, but with some nice features. One being the easiness to extend.

Edited by kktos

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Oooh. Indeed. Someone was busy 😉
Nice piece of software. A little challenging to port to x16.... but could be worth it.

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I actually rather like there isn't much of an "OS" on the x16. I think it fits the heritage and goals of the machine nicely. But GEOS will be part of the kernel so that's a potential option there (though you currently need the GEOS disk images - and I haven't tried it yet).

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7 minutes ago, m00dawg said:

I actually rather like there isn't much of an "OS" on the x16. I think it fits the heritage and goals of the machine nicely. But GEOS will be part of the kernel so that's a potential option there (though you currently need the GEOS disk images - and I haven't tried it yet).

Hum... ok, I got what your saying. And yes, I do agree.
I'm merely thinking about Disk Operating System rather that a complete OS.... I'm a apple // fan and as far as I can remember, I always used the computer with a dos. seems to be the minimum
GEOS, on the other hand, is a tad too much :):) That's the C64 trying to mimic the Mac with UI and more..... Wrong target.

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4 hours ago, BruceMcF said:

If you are simply saying your dream 8bit computer is a 16bit computer, well, no set of feasible design goals pleases everyone.

Pretty much this. But more generally, if folks want to dunk on the X16's design goals, at least be up front about that.

I think rje's scorecard is pretty reasonable. I would probably be a little harsher about "off the shelf components", in part because of the necessary FPGA daughterboard solution for the VERA, but also because I can at least agree that the YM2151 shouldn't get full credit, as it's no longer in production. If there'd been an in-production audio chip and the VERA had been limited to only video, then I would have agreed with 9/10.

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I have to admit that the engineer in me is looking at the design so far and thinking that they should just throw everything possible into a FPGA. You can put a 6502 in a FPGA fairly easily, along with the RAM and much of the glue logic, and it would make redesigning the memory banking system easier. It might even be possible to implement a 65816 core which would give you a larger memory space and eliminate the need for banking, and allow for features like direct access to the VRAM through the memory bus.

Of course, that would get even further away from the actual original goals of the X16 project, and I can understand why they're not doing it. It is something that I might look into implementing myself as a side project at some point in the future.

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5 hours ago, BruceMcF said:

On the question of whether it falls in line with:

QUOTE: I would want the CPU to be 6502 or compatible, such as 65816.  However, I’d be fine with the traditional 6502.  I would prefer a faster clock speed, such as 8 Mhz or better.  That way people could write code in BASIC and it would actually run fast enough to be useful.  As long as we aren’t stuck using something like Commodore’s VIC or VIC-2 chips, then this shouldn’t be a problem. UNQUOTE

... I don't see how it can be scored as "complies perfectly" unless they fail to get it running at 8.33MHz and have to settle for 6.25MHz.

If you are simply saying your dream 8bit computer is a 16bit computer, well, no set of feasible design goals pleases everyone.

I actually agree with this. "BASIC could run fast enough to be useful". This BASIC can't. For example, look at the well done BASIC Boulderdash. With a faster CPU you could actually do it without the limitations put on it to make it work fast enough. It doesn't have to be much faster, just maybe 3 or 4 times faster (or you could have a 65816 which would roughly double the speed).

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3 hours ago, ellindsey said:

I have to admit that the engineer in me is looking at the design so far and thinking that they should just throw everything possible into a FPGA. You can put a 6502 in a FPGA fairly easily, along with the RAM and much of the glue logic, and it would make redesigning the memory banking system easier. It might even be possible to implement a 65816 core which would give you a larger memory space and eliminate the need for banking, and allow for features like direct access to the VRAM through the memory bus.

Of course, that would get even further away from the actual original goals of the X16 project, and I can understand why they're not doing it. It is something that I might look into implementing myself as a side project at some point in the future.

I think the original goals I think are noteworthy and certainly, much like Ben Eater's 6502 work, it's nice to be able to see how some of this stuff interacts in a way that an FPGA would hide. We already have complicated computers sitting on our desks and floors (mine is all fancy and watercooled even awyiss!). Basically this starts down the path to the previous discussions about this which often ended up effectively defining a modern computer. David draw a nice line in the sand as it were when he based the design off the VIC-20 with as much as possible of it being on real chips. This is, in it of itself, a sort of "limitations breeds creativity" right from the start, even in the design of the computer.

Now that said, though lines can blur here, the C256 is a 65C816 baremetal hobby computer chock full of FPGAs. And it is a beautiful design it its own right for sure! It's very different from the X16 - sort of more Amiga-esque in a way. Could be worth a look though if you're really all in on the FPGAs.

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A few thought on OS vs. living from a Basic command interpreter:

If a modern-ish GEOS style can be optionally banked in/enabled for those that really want that [not me], than both camps will be satisfied (one that wants a contiguous memory map without banking business and one that is willing to manage RAM and forfeit some always in ROM code/OS).  

I'm nowhere near well-read/informed when it comes to how MMU type functions will manage the banking of the memory north of the 64K boundary;  Maybe the team here has already worked that out or maybe it's roll your own e.g. plug a number into a single memory location to determine which bank of 8 or 16k overlay a portion of the contiguous 'main' memory.

  • But as a recent Apple II convert, I'm struck by the difference of environments, capabilities, product ecosystem, longevity, and market value of Apple products.
  • Built in monitor that Commodore for some reason dropped after the PET is awesome
  • Zero disk capabilities without booting into "DOS" is nuts.  Makes you really respect the afterthought of a command channel to IEC serial devices
  • Applesoft Basic with plenty of extensions for graphics and what not, mixed mode screens, etc. but nothing other than sluggish bit mapped graphics with PET style 'sound' and fake color = madness
  • But on the other hand, I bought an Apple II+ with a language card, drive, Disk ][ drive, Epson printer interface for less than I can buy a C64 with a broken keyboard.  Since picked up an 80 col card and a SuperSerial adapter.

My Commodore 128 (mounted to the wall in my STEM Lab as me and our 11 yr old call it) had sprite editor and a bunch of other tricks that I never even bothered to use.

So in short, do include the xtra niceties of some extended Basic commands and disk utilities, a ML monitor and an image, char set, and tile editor if that could be omnipresent and allow a rom banking (probably too late) for fancIER GEOS.

Would love to see the MVP, EPICs, and jump in on your Sprint planning PBR and demo sessions; because scope creep coming from guys like me must be fun, considering  : )

Everything else is awesome.  Looks like the machine is ticking all the boxes ... but please hurry : )

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22 hours ago, kktos said:

Hum... ok, I got what your saying. And yes, I do agree.
I'm merely thinking about Disk Operating System rather that a complete OS.... I'm a apple // fan and as far as I can remember, I always used the computer with a dos. seems to be the minimum
GEOS, on the other hand, is a tad too much :):) That's the C64 trying to mimic the Mac with UI and more..... Wrong target.

If there is a setting for whether to run an autostart program in the persistent memory of the clock chip, then having the autostart program run your disk operating system of preference would seem to be an option.

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18 hours ago, ellindsey said:

I have to admit that the engineer in me is looking at the design so far and thinking that they should just throw everything possible into a FPGA.

They are going to do that, aren't they? It's just going to be implementing the features in the kit build able reference design.

As far as "allowing" them to change the memory map, there's no gain in that if they don't WANT a more intricate memory map, and from the discussion at the time the new memory map was decided on, they are implementing what they want, as opposed to being forced to accept what they can get.

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Regarding sound.  I know many people want and know how to use the YM synth -- 8BG included -- but even without it, the PSG + PCM fits the "sound of some kind" requirement.

 

Meanwhile, I understand Paul's points:

Quote

The [...] 65C02 [is] too old, too limited and too slow. You can solve the problems either by having a wide address space or speeding it up  [...]

If [VERA] was on the bus directly addressable [...]

The operating system is [...] still Microsoft BASIC with GOTO GOSUB 2 letter variables etc. in something which is supposed to encourage programming. Precompilers lose the immediacy. [...]

[It loses on] Affordability. 

 

I would like Paul to start a new thread with his Dream Computer.  For the moment, though, we have enough information to make some starting assumptions.

His balance favors the programmer, with a flat memory, memory-mapped I/O model. 

1. The W65C816S fits the Apple IIgs world, still solidly in 1986.  $1 more than the 65C02.

2. You get speed (efficiency) and memory addressing space.   Same memory costs.

3. VERA can sit right on the memory bus.  Same VERA costs.

I suppose VERA and the CPU would have to split the clock for memory access.  Assuming VERA can run fast enough, then that's probably not a problem.  (I suppose things would run at about 7Mhz?)

4. An upgraded "immediate mode" programming environment.  The Structured BASIC that's being built for the X16 would probably be the solution.   Development time with QA.

5. Scrapping the current prototypes and starting over would be daunting.

 

I admit that the 16 bit CPU has all sorts of elbow room.  I can see the appeal.  It would solve some of MY programming problems.

 

 

 

 

Edited by rje

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