> Ok, why don't you open a new conversation, with the title "The ideal standalone Z80-compatible retro/homebrew computer" ?
>
> AgonLight is fit to be presented there...

AgonLight is also fit to be presented here.

Consider one more example: in former East Germany they manufactured
Z80 clone named U880. So you would exclude the machine fitted with U880
from this thread, because its CPU didn't have proud „Z80” print on its package?

I thought you were serious by stating:

”different opinions should always be acknowledged and accepted... and
I will also comply with this rule of common sense”

It seems I was wrong.

But OK, then leaving this thread to not bother you with different opinion. Bye!

On 21/08/2023 8:11 pm, Zbig wrote:
>> Ok, why don't you open a new conversation, with the title "The ideal standalone Z80-compatible retro/homebrew computer" ?
>>
>> AgonLight is fit to be presented there...
>
> AgonLight is also fit to be presented here.
>
> Consider one more example: in former East Germany they manufactured
> Z80 clone named U880. So you would exclude the machine fitted with U880
> from this thread, because its CPU didn't have proud „Z80” print on its package?
>
> I thought you were serious by stating:
>
> ”different opinions should always be acknowledged and accepted... and
> I will also comply with this rule of common sense”
>
> It seems I was wrong.
>
> But OK, then leaving this thread to not bother you with different opinion. Bye!

"please describe, in your opinion, which should be the hardware characteristics of
an "ideal" standalone Z80-based retro computer!"

I never heard of the Agon Light until you mentioned it. It's the only one that
got me interested enough to investigate it. So thanks for that.

> >
> > Consider one more example: in former East Germany they manufactured
> > Z80 clone named U880. So you would exclude the machine fitted with U880
> > from this thread, because its CPU didn't have proud „Z80” print on its package?
> >

@Zbig:

I wonder if you are really reading my messages, or only responding because you need to respond...
If you read more carefully my past messages, you would have noticed that I mentioned, in my 20 august message, this statement:

"Well, in my opinion, in this thread we should discuss only about standalone retro/homebrew computers provided with the Z80 CPU.
The "real" Z80 (Z84C00) or its "clones" (e.g. MK3880, LH0080, U880, MMN80CPU, ...) , with clock frequencies up to 20MHz.
Not Z180/Z280/Z800/R800/eZ80 ... "

There is an U880 clearly mentioned here... and you know why? Because I worked in the 80's with some East Germany manufactured computers... what about your past experiences related to East European Z80-based computers? Bulgarian, East-German, Romanian, Russian... ( I wrote real-time operating systems for Romanian computers... ).

But, it seems you are not really interested in the facts I mentioned, because you are targeting only one goal: "I am right, and you are wrong!"

As for AgonLight, see here: https://groups.google.com/g/retro-comp/c/nGfo3iKdZkY an opinion...

There are Pros, but also Cons...

But, again, in this conversation, in my opinion, we should talk only about Z80-based (NOT Z80-compatible) retro/homebrew computers.

My view on the terms Z80 & Z80-compatible is the following:

Z80 = "real" Z80 (Z84C00) or its "clones" (e.g. MK3880, LH0080, U880, MMN80CPU, ...)
Z80-compatible = Z180/Z280/Z800/R800/eZ80 (...and others)

Once again, as I already said:

"In my opinion, retro computing is a hobby, a recreational activity.
Any categorization, limits or boundaries should be considered indicative and relative only.
Other, different opinions should always be acknowledged and accepted... and I will also comply with this rule of common sense.
So, please continue sharing your thoughts here about THIS topic..."

The current topic is "standalone Z80-based retro/homebrew computers".
NOT "standalone Z80-compatible retro/homebrew computers"

Please, if some of you want to debate issues regarding "Z80-compatible retro/homebrew computers", or any other topic different from "Z80-based retro/homebrew computers", please do open a new Conversation, with an appropriate title, because I will not waste any more time responding to out-of-topic messages.

Ladislau

Ladislau has a lot of things right, Z80 based is not the same as Z80 compatible. Compatibility is a term that covers a broader spectrum, there can be Z80, "Super-Z80" like Z180, Z280, eZ80, hardware emulations on FPGA and software emulations on any other architecture.
Returning to the topic of the thread, I believe that there is no perfect Z80 computer, each has its limitations related to its purpose. You will need a different set up when you want to play games, a different set up to run CP/M, as well as a different set up to run MP/M. The low performance of the processor does not allow to build a universal computer as we know it from modern PCs. Yes, you can attempt to build one, but it will be a difficult task and quite expensive if you want to use chips from that era. I believe that any system running at a clock greater than 6MHz will give you a comfortable working environment with CP/M. Remember - the ZX Spectrum ran at 3.5MHz and provided a lot of entertainment.

On 22/08/2023 7:34 pm, Tadeusz Pycio wrote:
> Ladislau has a lot of things right, Z80 based is not the same as Z80 compatible. Compatibility is a term that covers a broader spectrum, there can be Z80, "Super-Z80" like Z180, Z280, eZ80, hardware emulations on FPGA and software emulations on any other architecture.

If 'Z80 based' is to mean 'Z80 only' it rules out the vast majority of
modern designs. For designers attractiveness lies is the possibility
of doing *more* than what was done 40 years ago. If what's offered now
not only gives better performance but is also designed to be backward
compatible, who wouldn't be interested? Let's not forget the Z80 itself
was a new processor built upon an old design and became popular for
that reason.

Why do you think it excludes most new projects? This year I designed two RCBus modules using the Z80. Also, a module on the Z280 supported by a contemporary AVR microcontroller was also created. One may wonder if such solutions can be called "retro", but certainly the Z80 modules are based on the Z80, and the Z280 is a Z80-compatible processor. The whole charm of such solutions lies in the use of technology from that period. A few years ago I designed a Z80 emulator running under CP/M, using all the modern advances on an ARM Cortex-M3 processor, and abandoned it because for me it was a dead end. I believe that the choice of components is an individual designer's choice and any solution is good, whether on Z80 or FPGA. Some will consider it right, others will question the sense of using a 1976 processor or using a GHz programmable array.

> Why do you think it excludes most new projects? This year I designed two
> RCBus modules using the Z80. Also, a module on the Z280 supported by
> a contemporary AVR microcontroller was also created. One may wonder
> if such solutions can be called "retro", but certainly the Z80 modules are
> based on the Z80, and the Z280 is a Z80-compatible processor.

I don't want to disturb anyone with my „different opinion” — so
the last word here. And actually it's not my word — but the word
of eZ80 creators and manufacturers. In the PDF document they released
they clearly stated:

„The eZ80™ is ZiLOG’s next-generation Z80™ processor. The eZ80 provides 16
times the performance of a traditional Z80. The multiple operating modes of the
processor allows Z80 and Z180 code to be run without change in the same appli-
cation with new code [..] At the same time, the eZ80 remains 100% Z80 code-compat-
ible, reducing customer development time. [..]
Z80 High-Performance Microprocessor Core. The eZ80 is one of the fastest 8-
bit CPUs available today, executing code 4 times faster than a standard Z80 oper-
ating at the same clock speed. [..]
The eZ80 is ZiLOG’s fourth-generation Z80 processor core.”

I could quote even more — but I believe it's quite enough. So the creators themselves
call eZ80 simply „next-generation Z80”, but you and Ladislau „know better”.

BTW: as I've found out, DDR-manufactured U880 wasn't actually exact clone of Z80:
„The U880 is an unlicensed clone of the Zilog Z80 microprocessor, also supporting
illegal opcodes and bugs, except for very minor differences like not setting the CY
flag for the OUTI command (when L goes zero).” — so you would include that one
into your list — although it was merely 99% compatible, at most — and you're willing
to exclude „next-generation Z80” (which hasn't such issues) only because it's newer?
Then maybe 8 Mhz clocked Z80 also should be excluded?

OK, „over and out”.

How do I understand "know better"? You think the eZ80 is the only right choice, then so be it, it is your opinion and I don't necessarily have to agree with it. The AgonLight is a great computer, but it is not the only right choice for Z80 supporters. The discussion is starting to resemble direct marketing - either AgonLight with eZ80 or you don't know. Everyone has different expectations from such a system and everyone can find what suits them. The performance argument does not appeal to me, there are definitely faster processors being produced nowadays and costing far less. If I want to play with something modern, I will make a flashing LED on RISC-V for $0.1 ;-)

> How do I understand "know better"? You think the eZ80 is the only right choice, then so be it,

You've completely missed the point; you may want to read again,
what I wrote — but this time SLOWLY AND WITH UNDERSTANDING.

Cheers! :)

On Tuesday, 22 August 2023 at 13:56:30 UTC+1, Tadeusz Pycio wrote:
> How do I understand "know better"? You think the eZ80 is the only right choice, then so be it, it is your opinion and I don't necessarily have to agree with it. The AgonLight is a great computer, but it is not the only right choice for Z80 supporters. The discussion is starting to resemble direct marketing - either AgonLight with eZ80 or you don't know. Everyone has different expectations from such a system and everyone can find what suits them.. The performance argument does not appeal to me, there are definitely faster processors being produced nowadays and costing far less. If I want to play with something modern, I will make a flashing LED on RISC-V for $0.1 ;-)

In my mind (in the context of 8080/z80 etc) , a computer is only a great computer if it supports CP/M 3 as well as CP/M 2.2 to take advantage of the extra horsepower, if it has those beefy chips like eZ80. The CP/M 3 disk buffering is advantageous. I'm not aware it is implemented on AgonLight yet.
And it becomes truly great when RomWBW runs on it.

Richard

On 22/08/2023 9:44 pm, Tadeusz Pycio wrote:
> Why do you think it excludes most new projects? This year I designed two RCBus modules using the Z80. Also, a module on the Z280 supported by a contemporary AVR microcontroller was also created. One may wonder if such solutions can be called "retro", but certainly the Z80 modules are based on the Z80, and the Z280 is a Z80-compatible processor. The whole charm of such solutions lies in the use of technology from that period.

The ez80 is obviously compatible too. I'm not a collector of retro hardware. The charm
for me is the software of that period. Software small enough that anyone can grasp it.
What I never care for were the hardware limitations - the slow CPUs and disk drives.
I've little hankering to spend several hundred dollars on a backplane of 'Z80' cards to
recreate a slow vanilla CP/M system I owned 35 years ago. I still enjoy developing
software on CP/M which is why I won't do it on ancient hardware. If it were just about
CP/M then I'd hardly need an Agon Lite board. In addition to the ez80's better speed,
there's a new OS and video opportunities for retro Z80 language enthusiasts to play with.
Granted it's early days. What's less likely is the project getting this far had it been
a stock Z80 under the hood.

Why spend the money then? Nowadays, there are excellent PC emulators that far outperform any Z80-compatible hardware solution. If we feel the need for separate hardware, we can emulate the entire CP/M environment on an inexpensive ESP32, which can also be found on AgonLite, using the RunCPM project. In each of these examples, we can enjoy convenience and performance. What distinguishes these solutions from the typical "slow" modular Z80 system is the lack of expandability. It is a closed system, with no freedom to add any extensions. Therefore, for me personally, there is no difference between closed hardware solutions and emulators, and if I had to choose between the two, I would prefer the emulator (which I often use when I don't have access to my hardware).

On 23/08/2023 4:41 am, Tadeusz Pycio wrote:
>
> Why spend the money then? Nowadays, there are excellent PC emulators that far outperform any Z80-compatible hardware solution.

I'm still looking for that 'excellent' MS-DOS emulator (which I'll use with MYZ80)
that conveniently interfaces with Windows.

> If we feel the need for separate hardware, we can emulate the entire CP/M environment on an inexpensive ESP32, which can also be found on AgonLite, using the RunCPM project. In each of these examples, we can enjoy convenience and performance. What distinguishes these solutions from the typical "slow" modular Z80 system is the lack of expandability. It is a closed system, with no freedom to add any extensions.

If hardware control is really of interest, there's Arduino where the add-ons are
cheap, prolific and easier to program due to the pre-written routines, large
knowledge and user base.

Whether I'd run CP/M on the Agon is questionable. The latter is closer to the
likes of Amstrad and Spectrum and where I see any development happening.

> Why spend the money then? Nowadays, there are excellent PC emulators that far outperform any Z80-compatible hardware solution.

Surely you never heard of Low Fat Computing.

> Therefore, for me personally, there is no difference between closed hardware solutions and emulators, and if I had
> to choose between the two, I would prefer the emulator

Agon Light is open-sourced both hardware and software.

On Wednesday, 23 August 2023 at 07:10:31 UTC+1, dxforth wrote:
> I'm still looking for that 'excellent' MS-DOS emulator (which I'll use with MYZ80)

try this http://www.vdosplus.org/

On 25/08/2023 4:37 pm, Chris Syntichakis wrote:
> On Wednesday, 23 August 2023 at 07:10:31 UTC+1, dxforth wrote:
>> I'm still looking for that 'excellent' MS-DOS emulator (which I'll use with MYZ80)
>
> try this http://www.vdosplus.org/

Thanks. MYZ80 boots on it but doing anything cause a crash e.g. DIR gives me a
page then freezes. Original DOSBOX has its quirks but generally works.

On Friday, 25 August 2023 at 11:39:15 UTC+1, dxforth wrote:
> On 25/08/2023 4:37 pm, Chris Syntichakis wrote:
> > On Wednesday, 23 August 2023 at 07:10:31 UTC+1, dxforth wrote:
> >> I'm still looking for that 'excellent' MS-DOS emulator (which I'll use with MYZ80)
> >
> > try this http://www.vdosplus.org/
> Thanks. MYZ80 boots on it but doing anything cause a crash e.g. DIR gives me a
> page then freezes. Original DOSBOX has its quirks but generally works.

I know I am OOT, but, there is another MSDOS 'emulator' for x64 windows..

http://takeda-toshiya.my.coocan.jp/ has an MSDOS player (an .exe that runs old MSDOS .exe)
There is a CP/M player as well there.
HTH

On Tuesday, August 22, 2023 at 2:41:45 PM UTC-4, Tadeusz Pycio wrote:
> Why spend the money then? Nowadays, there are excellent PC emulators that far outperform any Z80-compatible hardware solution. If we feel the need for separate hardware, we can emulate the entire CP/M environment on an inexpensive ESP32, which can also be found on AgonLite, using the RunCPM project. In each of these examples, we can enjoy convenience and performance. What distinguishes these solutions from the typical "slow" modular Z80 system is the lack of expandability. It is a closed system, with no freedom to add any extensions. Therefore, for me personally, there is no difference between closed hardware solutions and emulators, and if I had to choose between the two, I would prefer the emulator (which I often use when I don't have access to my hardware).

But the emulators are not "closed" -- I added AM9511 to RunCPM and other emulators. And, other bits and bobs can be added. I do use an "Altair-Duino" for the blinking lights -- yes, I used an Altair back in the day, but really prefer the smaller Altair-Duino. Part of the charm (for me) _is_ the speed (rather the lack thereof) Between 2Mhz and 64K, I think I have all the old-timey bases covered.

I really don't understand the urge to "push" a Z80 to 20, 50, 100Mhz and 128KB, 4MB of memory. The fun is the lack of memory and lack of speed (for me). I have been contemplating getting an old-timey ASR-33 teletype and an old-timer cassette recorder for the "real feeling". If I actually need to run a word processor, I *could* do most of what I need with WordStar 3.3, but I need to use Microsoft 365, Google Docs, etc. to actually collaborate with others (with a side of OpenOffice). Doesn't actually add that much, but it informs that the bulk of computing has been to make it accessible.

So, what is the "perfect Z80" for me? 32k to 128k of RAM, clock from 2 to 6MHz, serial ports (up to 38400 baud). CP/M 2.2 or 3, with VT52 terminal (for maximum WordStar 3.3 compatibility -- note that ANSI terminals cannot run SpelStar properly! -Real VT100s can be coerced),
Tek 4100 for graphics, Diablo 630 for text printing.

128K of memory does allow for a bit of bank-switching, which is useful for MP/M. I would want a 56/8 switching configuration. Or 56/4/4. Since I use and write software for CP/M 2.2, I don't need much beyond that. As to speed? 2Mhz is ok; same as the old Altair, 4Mhz was a standard for a bit, and 6MHz always felt lie "turbo" to me. If I need more, I just use a modern system..

I love the blinking lights of the Altair / Altair-Duino -- warm and comfortable. My Altar-Duino lives just under my 34" Ultrawide LG monitor. Usually running "kill-the-bit" or some such for visual amusement as I am working.

On Saturday, August 26, 2023 at 9:40:50 AM UTC-7, fridtjof.ma...@gmail.com wrote:

I agree with most of what you posted, but ...

> I really don't understand the urge to "push" a Z80 to 20, 50, 100Mhz and 128KB, 4MB of memory.

I like to fool around with the old compilers (C, FORTRAN, PL/I, etc.). At 4 MHz, using them can be quite painful. So that is why I built myself a very small Z80 SBC (roughly 4.5" x 4") that runs at 20 MHz and can be powered from the USB port that acts as the console (at 115k baud). It uses a stock CMOS Zilog CPU and SIO, runs CP/M 2.2, and has a compact flash interface that provides sixteen 8 MB "disks". I'd post a photo, but I don't see any way to do that here. It has 32k of EEPROM and 128k of SRAM. I suppose that would support some sort of bank switching, but I've not experimented with that nor have I seen the need to do that .... just yet. The second serial port of the SIO is available for other serial devices. All of the legacy CP/M software that I like to use fits on this little speed demon, and provides a *very* comfortable and responsive CP/M environment!

Roger

> So, what is the "perfect Z80" for me? 32k to 128k of RAM, clock from 2 to 6MHz, serial ports (up to 38400 baud). CP/M 2.2 or 3, with VT52 terminal (for maximum WordStar 3.3 compatibility -- note that ANSI terminals cannot run SpelStar properly! -Real VT100s can be coerced),

Then you'll love good old Commodore 128 in its CP/M mode: running at 2 MHz, 128 kB, CP/M 3, Wordstar of course can be run etc. Everything as you wish.

On Saturday, August 26, 2023 at 9:40:50 AM UTC-7, fridtjof.ma...@gmail.com wrote:

>
> I really don't understand the urge to "push" a Z80 to 20, 50, 100Mhz and 128KB, 4MB of memory. The fun is the lack of memory and lack of speed (for me). I have been contemplating getting an old-timey ASR-33 teletype and an old-timer cassette recorder for the "real feeling". If I actually need to run a word processor, I *could* do most of what I need with WordStar 3.3, but I need to use Microsoft 365, Google Docs, etc. to actually collaborate with others (with a side of OpenOffice). Doesn't actually add that much, but it informs that the bulk of computing has been to make it accessible.
>

The 20MHz Z80 will do 20MHz without pushing. :)

Greg

On 27/08/2023 9:03 am, Zbig wrote:
>
> Then you'll love good old Commodore 128 in its CP/M mode: running at 2 MHz, 128 kB, CP/M 3, Wordstar of course can be run etc. Everything as you wish.

Not for me. Even a 4MHz Z80 with regular disk drives would feel like purgatory
at this point of time. Not even sure I could manage a 'standalone' computer any
more.

> If hardware control is really of interest, there's Arduino where the add-ons are
> cheap, prolific and easier to program due to the pre-written routines, large
> knowledge and user base.

Not only that; AmForth and Flashfort work even on little ATmega328P
(the one in Arduino Uno) just fine — and AVR's assembly language
resembles to some extent the one of 8080/Z80:
http://www.avr-asm-tutorial.net/avr_en/micro_beginner/instructions.html

On 28/08/2023 1:48 am, Zbig wrote:
>> If hardware control is really of interest, there's Arduino where the add-ons are
>> cheap, prolific and easier to program due to the pre-written routines, large
>> knowledge and user base.
>
> Not only that; AmForth and Flashfort work even on little ATmega328P
> (the one in Arduino Uno) just fine — and AVR's assembly language
> resembles to some extent the one of 8080/Z80:
> http://www.avr-asm-tutorial.net/avr_en/micro_beginner/instructions.html

Even if one isn't immediately attracted, it's amazing how 'cheap and prolific'
grows on one. In some ways Arduino/AVR was too successful as it got the
attention of chip counterfeiters.

On Tuesday, July 25, 2023 at 11:30:52 AM UTC+2, ladislau szilagyi wrote:
> Hi all,
>
> please describe, in your opinion, which should be the hardware characteristics of an "ideal" standalone Z80-based retro computer!
>
> By hardware characteristics, I mean: processor speed, RAM/EPROM size, storage media (type, storage capacity), keyboard interface, video screen interface, etc.
>
> thanks,
> Ladislau
Ideal for me would be if it doesn't use any chip more powerful than a Z80, and, of course only one Z80.
Even if it makes communication with outside more difficult. The keyboard should be mechanical, and look like a Kaypro II or ADM-3A.