Questions about the Memotech MTX that you were too afraid to ask...

Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

gunrock wrote: 06 Sep 2022 16:11 Question: Why hasn't anyone produced a modern copy of Speculator?

This community is still thirsty for software and the Spectrum has tons. Dave, I know, has a Speculator and so do others here probably. Tony Brewer, the developer, is part of the community and would maybe provide "spiritual guidance" (for want of a better term), so why haven't we created a Speculator+ or SpeculatorNG?

I think Andy Key's Rememorizer had Speculator functionality, so there doesn't seem to be an intellectual property objection, as far as I can see.

No appetite for Spectrum games? Or are the limitations of the Speculator producing a sub-standard experience when compared to a real Spectrum/Spectrum emulation/modern re-imaginings like the Spectrum Next, etc?
Apologies for the slow reply, I've been busy with other things recently. Here's another question: do you really want to see just how sub-standard the Speculator is?

I lost the original MTX Speculator source files, however I managed to recreate them completely from the Einstein version. If the Rememorizer requires modified Speculator files in order to emulate the Speculator then this could be done. The extra Rememorizer screen hardware could help increase the refresh frequency but this might require a significant rewrite.

I suppose I should think about making the source files public-domain. Before then, I could make small changes to the code if I am told what functionality needs to be modified. Maybe a new thread should be created.

Rememorizer link:
http://nyangau.org/rememorizer/rememorizer.htm
User avatar
gunrock
Posts: 245
Joined: 28 Oct 2020 21:17

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by gunrock »

Hi Tony,

Thanks for your reply. I hope you didn't take my question as disrespectful. I wasn't suggesting the Speculator was sub-standard (maybe a poor choice of words), or denigrating the quality of your work. I was wondering why we hadn't seen a newer version of it, so was suggesting that perhaps it fell short when compared with emulation or fpga recreation. If it came across as offensive Tony, I apologise. I've only ever read reviews of the Speculator, so no actual experience of one.

Of course, losing the source would explain the reason why we haven't seen a new, updated version available. Thanks for answering, I think there would be interest in open sourcing the code. I know for a fact there is interest in the (potentially) even smaller community of Einstein users, because they wrote about it recently in their forums. Apparently, the Einstein version of Speculator goes for several hundred pounds on Ebay these days.

https://www.robheaton.co.uk/tatung/view ... t=116#p968
Last edited by gunrock on 25 Sep 2022 07:29, edited 1 time in total.
Steve G
Danish Memotech MTX 512, MFX and loving it
Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

Emulating a 3.5 MHz Spectrum on a 4 Mhz MTX is rather optimistic and the effective Spectrum clock is roughly 2.4 MHz. The Speculator outputs 1/6th of the display every interrupt to the VDP, therefore display refresh is 50/6 = 8.33 Hz. That's definitely sub-standard but it's the best I could do at the time. On the plus side (some) Spectrum games could be played on the MTX.

If the Rememorizer with its extra hardware could handle 1/3rd of the display per interrupt then refresh would be nearly 17 Hz, which would look a lot better. I recreated MTX source files some years ago. What is the situation with the Rememorizer and Speculator? Never been tried because software needs changing? Others are welcome to chime in.

The Spectrum ROM has been made public-domain since I designed the Speculator. If the Rememorizer could switch the ROM/RAM page automatically when opcode is fetched from address 0066H after NMI then ZX BASIC could run.
User avatar
Dave
Posts: 1280
Joined: 11 Aug 2012 18:16
Contact:

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Dave »

Tony Brewer wrote: 25 Sep 2022 00:29 What is the situation with the Rememorizer and Speculator? Never been tried because software needs changing? Others are welcome to chime in.
Hi Tony

Not sure what you meant by this? Andy does have a version of Speculator running in REMEMOrizer V3. With your help Andy could probably improve it, assuming that he had the time and inclination to modify the firmware for existing users.As with all of Andy’s stuff, the firmware is open source, so it could be worked on by others if Andy didn’t have the time/inclination.

Additional REMEMOrizers are probably not going to be available as, according to his website, Andy has no plans to make any more. I think this is probably due in large part to the FPGA board that he used no longer being available, so new hardware would be needed for an updated REMEMOruzer

Regards
Dave
Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

Dave wrote: 25 Sep 2022 08:49
Tony Brewer wrote: 25 Sep 2022 00:29 What is the situation with the Rememorizer and Speculator? Never been tried because software needs changing? Others are welcome to chime in.
Hi Tony

Not sure what you meant by this? Andy does have a version of Speculator running in REMEMOrizer V3.
Thanks for the info, Dave. So you've seen the Speculator running with Rememorizer?
User avatar
Dave
Posts: 1280
Joined: 11 Aug 2012 18:16
Contact:

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Dave »

Hi Tony,

I’ve not gotten around to trying it, my comments are based on Andy’s web page :

http://www.nyangau.org/rememorizer/rememorizer.htm

In case I wasn’t clear, the original Speculator hardware is emulated by REMEMORizer, Andy’s description has a little detail on how it is implemented

Regards
Dave
Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

I asked whether Speculator has been tested with Rememorizer because Andy says:
The original Speculator hardware partially address decodes ports x11xxxxx and xxx11111 binary, and the original Speculator code tests all these port ranges. We therefore require modified Speculator code which doesn't test everything, much as the Tatung Einstein version didn't.
http://www.nyangau.org/rememorizer/hard ... speculator

My bolding. I'm looking at relevant source file now and I could change the port testing code.
User avatar
Dave
Posts: 1280
Joined: 11 Aug 2012 18:16
Contact:

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Dave »

I took that to mean that Andy had modified the code, the "we", being him modifying the code to get Speculator working with REMEMOrizer, but perhaps he hasn't

He does say "REZSPEC.COM is the REMEMOrizer ZX Spectrum Emulator, written using ideas and code from Z2 in the Z ZX Spectrum Emulator, but written to exploit REMEMOrizer with bitstream r3 or later. This later REMEMOrizer variant can provide ROM 2 support (thus providing a space for the REZSPEC code to sit) and includes Speculator hardware support."
Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

I'm thinking about creating RESpectipede, a version of the Speculator software that runs Spectipede on REMEMOrizer r3 with no menu and no cassette loading if there is any interest. Would give people with this hardware a taste of the Speculator. No promises about when it might be ready.

Video of Spectipede on ZX Spectrum:
https://www.blogger.com/video.g?token=A ... 282fJk4I9A
Tony Brewer
Posts: 108
Joined: 08 Jan 2014 20:50

Re: Questions about the Memotech MTX that you were too afraid to ask...

Post by Tony Brewer »

gunrock wrote: 24 Sep 2022 22:36 I know for a fact there is interest in the (potentially) even smaller community of Einstein users, because they wrote about it recently in their forums. Apparently, the Einstein version of Speculator goes for several hundred pounds on Ebay these days.

https://www.robheaton.co.uk/tatung/view ... t=116#p968
I joined the Tatung forum but I've been waiting a couple of days to be approved so I can't login. I might have some Einstein Speculator boards. Perhaps you could mention both points on the forum for me? Thanks.
Post Reply