The Sinclair QL Forum

Dave wrote:All that matters is that there's a continuous flow of available hardware to satisfy existing and returning QLers. Peter has an exceptionally good track record with this.

Thanks for the flowers Dave. But this is the first time I made a wrong major design decision. This does not feel like Q40, Q60, QL-SD or Q68. Mind you, I designed a mainboard replacement for the QL, which brought up many challenges. And now all replies say "I want to use it outside the QL". Can you imagine what a waste of precious time that is and how depressing it feels?

I don't need to imagine.

Designing a string of potential products, and then a certain friendly Russian releases the exact same thing before I can even get it tested properly. I'm not knocking Tetroid, and he actually gets stuff out - but the closest I've been is within a few weeks of being ready, ordered bulk parts, and then *poof* Tetroid releases agood enough item that makes mine redundant.

It's heartbreaking.

But you have what you have. For all people say they want X, when you offer them Y they want it too. They just don't know how to express a preference without it being black and white.

Do your thing.

Side question. On the Q40 and Q60, how did you handle the CPU caches? Disabled? Instruction cache only? SMSQ/E mods? I am curious because I am trying to work out the most beneficial cache options on a 68EC030 running at least Minerva.

Peter wrote:But this is the first time I made a wrong major design decision.

Not in my opinion. I too would like a replacement board which fits into the original QL. Keep up the good work!

Dave wrote:Side question. On the Q40 and Q60, how did you handle the CPU caches? Disabled? Instruction cache only?

I usually run it in copyback mode. Enabling copyback gives substantial speed increases. Writing to a memory address will write to the cache, but not to memory until absolutely necessary. So cache and memory are rarely in sync. Some programs need to be patched before they will work with copyback enabled. As far as I know, Qliberated programs only work with writethrough cache. WIth writethrough cache, writing to a memory address writes both to the cache and to memory, so cache and memory are always in sync. It is the save default for poorly written applictations. Of course, hardware registers have to reside in non-cacheable areas.

Dave wrote:SMSQ/E mods?

SMSQ/E and QDOS Classic both have specific have support for the 68040/68060 caches.

Dave wrote:Designing a string of potential products, and then a certain friendly Russian releases the exact same thing before I can even get it tested properly. I'm not knocking Tetroid, and he actually gets stuff out - but the closest I've been is within a few weeks of being ready, ordered bulk parts, and then *poof* Tetroid releases agood enough item that makes mine redundant.

That sucks. I think at one point you were designing a replacement motherboard and Tetroid did as well. Did anything ever come of these?

At least the QL community, albeit is small, tries to get along. I find it funny there's someone on the PiStorm Discord forum who claims we are a litigious bunch just because we aren't willing to just share software that's still not publicly available. That's someone posting on a forum based mostly on Amiga, which has like the longest running lawsuit in the history of tech lawsuits :-/

That's what's hard. I really respect Tetroid's work and what he has done. I also feel like we need to co-operate and support each other a bit more (but then, the weakest contributor would say that!)...

Yes, I designed an "Issue 8" board. It suffered terribly from feature creep, but also became something quite good. The basis of it works. The finery doesn't.

It's simply not relevant in world where the Q68 and Tetroid's improved clone exist.

Hi,

Why not release the designs into the public domain, it looks like there are other people who are interested in QL hardware development.

My PiStorm installation is on hold, I found my Amiga A500 PSU is not working, looks like a Capacitor problem, so another piece of electronic equipment to repair. Or I could convert an ATX/AT PSU to work with the Miggy...

Derek_Stewart wrote:I have a PI Zero 2 ready to be fitted as Pi3A is very rare.

If you act quickly they have some in stock at PiHut this moment.

Silvester wrote:

Derek_Stewart wrote:I have a PI Zero 2 ready to be fitted as Pi3A is very rare.

If you act quickly they have some in stock at PiHut this moment.

Too late all out of stock, I have a spare Pi3b, just need to remove the USB connectors...

Derek_Stewart wrote:Too late all out of stock, I have a spare Pi3b, just need to remove the USB connectors...

No, they are still available, point your browser at : https://thepihut.com/products/raspberry ... del-a-plus

I've been looking out for one for a PiStorm I bought a month ago, so I was happy I got a 3A+ last night. I was considering removing USB connector or using GPIO riser on an old 3B+ but wasn't too happy about the extra 40% power it uses from Amiga. I also considered using a Zero2 but it is only 1GHz vs 1.4GHz