Issue 8 discussions...

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Dave
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Re: Issue 8 discussions...

Postby Dave » Thu May 02, 2019 11:45 pm

Peter wrote:
Dave wrote:The other part is that although this board will cost 4-5x more than the Q68 to produce (it's huge and has a LOT of parts - very Old Tech) I want the price on it to be much lower.

I think Dave made a cost estimate what the Q68 would take him to produce. Dave is a parts purchasing expert with a lot of experience, connections, and even the possibility to resell parts in case he later won't need all of them. Also, Dave can do SMD production himself. Both is of course much cheaper than production in small batches with help of reliable commercial services.

The Q68 comes at a price of £150.00 which I remember similar to comparable retro-computing boards, although the Q68 sells in much lower quantities due to being QL-specific and QL-optimized, and has ethernet on board. The price was not my decision, but I seriously think the Q68 is at the lowest limit, compared to the risk and workload Derek has shouldered - purely as support for the QL community. Thank you very much Derek, and please do not feel like the Q68 costs too much.


Hehe...

My guess of the cost for Issue 8 does not include the cost of parts I have had on hand for so long I no longer have a record of their cost - so about 40% of the parts on the Issue 8 are mathematically "free." I don't think the Q68 can be made by Derek for anything even close to £25. I think with the way Derek sources parts and has contract assembly, I'd be surprised if the Q68 cost less than £100 to make, and that's before any inspection, programming, testing, packaging.

£150 for the Q68 is a very fair price - especially considering it is made in very small batches and should be considered "bespoke custom hardware" for QLers.

I come from a slightly different background. I am used to making 500 or 1,000 of an item, and usually much simpler items. I have established relationships with suppliers, and I have 6 suppliers I "trust" (as in, yes, I'll order from them but still verify the parts meet the specifications and are genuine parts, not cheap knock-offs.) I understand Derek has subcontracted that responsibility to his contract manufacturer. It can't be expressed enough how valuable those relationships are, and they cost accordingly. It's the difference between a 1-2% failure rate and a 20-40% failure rate on the finished product.

So yes, with the "free" parts I have on hand, and the additional costs involved, I probably could make a few Q68s for £25, but once I started having to buy parts it would be dramatically more ;)

Also... I often buy thousands of a component I will use a few hundred of, knowing I can resell the surplus for a small margin and subsidise my project a little. I often buy components just to fill a cart to the "free shipping" level - which is why my cost basis on 68EC030s currently stands at $0.91/piece!

Also, if you do not have a Q68, you should contact Derek and buy one immediately. As orders slow, it will be harder and harder to justify the economics and sheer time involved in making a batch so the time when Derek will no longer make them is on the horizon. They're great value.


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Re: Issue 8 discussions...

Postby Dave » Thu May 02, 2019 11:46 pm

Cristian wrote:
Peter wrote:Thank you very much Derek, and please do not feel like the Q68 costs too much.

Let's proceed with caution: I don't think Dave was meaning this.
In any case, I'm sure all of us recognize the full worth of Derek's efforts.


Indeed. The Q68 is quite cheap for what it is.

I was only expressing that it affects my pricing flexibility because I can't really charge more for a lesser machine even if it has 5x the production cost.


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Re: Issue 8 discussions...

Postby Dave » Thu May 02, 2019 11:51 pm

Silvester wrote:What device are you going to use, where in I/O area is it going to be addressed? (rough schematic)

What machine are you expecting to use it on - BBQL ? (max baud?). I wrote a driver for MIDI on TC QL with definable queues - it kept up easily with two ports at 31250 doing MIDI bulk dumps. Be interesting to see how BBQL would deal with Q40 sending at 115200.

To write a quick SER driver to have something to play immediately with would be quite straightforward, but long term it would best to match SMSQ/E drivers/SBASIC interface (STX etc).


The SC28L92. Datasheet here:

https://www.nxp.com/docs/en/data-sheet/SC28L92.pdf

I would release a low cost BBQL card with it, and then be able to incorporate it into future designs. If a driver magically appear, the hardware will be open source, clearly documented, and well supported. It is similar to the 68681 but has functional hardware handshaking, 16-byte FIFOs, 68K bus friendly control signals and interrupt or polling capability. It is pin compatible with the 68681 too. It works up to 1mbps.

Thanks for expressing interest, Silvester.


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Re: Issue 8 discussions...

Postby Dave » Fri May 03, 2019 12:02 am

dden wrote:I am following this thread with interest. Do you mind telling us how many Q68s have been sold, and the batch quantities they are made in?

This may give Dave an idea of how many Issue 8 boards to produce.


Derek won't say, and he's right to do so. I have followed his thread and I believe he has sold somewhere between 65 and 85 based on public statements. This is a guess, so should not impact him at all. He's welcome to not correct me but it is pure conjecture on my part.

I am not so shy. Each Issue 8 will have a serial number. I'm feeling optimistic so serial numbers will be D18-XXXXXX. Cos tradition. :D

I will make small orders of PCBs until the design is verified, but then I will order 100 PCBs, because it is the most expensive component and hitting 100 gives the best benefit. I will assemble them in smaller amounts, so the components are only committed if they're likely to be sold in the next month or two.

I will auction off the first prototype, as in 35 more years it might be quite collectible. Or not. Who knows?!


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Re: Issue 8 discussions...

Postby Derek_Stewart » Fri May 03, 2019 12:37 pm

Hi Dave,

I would think it is very unprofessional to disclose customer information.

I put a serial number on the Q68 PCB and Case, which had the model number, batch number and unit number. So I find your comments on this silly.

I hope you can sell 100s of boards, I took a cautious approach to Q68 sales, as with past experience and hostile Press, I did not think there would many Q68 sales. But there is no one to constantly undermind the the Q68 process, as with other ventures I have undertook in the past.So sales were more than expected.

The advice form the people who make the Raspberry PI Board, that I would need to increase sales to over 1000 units and have a team of sales and market people to push the Q68 into the market. So they were not interested in manacturing the Q68 in Wales.

For one person is manufacture the PCB, construct the PCB, build it into a case, manage the sales and shipping around the world, provide an up to date software packag, give technicl support and think about advertising. Is a hard job, please this in mind with your proposed products. Manufacture is only only a small part of the product development process.

And bybtge way the Q68 has not been advertised for sale yet.


Regards,

Derek
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Re: Issue 8 discussions...

Postby Dave » Fri May 03, 2019 6:46 pm

Obviously it's not cool to discuss your customers. Total sales are not individual customers.

I never expected my rough estimate that the Issue 8 parts cost would be 4-5x Q68 parts cost would cause so much discussion!

Ok, well, this isn't a Q68 thread. It's an Issue 8 thread. So, can we get back on topic? :D

I have retained the ability for the Issue 8 to use the SuperHermes in the 8049 slot. I've placed some SMD components beneath the area to the left of the 8049 - the ADM208EAR serial IC that replaces the MC1488 and MC1489, and a 7408 that on one gate recombines SER1 and SER2 RX and the other gates are used as a speaker amp. Nasta had the clever idea that I didn't believe until I tried it out - the left edge of the SuperHermes will rest on the top of the 8302. This adds a LOT of mechanical stability to the SuperHermes.

Finally, was anyone else taught in school that half a byte is a nybble? Not a nibble. A nybble?


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Re: Issue 8 discussions...

Postby Derek_Stewart » Fri May 03, 2019 8:17 pm

Okay, back on topic when is the Issue 8 board going be available.

Can the operation system be changed from the supplied system.

What I mean is in the future someone may write an update the QL system.

Will all QL software run on the the system.


Regards,

Derek
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Re: Issue 8 discussions...

Postby Dave » Fri May 03, 2019 9:28 pm

Derek_Stewart wrote:Okay, back on topic when is the Issue 8 board going be available.

Screen Shot 2019-05-03 at 3.18.25 PM.png

This is my self-imposed deadline. I hope to make it. July is a good bet unless something goes horribly wrong.

Derek_Stewart wrote:Can the operation system be changed from the supplied system.

Yes.

The Issue 8 has a ROM socket that will take two original QL ROMs, stacked. This ROM will also accept QL-SD. A second ROM socket can accept a 28-pin EPROM or a 32-pin EPROM or flash IC. This would allow quite large EPROMs, obviously.

I'll supply the machine with an EPROM burned with the image of the buyer's choosing, from the selection on Dilwyn's website. JS or Minerva in a variety of languages will be the common choices. SMSQ/E will also be supported on the machine, but not included in ROM - at least initially.

Derek_Stewart wrote:Will all QL software run on the the system.


Any software that will run on an Issue 7 QL will run on the Issue 8 without modification, if the clock isn't changed. If the CPU clock is changed, everything else should work except microdrives and QLNet - these will require altering the ROM image for timing for the new clock speed. We will have some standard speeds and will offer pre-edited QROM versions for common speeds. As the ROM is mirrored in RAM, if anyone wants to, they could port the SMSQ/E code to alter the timings of JS and Minerva, and edit the RAM copy of the OS to suit. That would likely get QLNET working, but since SMSQ/E doesn't have microdrive code I don't know if it will fix microdrives.

Changing the CPU speed may result in some expansions not working - results are not guaranteed. 1980s hardware may not enjoy being plugged into a sped up bus.

At original clock (S)GC will work, and will have a little extra speed too due to the elimination of video RAM contention.

Good questions. Thanks Derek!


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Re: Issue 8 discussions...

Postby NormanDunbar » Fri May 03, 2019 10:42 pm

Dave wrote:Finally, was anyone else taught in school that half a byte is a nybble? Not a nibble. A nybble?


Yes, back in college in 1982-83 I was taught that. I was on the National Computing Centre Threshold Scheme at the time. The correct spelling never looked right though.

Cheers,
Norm.


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Re: Issue 8 discussions...

Postby Dave » Sat May 04, 2019 1:14 am

Ok, not just me then. My teacher was Barbara Jaworski, who wrote the school books for the National Curriculum that was just being introduced. She marked people down for using nibble. A nibble of data was any arbitrary amount, but a nybble was always exactly 4 bits.



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