QLUB Adapter - Initial Release...

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gbejniet
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Re: QLUB Adapter - Initial Release...

Post by gbejniet »

Someone correct me if they actually know whereof they speak unlike me - but I am assuming that a Spectrum emulator running on a QL would not be able to reproduce the timings in software to bit-bang the network protocol accurately - so any IF1 emulation would be bound to the QL's implementation and its timings dependent on that.

In which case, my experience & Martyn's advice is that AH ROM QLs match IF1 timings more closely than other ROM versions and I've found them to be more-or-less compatible and error-free in both directions.


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tofro
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Re: QLUB Adapter - Initial Release...

Post by tofro »

gbejniet wrote: Wed Feb 22, 2023 11:44 am Someone correct me if they actually know whereof they speak unlike me - but I am assuming that a Spectrum emulator running on a QL would not be able to reproduce the timings in software to bit-bang the network protocol accurately - so any IF1 emulation would be bound to the QL's implementation and its timings dependent on that.

In which case, my experience & Martyn's advice is that AH ROM QLs match IF1 timings more closely than other ROM versions and I've found them to be more-or-less compatible and error-free in both directions.
I think you're underestimating the capabilities of the QL a bit - Especially considering you could run an emulator on a Gold or SuperGold card.
There are ZX Spectrum emulators that just-in-time compile Z80 code to 68000 code and run at up to 300% of Z80 speed on a GoldCard - these could relatively easily bit-bang the IF1 network protocol. There are also emulators that (nearly) completely emulate the ZX Interface 1 with Microdrive and serial port emulation. But actually none (at least to my knowledge) that would emulate the ZX network (probably the biggest reason for that was lack of demand). Technically, it should be possible on faster QLs or at least by off-loading the networking code to native 68000 machine code.


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Maskenlos
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Re: QLUB Adapter - Initial Release...

Post by Maskenlos »

There are also emulators that (nearly) completely emulate the ZX Interface 1 with Microdrive and serial port emulation.
There are really ZX Spectrum emulators for the QL that emulating the ZX Microdrive? In terms that you can put in a ZX Cartridge into the QL Microdrive and load from it?

Can you point me to a link?

Thanks,

Stephan


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dex
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Re: QLUB Adapter - Initial Release...

Post by dex »

Maskenlos wrote: Wed Feb 22, 2023 1:11 pmyou can put in a ZX Cartridge into the QL Microdrive and load from it?
Even without any emulator.
I have found sources for such routine (reading ZX Microdrive on the QL).


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tofro
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Re: QLUB Adapter - Initial Release...

Post by tofro »

Maskenlos wrote: Wed Feb 22, 2023 1:11 pm
There are also emulators that (nearly) completely emulate the ZX Interface 1 with Microdrive and serial port emulation.
There are really ZX Spectrum emulators for the QL that emulating the ZX Microdrive? In terms that you can put in a ZX Cartridge into the QL Microdrive and load from it?

Can you point me to a link?

Thanks,

Stephan
Check Dilwyn's page (whereelse?) for a number of surprisingly good ZX Spectrum emulators for the QL. There were quite a few.


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Peter
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Re: QLUB Adapter - Initial Release...

Post by Peter »

tofro wrote: Wed Feb 22, 2023 1:28 pm Check Dilwyn's page (whereelse?) [...]
Somewhere else actually. ;) That site will shut down in March and has moved here:
https://dilwyn.qlforum.co.uk/spectrum/index.html


Maskenlos
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Re: QLUB Adapter - Initial Release...

Post by Maskenlos »

I met Carlo around 1992 / 1993 at a QL meeting in the Netherlands, and I recall that MDV support was not possible:
(2) MICRODRIVE support

The MicroDrive subroutines and matching Hook codes of the ZX Interface 1
Shadow ROM are fully emulated. Nonetheless, it is not (yet) possible to read
ZX Spectrum microcartridges directly via the QL microdrives
. The files on
your Spectrum microcartridges must be transported to the QL in another way,
e.g. via the serial line (see next section).
Do not take me wrong, Spectator is a great emulator and I used it a lot during these times.

The short description of the other ZX emulators on Dilwyn site does not mention the keyword "Microdrive". I remember very well that I received a disc from a Russian QL - fellow with a tools allows to connect a tape player to the network port of the QL and load / import ZX Spectrum programs. Was rally a great achievement. Long time ago....

Best,

Stephan


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Re: QLUB Adapter - Initial Release...

Post by ones' complement »

Maskenlos wrote: Wed Feb 22, 2023 2:27 pm I met Carlo around 1992 / 1993 at a QL meeting in the Netherlands, and I recall that MDV support was not possible
AFAIK the problem wasn't software but hardware. The read/write frequency of the ZX and QL systems are different.


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tofro
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Re: QLUB Adapter - Initial Release...

Post by tofro »

I'm wondering if that really is a problem. A comment in the Minerva "read Microdrive" routine proudly claims it could cope with data rates that are 40% off - Which would perfectly cover IF1 timing (which is 20% off).

What we know is that the sector and header format is slightly different (checksums for both header and data block are words on the QL, and bytes on IF1-written tape). So, you would definitly need a new driver to pick apart the differences.

I'm pretty sure a QL would not be able to properly format and write a cartridge to be read by an IF1. But it could well be you could make it read a Spectrum-formatted tape.


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RalfR
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Re: QLUB Adapter - Initial Release...

Post by RalfR »

tofro wrote: Wed Feb 22, 2023 3:45 pmI'm pretty sure a QL would not be able to properly format and write a cartridge to be read by an IF1.
Perhaps this is possible, as Dave Walker has written drivers to read and write OPD cartridges on the QL. But I do not know, if they are similar to the QL-


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