Gosh Wonderful Revisited

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Geoff Wearmouth

Aug 11, 2014, 8:14:54 PM8/11/14
People often ask me. "Geoff: That Gosh Wonderful ROM - is it really so wonderful?".

Yes it is. Considerable thought went into it. It is just a tribute ROM and no more. In 1984, the ROM author, explaining the Integer -65536 feature, said that nothing could be done about it now. Well thirty years later people are still begging to differ. The original was so near perfect that it is exhilarating to use a machine in flawless balance.

The other bonus is that it is completely compatible with hardware peripherals either real or emulated. It will drive the ZX Printer and those printers - Alphacom 32, Timex 2040, Seikosh GP50S that sniff the ROM.

It is also compatible with both versions of the ZX Interface 1, including network, RS232 and Microdrives. Real or emulated.
It works flawlessly with the Miles Gordon technology DISCIPLE Disk Interface and Plus 'D' Interfaces.

Above all it is compatible with commercial software, your type-ins and well-written assembly language programs.

All the entry points named in the Melbourne House books are maintained though in some cases the actual addresses were wrong and these are corrected.

All the special, non-standard entry points used by Interface 1 and Miles Gordon Technology are maintained so that these Interfaces works as well.

Above all it's fun and stable. Just what it was supposed to be. Use the original editor if that's your preference or type one letter at a time, like the Jupiter Ace and most computers since.

Classic BASIC features like Renumber and Delete have been adapted from my routines in Outlet Magazine and 1980s PD libraries and I've implemented a simple version of Andy Pennells' Stream Lister so that Microdrive streams appear with letter 'M' and Plus 'D' with the letter 'D'.

Full updated details of the Gosh Wonderful ROM are here and you can see the Assembly Listing and download the ROM from there too.


Geoff Wearmouth

Volker Bartheld

Aug 13, 2014, 6:28:07 AM8/13/14
Hi Geoff!

On Mon, 11 Aug 2014 17:14:54 -0700 (PDT), Geoff Wearmouth wrote:
> People often ask me. "Geoff: That Gosh Wonderful ROM - is it really so
> wonderful?". Yes it is.

Second that. It is really heartwarming to see, that an old hardware
platform such as the Sinclair ZX Spectrum still has a very active fan

Some time ago, I fired up my Issue 2 Speccy (bank switched, external case,
keyboard, power supply, regulator, composite-out mod and whatnot), still
ran like a charm. OK, the inevitable color issues - no biggie. Even the
IF1 (first ROM revision) and microdrives didn't have defects. After
replacing some cartridge felted foam pads (dual side adhesive foam tape
did the trick), even external storage was online again.

However: Due to the dreaded print-through issues, none of the cartridges
was readable without errors. So I wrote a tool for RAW sector extraction
and PC interfac (beta stage, available for download at
ftp://ftp.worldofspectrum.org/pub/sinclair/tools/pc/mdv2img.zip) that
confirmed the problem.

Perhaps some data recovery expert can help and recombine the raw sector
image (redundant passes possible) with existing HDCHK (header checksum
error), DESCHK (record descriptor checksum error - that's what links
sectors together) and DCHK (data checksum error - e. g. corrupt sector
payload data) to something that actually works.

However, I doubt that this will succeed with the current Microdrive
hardware. Why? The ULA2G007 has an x200/x8 amplifier and Schmitt trigger
already built-in (see http://www.1000bit.it/support/manuali/sinclair/ql/SINCLAIR%20QL%20SERVICE%20MANUAL.pdf,
page 63, diagram D9 - this is the QL service manual, but that doesn't
matter much, since the QL has the same Microdrives that you could connect
to the Speccy - via the IF-1, that is).

The problem is the Schmitt trigger. It will work well with clean signals,
but in our case the signal consists of two (or more) overlayed rather
sinusodial signals having about 1:2-1:5 amplitude ratio and varying phase
(not uncommon with print-through phenomena). In that environment, the A/D
conversion process fails miserably. And there's no chance getting around
that (e. g. by tweaking an amp, adding noise suppression stuff) since
everything is "hardcoded" in the ULA.

That said: Thanks for sharing your efforts with the community. Much
appreciated. Keep up the good work!


@: I N F O at B A R T H E L D dot N E T
3W: www.bartheld.net
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Geoff Wearmouth

Aug 25, 2014, 2:12:42 AM8/25/14
I still use your VBSpec emulator from those days.
Your project to create a corrected electronic version of the Complete Spectrum ROM Disassembly was the high point of this group.
Since you like my ROM, I have created an animated gif that shows off its extra features on my phone

Gosh Wonderful


Geoff Wearmouth

Aug 26, 2014, 9:31:10 PM8/26/14

I am pleased that your first version Interface 1 still works. I haven't had my hands on one.
The Gosh Wonderful ROM is fully compatible with Interface 1 and also fully compatible with the Plus D and the Miles Gordon Disciple Disk Interface.

It can enhance the experience as this gif demonstrates


Geoff Wearmouth

Volker Bartheld

Aug 27, 2014, 8:53:52 AM8/27/14
Hi Geoff!

On Tue, 26 Aug 2014 18:31:10 -0700 (PDT), Geoff Wearmouth wrote:
> I am pleased that your first version Interface 1 still works. I haven't
> had my hands on one. The Gosh Wonderful ROM is fully compatible with
> Interface 1 and also fully compatible with the Plus D and the Miles
> Gordon Disciple Disk Interface. It can enhance the experience as this
> gif demonstrates
> http://www.wearmouth.demon.co.uk/plusd.gif

Extraordinary! I wish, I could have afforded the MGT Plus D back then.
That way, I probably wouldn't have lost my data due to magnetic print
through as it was the case with the IF1/MDV combo. After rebuilding the
felted foam pads, my cartridges are as good as new - from a mechanical
perspective. Just a simple reformat necessary and you're good to go.

However, I wasn't able to extract the data from them, at least not just
using mdv2img [1] and without external devices that directly capture the
signals from the stereo head (=a very time consuming and experimental


[1] ftp://ftp.worldofspectrum.org/pub/sinclair/tools/pc/mdv2img.zip

Julien Berthel

Mar 1, 2021, 10:44:23 AMMar 1
Hi Geoff,
I hope you are ok ?

This link http://www.wearmouth.demon.co.uk doesn't work !
Have you a new link ?

Best Regards Julien

Julien Berthel

Mar 1, 2021, 10:45:03 AMMar 1
Le mardi 12 août 2014 à 02:14:54 UTC+2, Geoff Wearmouth a écrit :

Geoff Wearmouth

Mar 1, 2021, 7:34:57 PMMar 1
Hi Julien,

I am doing fine and inhabit Twitter with my real name these days.
Demon sent the bailiffs round but most of the site is on the Wayback machine.
The Gosh Wonderful ROM evolved into the Looking Glass ROM which is much purer with the same two modes and context sensitive help screens. In the enhanced mode it uses the Jupiter Ace keyboard layout and is strictly one letter at a time. Both ROMs are bundled with the ZX Spectrum Next distribution which can be downloaded from specnext.com whether you have a Next or not.

Bonne chance,


Message has been deleted

Julien Berthel

Mar 3, 2021, 1:44:35 PMMar 3
Thanks Geoff,

Unfortunately, I don't have a Next yet.

I found in the repository of ZX Spectrum Next computer the latest GW ROM (https://gitlab.com/thesmog358/tbblue/-/tree/master/src/asm/gw03v33).
But there isn't lg18v07.asm, is-it normal?

Julien <JOK>(: betrayed by my French accent :)</JOK>

Colin Piggot

Apr 12, 2021, 1:12:34 PMApr 12
In case it's of interest/use to anyone, I revisited the failed format of Sinclair's ZX ROM Cartridges over the last two years, releasing an Interface 2 style cartridge port suitable for any model of the ZX Spectrum; 16k,48k,+,128k,+2,+3,+2a/b and even the Next. Coupled with a flash memory cartridge I also released which allows 16 different ROMs to be selected, this would allow you to use Geoff's GW & Looking Glass ROMs on ZX Spectrum hardware without having to open them up and replace the original ROM chip. (You would need an EPROM programmer to write to the flash chip to store the ROM images you want to use)

Info on these interfaces are on my site at: https://www.samcoupe.com/
and eBay: https://www.ebay.co.uk/sch/quazar-sam-coupe-sales/m.html

Colin Piggot

Apr 12, 2021, 1:16:21 PMApr 12
Just to add, if you've already got an Interface 2 or one of the other early interfaces with a cartridge port such as the Kempston Pro or RAM Turbo, then the flash memory cartridge I make will also work with them.
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