premised:
The chip KR1818VG93 is pin compatible with VL1772 ??
The first is the FD Controller of the betadisk, the second is for Disciple, +D, SAMCoupe.
In affirmative case could be intersting to implement also this standard much use in England and Italy.
A most interesting document created from the Ramsoft is available:
http://www.ramsoft.bbk.org/tech.html

The KR1818VG93 chip (FDD controller) is fully compatible with WD1793 chip.


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PETERS PLUS LTD

Therefore it is impossible to implement the MGT disk system??

May be. Now we continue to search technical description of VL1772 chip. It's a pity your link not include this info.

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PETERS PLUS LTD

I saw your link more attentively and found there technical information about the VL1772. Thank you.
And I have info about compatibility WD1793 and VL1793. It's not surprise, certainly.
So, VL1772 is "almost compatible" with VL1793. It need the test, certainly. May be we will have result during one hour.
But I have a question to all: is MGT Disk System so popular?

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PETERS PLUS LTD

There's also a equivalent IC of the VL1772: the WD1772...
If you search with this string in the search engines in Internet
you find many more information..

It's very popular in the UK and also in the Italy.
Unfortunately the Spectrum has not had a disk interface supported directly from the Sinclair.
This to allowed that many producers developed other interfaces with priority standards.
The standard that has had more spread has been the
MGT exactly. Fist with disciple (a fantastic add on with also
Printer Interface, NetworkInterface, 2 joystick port, snapshot button..) and after with the +D a version with only FDD , parallel port and snapshot finally the MGT has made a fantastic Speccy clone the SAM Coupe with the usual filesystem.
Another disc interface popular is the Opus Discovery.
In order to make a comparison in the western market
the betadisk it has had a smaller sale of the two mentioned.
To confirmation of said how much you can see the UK Spectrum emulator that supports MGT.

We have the first results of comparisons of technical info of VL1772 and Sprinter's FDC chip (WD1793).
In Sprinter computer FDC is accessible during work of TR-DOS and OS Estex.
Some of our FDC ports, which used in MGT Disk System, are busy.
For example, in MGT Disk System 1Bh port: input - FDC status; output - FDC command. Sprinter CPU use 1Bh port as internal keyboard port. And we have same situation with some other ports.
Does anyone have any ideas?

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PETERS PLUS LTD

This message is of my speccy friend Bodrato Stefano:
I don't see many chances:
=================================================
- To patch the MGT ROM so that it keeps the same hook code and ROM location entries but uses other ports.
- To switch the 1Bh (and others) port mapping depending on which ROM page (or ROM location) is used.

Stefano
=================================================

So, we have one variant: patching the MGT ROM, isn't it?
Who is able to do it better?

And we still wait other opinions about MGT DS.

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PETERS PLUS LTD

MGT DOS is in my opinion the best one. I use a patched version which allows to change drive very fast (LOAD d1 or LOAD d2), and the directory is cleaner and better readable than on TRD. It will be great if it could be possible to replace the TRD emulation with MGT.