Prototype TVC Sprite module
The page say it is developed in UK. And planned the final version with custom IC-s, but this is never happened.
Bruce, do you know anything about it?

The wired Enterprise prototypes looked similar?

Very interesting...I do not know anything about it! It is possible the IS hardware engineers developed it but I was not involved and do not recall seeing it. By then though hardware was in the basement and software upstairs, all in quite a large building, so it is possible.

But yes, the Enterprise wire-wrapped prototypes looked similar to this (but with even more wires! )

Can you remember which floppy drives used for the EXDOS developing?
It is a lot of different models?

Ok, you can't remember about the model numbers but can you remember how these drives looked out?
3.5 or 5.25, full or half height? If 5.25 then a older "central lock" mechanism drive, or later with turnable lock arm?
If 3.5 then with a big eject button, or a smaller (like as the modern drives)? Button have a any color?

No, not the exact makes/models! It was a mixture of 5.25" and 3.25", 40 track and 80 track. 3.25" were fairly new on the market - it was the first time I has seen one. I think they were full height with the big eject button. Sorry I did not pay too much attention to the colour or 5.25" door catch! 

The EXDOS manual have a list of tested drives (8 3.5", 3 5.25"), these tested at the IS? Or in IS used only few drives, and others tested by the Enterprise company?

I would say we had fewer 3.5" drives than that for s/w development so someone else must have done more compatibility testing, but the list probably includes the drives we developed with. I would think it was Enterprise Computers but I can't actually recall - if IS had the drives they would have ended up with s/w development!

Why I ask it: previously we talked about the EXDOS Disk Change detection, you noted the EXDOS not works fast as possible probably because the hw Disk Change detection not used. Then I answered yes, it is disabled by default, and can be enabled if all drive use compatible method. But nobody know which drives compatible...

I would think all later 3.5" drives have it - even 30 years ago most did but we did have at least one that did not support it. But there may have been some confusion later with a minor change in cable pinout? Or was that when HD disks were introduced? I can't quite remember.   I don't think it is possible to detect whether a drive supports it from s/w  which is why it is disabled by default (safe option).

If you DIR you will see a small pause before the number of free bytes is displayed. If you DIR a second time the pause will not be there if the disk change signal is working and enabled (provided you have enough buffers for the FATs to be in memory, presumably!).

Not a 3.5" ?
3.25" also existed!
Teac FD-35?
(Attachment Link)
Two version (360K/720K) are in the EXDOS manual list.
When the PC/AT introduced, then changed the pinout, then went the Disk Change from pin2 to pin34.

But the EXDOS have a another signal: at pin1 Disk Change Reset
Very strange because signal at odd pin! (these are usaly GND) And about the 99.9999999...% of the drives not have this signal.
I started the investigation about this signal.
Then found the idea of this signal come from the original Sony Microfloppy drive.
But it is have a different (26pin) cable pinout. (And as we talked previously: it is 600rpm drive, can't used with standard EXDOS card and 4Mhz Z80)

At this page found something from a Sony drive with 34pin interface, and it is have a Disk Change Reset at pin1. (these Sony drives also have a big eject button)

Only one non Sony drive found with this signal, Panasonic JU-363

The EXDOS manual say only the Sony MPX-026R compatible with hw disk change checking of the EXDOS.
But unfortunately not found anything about this drive, the Google only found it in the EXDOS manual...

Yes 3.5!  I don't recall anything to do with the reset signal  but I did not write the low-level disk driver so did not have much to do with the disk change signal at all really. If there is no reset signal, how does the disk changed indicator get reset again?

The EXDOS manual say only the Sony MPX-026R compatible with hw disk change checking of the EXDOS.

Have you ever seen one? If the EXDOS manual is the ONLY place that google finds that model number, I wonder if it is a mistake in the EXDOS manual?!

I tried to playing with letters (for example MPF instead MPX) but not found anything similar

Me too! 

But I think the Monsterprise would be a better name

At the time the membrane keyboard always seemed to be a source of criticism for the Enterprise not having a "proper" keyboard like some competitors. Personally I think it is ok, but I cannot touch type. But then how many home computer users could?

has anybody information (or even ROM images?) about the software of the "Monsterprise" ...?

I certainly haven't; I hadn't even heard of it until zozo told me about it on this wonderful forum 

I never understand this, because as I know, most of the keyboards uses the membrane technology, and not in the past but now too. The problem is the quality I think: EP has bad quality membranes...?

Yes I agree, and membrane technology has improved too. But at the time there was the IBM PC which had an excellent keyboard and the BBC micro etc which had pretty good keyboards. The Enterprise keyboard feels a bit "rough" in comparison as you press a key - I think it's not so much the membrane but the way the keys are held in place. On the other hand there was the Spectrum...