HD 20MB Dobbertin CPC Hard disc

[Cpcmaniaco]

Hello all.


Thanks to Jose Leandro, now we have all the layout of this hard disc for CPC.


You can see on the Jose Leandro web :


HD - Interface Dobbertin Industrie AMSTRAD CPC


And I put too on the CPCwiki :


Dobbertin Harddisc - CPCWiki


@Gryzor can you see a little problem with 1 file I try to upload : Interface PCB Layout.png


If you can't fix, then I change the file from .png to .jpg and try to upload another time.


On the web of Jose Leandro is the file too.


Perhaps now someone can make a new test with this new information, makes clones, and do more actual things, because now is dificault to get this old hard disc of 20 MB, and the ISA controller.


Enjoy it.

[Gryzor]

Hey mate, can you give me the filename on Jose's page, if you took the image from there? Not sure which one you're talking about...

[TFM]

Great work CPCManiaco! Thanks for posting!


Would be awesome if we could get clones of this awesome device!

[GeoffB17]

Interesting.

This looks to be pretty similar to the old 'Hard Cards' we used to have, way back.

The early PCs I used came without any HD.   This includes the first Amstrad PC 512 and 640 machines, and we were adding a 20 Mb Hard Card in there.   I seem to remember that there was a removable cover on part of the case that exposed the ISA slots, so you didn't need to remove the whole case for the Amstrads - had to for various other brands, incl some early Commodore PCs (which came with a VERY nice keyboard - still using one now!!).

You just inserted the HC, turned on the machine, and it saw the HC, which then needed formatting etc in the usual way.

Quite handy for me.   I had a succession of 'borrowed' office machines at home.   the HC though was mine.   Whenever I had to return a PC, I just took the HC out, then when I got another computer, the HC went back into that!!

Some time later, the PC's started coming with the HD already installed!!!

So, I'd look for specs of the old Hard Cards, and check the details of them against the details of the device detailed in this thread?   May be very similar??

Geoff

[TFM]

The big advantage of the HD20 is that it literally works with ALL CPC OS (except Symbos), you can even start the majority of games from it. Dobbertin made an awesome integration for AmsDOS and both CP/M. Unter CP/M it's even more quick than the RAM disc. 

[arnoldemu]

I think it would not be worth it to re-create the hardware there is too much and it relies on old hard drive technology.

I think it's too old and restricted. XD-DOS is very good, it would be better to patch it for X-MASS. But ACMEDOS looks like it's better than XD-DOS?

[TFM]

I totally disagree. Where is it restricted? If you fill up 20 MB on CPC with software you are actually using at least once in every three months then ok. But you won't even make it up to 5 MB. I guarantee that!

And who told to use original parts? Put it all in an FPGA if you like and instead of an old 20 MB hard-disc you can connect Flash, DOM, current HD, USB or what ever you can get for cheap (and is reliable).

Nothing can beat X-DDOS today - still! About the other mentioned solutions... ACMEDOS is not there yet, and it does not patch CP/M. Also it has to show how much games will run with it. I don't want to talk bad about it, but to do a FAT system is by far more RAM consuming than a DOS imho.

I think it would be a gorgeous thing to bring back the HD20 to life again - in which physical form ever.    [nb]And I'm tired of people telling me what I can't do.[/nb]

[gerald]

And who told to use original parts? Put it all in an FPGA if you like and instead of an old 20 MB hard-disc you can connect Flash, DOM, current HD, USB or what ever you can get for cheap (and is reliable).

Nothing can beat X-DDOS today - still! About the other mentioned solutions... ACMEDOS is not there yet, and it does not patch CP/M. Also it has to show how much games will run with it. I don't want to talk bad about it, but to do a FAT system is by far more RAM consuming than a DOS imho.

FPGA is not a magic item you throw to replicate an old HW 
We still miss the most important thing here : the schematic of the controller board.

From the picture, it also have microcontroller and dedicated ROM.

The only thing we have on the wiki page is the interface card that only do address decoding to the ISA card.


Patching the ROM for XMEM/Symbiface would be easier.

I think it would be a gorgeous thing to bring back the HD20 to life again - in which physical form ever.    [nb]And I'm tired of people telling me what I can't do.[/nb]

So you know what you have to do. I'll take one for sure if you make them.

[Kris]

I just have a look at those pages http://hardware.speccy.org/temp/
What an awesome amount of work, very interesting, well detailled and all needed informations are supplied !


Great job !

[Bryce]

Well it's not quite enough info to get a HD connected (as gerald mentioned above), but it is enough to make a CPC ISA slot.

Bryce.

[arnoldemu]

I totally disagree. Where is it restricted? If you fill up 20 MB on CPC with software you are actually using at least once in every three months then ok. But you won't even make it up to 5 MB. I guarantee that!

The hardware is too old and slow. Better to patch XD-DOS for new hardware.
To recreate the hardware accurately you need an old PC HD interface.

[TFM]

The hardware is too old and slow. Better to patch XD-DOS for new hardware.
To recreate the hardware accurately you need an old PC HD interface.

Too old? Not as old as the CPC!
Too slow? If 80 KB/s is too slow then stop using floppy discs!!! Ok, only SF2 left for you currently.

Sorry, maybe the Amiga would fit your needs more than the CPC.


@Gerald : The ST 11M Segate controller is standard, not a problem.

[gerald]

The ST 11M Segate controller is standard, not a problem.

Standard, but not that widely available. Not even talking about compatible (and working) MFM drives.
You also have to sort the enclosure(s).
I am not conviced that making clones is worthwhile.

Also, is the associated ROM capable of dealing with more than 20MB ?

[TFM]

You're guessing. I analyzed the controller. It's a standard XT controller for MFM discs. It has its maximum higher than 20 MB, but of course it's XT technology.


Now let's not get lost in details here. I point in cloning the HD20 is the fact that we have awesome software for it. Nothing beats X-DDOS to the current day (as long as we stay with Amsdos and CP/M as OS).

[Bryce]

Yes, but the CPC is repairable silicon/PCB, an MFM drive is a mechanical, unrepairable part. There's a few on ebay at silly prices, but their reliability would be extremely questionable. No matter how good X-DDOS might have been, it's pointless building hardware for an expensive, unreliable media.

Bryce.

[TFM]

Yes, but the CPC is repairable silicon/PCB, an MFM drive is a mechanical, unrepairable part. There's a few on ebay at silly prices, but their reliability would be extremely questionable. No matter how good X-DDOS might have been, it's pointless building hardware for an expensive, unreliable media.

Bryce.

Are you kidding? I got two MFM drives, both run very well since about 28 years. Now show my your modern-day-drive working so well for so long. Todays crap is usually dead after 5 years. In addition fixing parts on a PCB of an MFM drives is not much more hard that fixing stuff on a CPC PCB, even I could fix a problem on a Vortex Winchester drive (which worked 25 years flawless).

As I pointed out before I'm not suggesting to do a true 1:1 clone (which would of course be nice). But the real deal would be to have a interface for a cheap todays DOM or what ever which is HARDWARE COMPATIBLE to the Dobbertin HD20. Gerald is #1 on the waiting list, you can be #2 if you like.