Guide to setting up A2090a with SCSI2SD

[Jope]

It was a little heart, not smaller than three. :-D You don't have to do anything to get DMA transfers, it will do it automatically.

Your steps seem to describe use with an A2090. That is indeed like that, but not applicable to any other hd controller.

The A2091 has a different setup procedure, you should use HDToolBox.

Oops... I'm getting old!

I found the A2091 pdf manual and will have to have a look focusing on HDToolBox...

Hey Jope,

I've just collected my SCSI2SD and now will go for my tries with A2091 asap.

I've found the HDToolBox related Chapter on the A2091 manual in order to achieve a preliminary overview: do you think the Drive Type will be detected automatically for SCSI2SD + 2GB SD or do I have to "Define New Drive Type" by input specific parameters?

Thank you in advance

Marco

[Jope]

You'll always have to define a new drive type.. The existing types are read from a file called drive definitions, which will not know about your new drive.

Originally Posted by Jope

You'll always have to define a new drive type.. The existing types are read from a file called drive definitions, which will not know about your new drive.

OK, thank you for putting me on the right direction anytime I get lost.

So I've googled a bit about the procedure.

First, I've found here that the V6.6 ROMs of my just purchased A2091 do not support HDDs greater than 1 Gb (while the V7 do): therefore I think I can't use default SCSI2SD 2GB config but should go for 2 disks max 1 Gb each.

Regarding how to make HDToolBox to match the SCSI2SD config, I've found this post, that is in German (and Google Translator does not help) and applies to A590 variant, but Pictures looks self-explanatory.

There, SCSI2SD config is set: "Enable Parity", "Enable SCSI2 Mode", then for the drive: Auto startsector, 512 bytes sector size, 1945600 sector count, 950 MB virtual drive size.

Corresponding parameters in defining New Drive Type by HDToolBox are: 1788 Cyls, 1 Head, 1088 Blocks-p-T, for a drive size of 949 MB (972128K): I guess, in my case, this should be made twice by creating a DH0 and a DH1, where DH0 is the autoboot drive.

I should do all this for installing WB 2.1 while the mentioned guide shows 1.3 screenshots.

Do all those numbers and settings sound accurate to you?

Thank you very much.

[sodapop]

Hi RodTurbo !

Thank you very much for your detailed explanations !
I have exactly the same configuration (A2000 + A2090a, and bought a SCSI2SD and 2 Gb MicroSD card a few days ago), and it will help me lot I think...

BTW, I was wondering if it was possible to set up the whole process under WinUAE, since it emulates the A2090a board, it would be much easier to install all the stuff that way rather than with a real Amiga 2000 and floppies...
I tried, but never succeeded...

[TommyE]

Originally Posted by RobTurbo

I've sorted it, ended up going a different route. The EPROMs that need patching are U50 (HI) and U51 (LO), I joined them together using winhex (unify bytewise), disassembled the resulting file using IRA (with -a so I can see what the code looks like in hex), found the code that needed modifying and copied it into a new file so I didn't have to search through code that I don't need, then changed it to what it should be, saved it then compiled it with vasm, now I know what the code I need looks like in hex so all I had to do was search the combined file to find the area that needed changing, then edited, saved, split back into two (dissect bytewise), then wrote the files back to EPROMs.

I didn't want to erase the EPROMs from the card (both 27c64) before I knew it worked, so I had a rake around and found a 27c512 on an old motherboard and a 27c256 in an ECU I don't need anymore so I copied the HI file 8 times and the LO file 4 times, wrote them, fitted them, changed the SCSI2SD settings so the last "drive" was 500mb, re-prepped RES5: with double the cylinders, restarted and formatted DH5:, all went well and I now have a fully functional 487mb "drive"

Now I know it works I'll erase the original EPROMs and write the new files to them, if anyone want's the patched files I don't mind sharing!! Now off to do some A2000 keyboard research...

Hello RodTurbo

Read your post with great interest, and wonder if you would share the ROM with me?

Regards
Tommy

[RobTurbo]

Originally Posted by sodapop

Hi RodTurbo !

Thank you very much for your detailed explanations !
I have exactly the same configuration (A2000 + A2090a, and bought a SCSI2SD and 2 Gb MicroSD card a few days ago), and it will help me lot I think...

BTW, I was wondering if it was possible to set up the whole process under WinUAE, since it emulates the A2090a board, it would be much easier to install all the stuff that way rather than with a real Amiga 2000 and floppies...
I tried, but never succeed...

I tried to set everything up in WinUAE, I think I managed to get it to work with a virtual drive but couldn't get it to work with the actual SD card, so it was no use really, I have a USB floppy emulator so I just put all the floppies I needed on that which made things a bit quicker.

Originally Posted by TommyE

Hello RodTurbo

Read your post with great interest, and wonder if you would share the ROM with me?

Regards
Tommy

I got your PM but for some reason it wouldn't let me reply, I've attached the patched files, I haven't been around anything Amiga for a while now so I'm rusty on the details, but write each file to the corresponding U50 and U51 EPROMs and the 256MB limit will have disappeared! Any existing HDD setup you have will still work without having to change anything else, enjoy!

[McTrinsic]

Setup with WinUAE could only work with an SCSI2SD v6. Up to v5 the (simulated) drive geometry is stored in the SCSI2SD.

The v6 does that also but could be used as a USB drive.

Cheers,
McT

[sodapop]

@RobTurbo : Thank you for the answer... I gave up the installation process under WinUAE... too much pain trying to figure out the custom software from Commodore for the A2090a. And I didn't manage to get it work inside a real Amiga 2000 neither...
Really fed up with the A2090a + SCSI2SD solution, I'm going with something else (CF device from Kipper2K) !
Thanks anyway for your tutorial !

[TommyE]

Originally Posted by RobTurbo

I tried to set everything up in WinUAE, I think I managed to get it to work with a virtual drive but couldn't get it to work with the actual SD card, so it was no use really, I have a USB floppy emulator so I just put all the floppies I needed on that which made things a bit quicker.



I got your PM but for some reason it wouldn't let me reply, I've attached the patched files, I haven't been around anything Amiga for a while now so I'm rusty on the details, but write each file to the corresponding U50 and U51 EPROMs and the 256MB limit will have disappeared! Any existing HDD setup you have will still work without having to change anything else, enjoy!

Great, thank you for the files.

I will do some burning and formatting.
Need to get a scsi2sd

Regards
Tommy

[indigolemon]

Timing is everything, amazing that this thread has appeared at the top of the hardware section the day after I finally got round to digging out my Amiga2000! Happily it's very much alive, and the battery - while starting to leak, hasn't done any damage (and is now in the bin).

I too have the A2090A card inside my A2K, hooked up to a Miniscribe 8425 disk which is making the most horrendous noises and giving me read/write errors ( I must confess, I had never heard of the ST-506 standard till I looked it up last night )

So, thanks for the useful information! Looks like I'm on a mission to find either a SCSI HDD or a SCSI2SD myself.

@TommyE - if you are able to burn the relevant EPROMs, would you be willing to burn a second set I could purchase from you? No worries if not, just thinking my chances of finding a suitable drive under 256MB are rather slim

[TommyE]

Originally Posted by indigolemon

Timing is everything, amazing that this thread has appeared at the top of the hardware section the day after I finally got round to digging out my Amiga2000! Happily it's very much alive, and the battery - while starting to leak, hasn't done any damage (and is now in the bin).

I too have the A2090A card inside my A2K, hooked up to a Miniscribe 8425 disk which is making the most horrendous noises and giving me read/write errors ( I must confess, I had never heard of the ST-506 standard till I looked it up last night )

So, thanks for the useful information! Looks like I'm on a mission to find either a SCSI HDD or a SCSI2SD myself.

@TommyE - if you are able to burn the relevant EPROMs, would you be willing to burn a second set I could purchase from you? No worries if not, just thinking my chances of finding a suitable drive under 256MB are rather slim

No problems, I can burn a set for you.

I also have the same drive as you, and mine is also reporting read/write errors from time to time.

I think I will see if I can afford a SD2SCSI card, but been using too much money on other Commodore stuff lately

Will keep you posted..


Tommy

[indigolemon]

Originally Posted by TommyE

No problems, I can burn a set for you.

I also have the same drive as you, and mine is also reporting read/write errors from time to time.

I think I will see if I can afford a SD2SCSI card, but been using too much money on other Commodore stuff lately

Will keep you posted..


Tommy

Thank you, that's very much appreciated. Hopefully we both manage to get these machines booting normally again

[retrofriends]

I'm going to bump this thread back to life...

RobTurbo and others, I thank you for the valuable information you provided on the A2090a. I was able to successfully get this combo to work thanks to you. A link to this thread is just about the first thing to pop up when googling "A2090a SCSI2SD". I decided to turn the camera on and film the procedure, along with a repair of my A2090a. It's on YouTube now:

[ Show youtube player ]

I gave credit in the YouTube description to this thread, in case someone gets to my video first.

[sodapop]

@retrofriends :

Thank you very much for these videos and for the hard work ! Much appreciated !
I didn't take the time to test the procedure so far (I'm at work during the festive period), but I will give it a go ASAP !

Cheers !

[BobNS]

Originally Posted by Arnie

The bit that I don't understand is, if you have mounted the drives RES*:, how can you format drive DH*:?

What are the pro's & cons of mounting 4 drives vs creating 4 partitions?

Hello,
I have almost the similar "don't know how". I read 2090 "Anleitung" (german) where is says that for each SCSI disk (after first is setup) you need to have two entries in MountList. One is RESx (desribed as here) and for each RESx you need to have DHx, where DHx is similiar to RES entries except that buffers are 30 and LowCyl is 2 and HighCyl is something like 1023. I tried following the "Anleitung" but with no success. When I modified RESx to have Reserved 2, LowCyl 0 and HighCyl 1023 things start to work: mount RESx, prep RESx, reboot, format RESx and now I have 3 additional 256MB drives with trashcan inside. Maybe this will help somebody with 2090A after initial setup? I am not sure if this is ok but if I follow things, Amiga mounts RESx and DHx and then when I want to format DHX it just says: Disk is empty, can't do format (or something similar even if it mount it).

[Jope]

RESx: should not be that large! It is only there for the drive's header info.

DHx: will be automatically mounted by the 2090 driver, and any other partitions on that drive will have to be mounted manually.

You are supposed to run prep after mounting RESx: in order to create the header info for the drive and also define the size of DHx:. RESx: is not intended to be formatted with the format command. DHx: is supposed to be formatted, after it is automounted.

In normal use, RESx: is never mounted. Only DHx: is visible, and any other partitions you create/mount manually. RESx: is used only when prepping.

What kind of geometry did you specify for RESx: and when doing prep? The 2090 can't handle very large disk sizes without a patch. There is also a max limit to the amount of heads you can specify, you should keep it somewhat sane. Limit to maybe four heads! SCSI operates with logical block addresses, but a geometry is still needed for the benefit of the OS and hddisk driver.