Help with External Drives please, and booting Externally from MOS

[soydemadrid]

Hi everyone - I have a Tatung Einstein 256 and I could just do with a bit of help on MOS.

Basically I fitted a second drive as a Gotek just so I could keep my original machine's built in 3" drive original (as it is still in good working condition).

The problem is how do you boot DOS or anything else on drive 1: from MOS!!???

I don't think you actually can, as there doesn't seem to be a MOS command to change which drive is active, and the welcome screen when I turn on my machine says "insert disc in drive 0: and press Ctrl+Break"... It's only once you boot DOS from drive 0: you can then change the active drive and choose drive 1:

But I'd really like to keep my computer original with the 3" drive and just use the gotek external one to boot things up make copies of disks etc. It's not a big deal, I can take out the original drive and put the gotek in instead (and then use the original one as the external drive) BUT I thought another clever Tatung Einstein user may know a hack in MOS to change the active disc drive. As the Tatung 256 only has 1 drive bay, I thought a TC01 user may know if other 256 users perhaps don't...

Can the active or default disk drive just be changed in memory or poked in kinda thing with some MOS commands?? Any help is really appreciated

[vanpeebles]

I can’t help, but I’d love to,know how you connected it to your 256

[soydemadrid]

I can’t help, but I’d love to,know how you connected it to your 256

Hi thanks, using this kit as either internal or external drive. For external all that is needed is a dual ribbon cable, ie it has 3 connectors on - one for the motherboard then two further down the ribbon for the two drives. Also for external 5v power is needed too, but other than that it just works:

https://www.simulant.uk/shop/Tatung-Ein ... ulator-kit

thanks if anyone can help at all

[papahippo]

Hi,

A "thinking outside the box solution" (which you will therefore perhaps regard as no solution at all!) would be to jumper your internal drive to be e drive 1,2 or 3) - this is quite easy, certainly on the original Einstein - and jumper your external drive to be drive 0.

I did something similar many years ago: I had an external drive which could only be drive 0 or drive 1, so I reconfigured my right-hand drive (originally drive 1) to be drive 2, and used the external drive as drive 1.

This must have been easy at the time because when I brought Alberto out of storage without external drive, I forgot that I'd done it, and wondered why my drive 1 wasn't working. The tell-tale power cable sticking out through Alberto's case finally jogged my memory!

Hope this helps - or at least doesn't annoy!

Success!
Larry

[soydemadrid]

Hi,

A "thinking outside the box solution" (which you will therefore perhaps regard as no solution at all!) would be to jumper your internal drive to be e drive 1,2 or 3) - this is quite easy, certainly on the original Einstein - and jumper your external drive to be drive 0.

I did something similar many years ago: I had an external drive which could only be drive 0 or drive 1, so I reconfigured my right-hand drive (originally drive 1) to be drive 2, and used the external drive as drive 1.

This must have been easy at the time because when I brought Alberto out of storage without external drive, I forgot that I'd done it, and wondered why my drive 1 wasn't working. The tell-tale power cable sticking out through Alberto's case finally jogged my memory!

Hope this helps - or at least doesn't annoy!

Success!
Larry

Hi thanks Larry, that is a good idea... How do you actually jumper the original 3" drive though as there doesn't appear to be jumpers on it? Thanks again

[papahippo]

Hi,

I still have the document supplied when I bought my extra drive... but I failed to scan it.. but it's a pretty poor document anyway... Let's see if I can do better!

This mini-howto is based around the original Einstein but most of it should still apply.

(0. I find it comforting to take photos at key stages, in case I forgot how things were connected originally)
1. Power down Einstein.
2. Open case.
3. Find 4 screws holding encased drive unit in place.
4. Loosen all 4 screws but try to avoid letting them fall where they might do some damage.
5. Ease the drive out of the brackets. N.B. If the cabling etc.on Einstein256 is less liberal, you way need to do step 6 first!
6. remove the power connector and the data connector from the drive.
7. Now remove the four screws completely.
8. Slide the drive out of the metal case and lay it down with the component side uppermost and the edge connector towards you.
9. You should see a a 'jumper field' just above teh edge connector with two jumpers actually fitted. See photo.
10. Leave the rightmost jumper alone. Move the leftmost jumper from the position marked DS 0 to e.g. the position marked DS1.
11. Put it all back together, taking care to get connectors - and the drive itself! - the right way up.

Success!
Larry

photos, I hope...
https://drive.google.com/file/d/14h0HEh ... sp=sharing
https://drive.google.com/file/d/14fJ99d ... sp=sharing

[retrogamer]

If Drive 0 is physically missing or not functioning correctly, or if DOS has not been initialised (e.g. you've no system disc) you'll drop into MOS at startup.

Even without DOS, it's possible to use the built-in Read command in MOS to load and run a program from a disc in any drive. You just need to know where on the disc the program resides!

If the program is the only (or first) saved program on the disc, the program is always stored from the same spot on the disc (actually the fifth sector of the third track). So as we know the values, we can load the program from an External Drive by typing:

R 100 E0FF 0402 01 [ENTER]

This works for Drive 1. Simply change the final 01 to 00, 02, or 03 to load from other drives (0-3) as required.

To run the program, type:

G 100 [ENTER]

This relies on the program being the first saved program on the disc in contiguously saved tracks. To ensure the complete program is loaded, the Read command keeps loading from disc until the top of transient program memory is reached, but loading some redundant disc tracks into memory shouldn't adversely affect program operation.

Clearly this is not a replacement for DOS, but it does work