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TashTwenty: Single-Chip DCD (Hard Disk 20) Interface

tashtari

Well-known member
I haven’t tried deleting the files on the the 6.0.8 image and replacing them. Should I try that?
I heard last that you were getting this flickering issue whenever you tried to boot either the 6.0.8 or 4.1 image with the HD20 startup disk. What changed to make it work now? I feel like I've seen the issue with the window not opening (or at least, opening to be that tiny little black rectangle that you can't do anything with in the first picture) before but I'm not sure, I'm wondering if it's got something to do with the fact that the secondary image was formatted with 6.0.8...
 

Zhinü

Well-known member
Oh, I did what you recommended a week ago. I opened the HD20 up in my IIsi, deleted all of the original system files, and copied on the files from my boot disk.
 

Zhinü

Well-known member
Oh, another piece of info. The HD20 cable works straight out with no modifications. AFAIK you can swap this into a HD20 without too much issue. In fact, you won’t even need a power cord for it.
 

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tashtari

Well-known member
Oh, I did what you recommended a week ago. I opened the HD20 up in my IIsi, deleted all of the original system files, and copied on the files from my boot disk.
Ahh, okay, I remember. I think that's what happened with the window being messed up, 6.0.8 wrote something that 3.x or whatever couldn't understand. I'm still wondering what the heck with the two drives having the same icon, though...
Oh, another piece of info. The HD20 cable works straight out with no modifications. AFAIK you can swap this into a HD20 without too much issue. In fact, you won’t even need a power cord for it.
Cool, thanks for proving it. =)
 

Zhinü

Well-known member
And... The First HD20 Retrofit project is complete! This unit looks like a normal HD20 save for the SD card sticking out the back. While the insides are messy, it'll work until better mounting solutions exist.
 

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CC_333

Well-known member
@Zhinü What kind of Mac is that? A Macintosh 512k with the badge on the front instead of on the back?

@mg.man That pretty much proves my point!

In many dimensions, the Emu and TashTwenty are similar, where they differ, though, is length; the Emu is considerably longer (to accommodate its more advanced hardware, no doubt).

c
 

Zhinü

Well-known member
@Zhinü What kind of Mac is that? A Macintosh 512k with the badge on the front instead of on the back?

@mg.man That pretty much proves my point!

In many dimensions, the Emu and TashTwenty are similar, where they differ, though, is length; the Emu is considerably longer (to accommodate its more advanced hardware, no doubt).

c
It was a Dealer 128K that was upgraded to a 512K either third party or by Apple. I assume since it was on display and the 128K/512K look very similar, they slapped the badge on front to say “yep, this is a 512K!”
 

CC_333

Well-known member
Interesting. Never seen one like it before!

I see you're in the SF Bay Area (I think). Which part?

c
 

CC_333

Well-known member
I understand. Neither am I. General region (east, peninsula, north, south) is enough.

I'm in the East bay too!

c
 

mg.man

Well-known member
that was upgraded to a 512K
FWIW, I was working for IBM back in '84 and we had one of the original Macs (behind closed doors) to check out all the hullabaloo about this WYSIWYG stuff... 😉 Of course (like most) we quickly discovered 128k was not going to cut it, so ordered the 512k "upgrade". It came in a box with a Macintosh512k badge (to replace the "Macintosh" one on the back). Since the Mac was in my custody, I got to install it. I was also allowed to keep the original 'board - but what happened to that has been lost to the passing of time... 😞
 

mg.man

Well-known member
now have all my TTs working - both with the previously flaky (2gb)
Spoke too soon. 2gb "generic" uSD will work once, then throw up the flashing floppy on subsequent boots. The 4gb card works every time.

Not sure what to conclude from this, but there seems to be some sensitivity around which uSD you use - at least with the SparkFun adapter. I'll try removing the pull up resistor and give the 2gb one last spin... stay tuned.
 

mg.man

Well-known member
I'll try removing the pull up resistor and give the 2gb one last spin...
No dice... just the flashing floppy. Swapped for the 4gb, booted straight away.

So, my limited experience seems to align with @dochilli, some uSD cards work, some don't. 🤔 I'll do some more testing when I have the new uSDs I've ordered.
 

tashtari

Well-known member
And... The First HD20 Retrofit project is complete!
Nice!
TT 1.0 confirmed booting from floppy 2 port on a IIx with ROMinator
Cool! Is this just with the two-partition image or did you try the three- and four-partition images too?
Not sure what to conclude from this, but there seems to be some sensitivity around which uSD you use - at least with the SparkFun adapter
I am definitely curious to see what happens when the boards with the Adafruit board start getting assembled, whether this pickiness rears its head or not. It's tempting to blame the SparkFun board given how much trouble I've had with them, but we must do Science...
 

tashtari

Well-known member
Thread Rollup

There's been a lot of activity lately, I thought it might be a good idea to repeat some key things...

Links:
Prices and ordering info (shipping not included):

Kits:
$17TashTwenty Tiny by @demik, including ribbon cable (supports full-size SD cards, fits in a Hammond case)
$17TashTwenty Rev 2 by me (smaller, less soldering)
Optional Extras:
$5Transcend 4 GB microSD card (known to work, will program with demo image)
Spare Parts:
$1.75Programmed PIC16F1704
$4"DB"-19 solder cup connector

Please understand (covering my ass): No warranties or guarantees of any kind are provided, no returns, no refunds, no regrets. Kits require skilled assembly. Firmware has behaved pretty well so far but is still experimental and may have serious as-yet-undiscovered bugs. Firmware updates may be provided but require the use of a PIC programmer (which is not included). Technical support is provided via this forum on a best-effort basis.

If you want to order a kit, send me a direct message and we'll get things rolling! I've discovered pirateship.com, so shipping (especially domestic shipping) should be cheaper now, as long as I don't run out of boxes to put things in...
 

tashtari

Well-known member
I'm still wondering what the heck with the two drives having the same icon, though...
Okay, no longer wondering - this seems to be a quirk of System 3.2, not of the Hard Disk 20 patch. I made up an image with four different icons on four partitions, and while the correct icon displayed in the initialization and erase-disk dialogs, the desktop icons were all of the first disk.
 

ktkm

Well-known member
Well, shipment to Sweden took a good while, but my TashTwenty Tiny is assembled and ready for a test drive. It was sure fun to solder, I enjoyed every second of hiding in the basement. Next, I’ll start by doing some reading up in the thread regarding formatting and SD card convolutions.

ktkm_assembled_tt.jpg
 

tashtari

Well-known member
my TashTwenty Tiny is assembled and ready for a test drive
Nice!

Talking of images, I've created a more comprehensive set for interested parties to use... this zip file includes nine images ready to write to an SD card, each with an HD20-sized system disk in the first partition (3.2, 4.1, and 6.0.8) and one, two, or three blank 100 MB partitions after that. The current trend suggests that only the 512K/Ke/Plus support three or four devices (other Macs, when presented with three- or four- device chains, will for some reason ignore all but the first) but I would love it if someone found an anomaly in that trend...

Bonus, their icons are Clarus, Steve Jobs, Bart Simpson, and Hobbes.
 

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ktkm

Well-known member
At last! It took a couple of efforts and SD cards. It didn’t like my two SanDisk 64 GB XC and 4 GB HC, respectively, but the PNY 16 GB that came with my MacSD went through. I’m so relieved. Next up I want to figure out the Icon deal! :)

ktkm_assembled_ttt-05.jpeg
 

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