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intric8
Seattle, WA, USA
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Posted Sat Sep 24, 2022 2:37 pm

Over the years I've collected/purchased multiple U36 ROMs for my C128D(cr).

The U36 ROM is for an empty socket that the engineers left in the C128 in case folks in the future ever wanted to enhance their machines with programmed ROMs. What a very cool and forward-thinking idea!

Naturally, a lot of people have created some very cool enhancements for that empty socket.

The three I currently have include:
  • Super 81 Utilities
  • KeyDOS
  • GEOS 128 v2 w/ 1571
There are many others, but this is what mine can do.

Super 81 Utilities

This is a very cool upgrade for anyone with 1581 drives attached to their system.
  • It can copy whole disks from 1541 or 1571 format to 1581 partitions.
  • Copy 1541 or 1571 files to 1581 disks.
  • Copy 1581 files to 1571 disks.
  • Backup 1581 disks or files with 1 or 2 1581s.
  • 1581 Disk Editor, Drive Monitor & RAM Writer.
  • Perform many CP/M and MS-DOS utility functions.
This is generally my go-to because it's simple and easy for me to wrap my head around it. There are some that have so many features, it boggles the brain (like... the next one).

IMG_9786.JPG

KeyDOS (Antigrav Toolkit)

This ROM has so many "pro" features, it's kind of ridiculous. If you don't believe me, check out its 54-page manual! And, it is compatible with pretty much everything under the sun.

How all of this fits into 32KB is amazing in its own right.
Screen Shot 2022-09-24 at 2.21.49 PM.png
Screenshot from the manual. I wasn't about to type all of that. ;)


What's also cool about this ROM (and maybe all of these ROMs? But this one specifically explains how to do it in the manual) is that it can be installed in a Commodore REU expansion rather than the socket inside the machine. It would require a very minor mod to the PCB of the REU, but nothing super scary. Neat idea either way.


GEOS 128 v2 w/ 1571

This ROM allows for some of the GEOS boot code to be loaded from a ROM chip instead of off of a floppy. It doesn't really speed up the boot-up process that much, but it does speed things up quite a bit should you ever need to do a reboot, and other occasional processes. Obviously loading off a ROM is going to be faster than most disk reads - even compared to a 1571. However, my current setup boots off of a 1581 on Drive 9, so I'm not using this one anymore. They make a ROM for folks with 1581 drives, too - but only when set to drive 8. I can flip my drive to 8 no sweat, but it's not my preferred setup right now so I have just left things as-is.

I love my current setup so much, I plan on showing you all more about that soon.

There are several more ROMs that I'm aware of. They are:
  • Basic 8 ROM
  • File Browser v6
  • Servant 128 (I think I owned this one once but lost it)
  • Turbo Assembler
Do any of you use the U36 expansion ROMs? What's your favorite?

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BloodyCactus
Lexington VA
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Posted Mon Sep 26, 2022 6:25 am

Very cool, I only have the megabit 16k/4mb rom and its amazing. Its such a cool feature to have I think on the C128

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intric8
Seattle, WA, USA
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Posted Mon Sep 26, 2022 7:56 am

@BloodyCactus what software does your megabit have loaded? Is it the menu you see in the photo here?
I only have the megabit 16k/4mb rom and its amazing. Its such a cool feature to have I think on the C128
Did you buy it somewhere, or build it yourself?

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intric8
Seattle, WA, USA
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Posted Mon Sep 26, 2022 8:00 am

Update: I've added a screenshot of the Super 81 utilities screen I can access with my current U36 ROM. It identifies and displays the attached drives with their IDs, which I can then use to move or copy files back and forth.

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BloodyCactus
Lexington VA
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Posted Mon Sep 26, 2022 10:48 am

My megabit dates to 2010 when I got it from Dan Newbury, one of his last ones back then. When the c128 has booted up you can hit HELP key to get to the menu inside it; Its a rom chip on pcb with a wire hook for keyboard access.

It has in it;
  • Merlin 128 v1.0
  • Promos 2.0
  • My Disk Editor
  • Function keys
  • Viza Write 128
  • Viza Star 128
  • Seq Reader 128
  • Begin & End Adrs
  • Fastrac File copy
  • Directory Editor
  • Color 80 column
  • Basic Data Maker
  • Monitor 64
  • Basic Merge
  • Basic Merge +
  • Maverick File Copy
  • Maverick Track Editor
  • Single 41 Data copy
  • Dual 41 Data Copy
  • Single Nybbler
  • Dual Nybbler
  • Single 81 Data copy
  • Maverick File Tracer
  • Maverick Track & Sector Editor
  • 64K VDC RAM Test
  • REU Test

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intric8
Seattle, WA, USA
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Posted Mon Sep 26, 2022 11:34 am

I've ordered a reproduction of the Megabit 128 by DC Newberry, using surface mount components (only $30). This guy also makes an internal 232 wifi modem for the C128. He's in the process of trying to build one for the C128D - the metal case is apparently a bit of a challenge for the antennae.

Anyway, very cool guy. Looking forward to checking it out!

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Zippy Zapp
CA, USA

Posted Tue Sep 27, 2022 7:49 pm

Hey I just got one on eBay for $30 too. I had been looking for an already made up one because I am way behind in my DIY projects.





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