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Category: Commodore

JaffyDOS is a custom kernal for the C64/SX64 with enhancements for SD2IEC.
Filebrowser and Kernal modifications by:

2017-07. Version 1.2 (Recommended)
* Includes saveroutine fix from v1.1.
* Filecopy works again with files up to 201 blocks.
2017-07. Version 1.1 (Obsolete. Don’t use)
* Quickfix for those who experienced problems.
* Saveroutine fixed. Some games bank out basic before saving and could cause the save to fail (e.g. highscore).
* Filecopy temporarily limited to 152 blocks because of the savefix.
2017-04. Version 1.0 (Obsolete. Don’t use)
* Initial release.


* Jiffydos protocol and DOS wedge.
* Customizable color scheme.
* Customizable F-Key assignments.
* Built in filebrowser(FB) supporting 590 entries.
* Built in file copier.
* md64/md71/md81 to make a d64/d71/d81 image.
* CRSR moves to beginning of the line when executing F-Key.
* When loading a file, the start- and end address are displayed.

Tape- and RS232 support are not available.

Use the patcher to create JaffyDOS ROM. You must provide an original Jiffydos ROM and be a licensed Jiffydos user to use JaffyDOS in your system. You can purchase Jiffydos from


Thanks to Tom-Cat, Erhan and Lemming for feedback and extensive testing. Your help made it possible! 🙂
Additional testing for version 1.1 done by Snear and Marty/Radwar.


No warranties whatsoever, use it at your own risk 🙂






Enter the filename of the original Jiffydos ROM.


Create a personal color scheme or select one of the predefined schemes.


The F-key commands can be re-assigned.






Default F-key assignments: (customizable with the patcher)
F1 = @"$"       DIR<CR>
F3 = %          LOAD and RUN<CR>
F5 = @"CD/:     CD directory/mount diskimage<CR>
F7 = @"CD<-"    CD parent dir<CR>
F2 = /          LOAD<CR>
F4 = @"XS/:     Mount swaplist<CR>
F6 = @  "S:     Scratch file
F8 = @FB:       Start FileBrowser<CR>

<CR> Executes the command automatically after pressing the F-Key.



DOSWedge Commands:
@                   Read disk drive error channel
@$                  Display disk directory
@#device            Set device number
@C:newfile=file     Copy a file on the same diskette
@I                  Initialize disk drive
@N:diskname,ID      Format (NEW) disk
@N:diskname         Short NEW
@Q                  Disable JaffyDOS
@R:newname=oldname  Rename file
@S:file             Scratch file
@UJ                 Reset disk drive
@V                  Validate disk
/filename           LOAD program
£filename           LOAD program
%filename           LOAD and RUN program
↑filename           Load and RUN program
←filename           Save program
'filename           Verify program

<SHIFT>+<RUN/STOP>  Load & run first program on disk
<CONTROL>+<D>       Default drive toggle
SYS 64000           Re-enable JaffyDOS functionkeys and commands



New DOSWedge Commands:
&filename               Verify program
$                       Display disk directory
@8                      Set device number to 8
@9                      Set device number to 9
@1x                     Set device number to 1x
@FB                     Start FileBrowser (or @F)
@MD64"filename.d64      Make .d64 image
@MD71"filename.d71      Make .d71 image
@MD81"filename.d81      Make .d81 image



Make image; D64, D71 or D81:
* Use single quote only in the command.
* Max 16 chars in filename+extension(.D64/.D71/.D81).
* File extension is mandatory.
* You must mount and format the diskimage afterwards.


SD2IEC Supported commands:
See the SD2IEC readme-file here
JaffyDOS does not require extra quotes in some of the commands.


Additional commands which are not mentioned here but are referenced in the Jiffydos manual, have been removed to fit the new features in JaffyDOS.


CRSR UP    = Up one position.
CRSR DOWN  = Down one position.
CRSR LEFT  = Up 10 positions.
CRSR RIGHT = Down 10 positions.
F1         = Go to First entry in the list.
F2         = Refresh.
F3         = Go to Last entry in the list.
F7         = Quit.
RETURN     = Load & Run / Enter dir / Mount image or swaplist.
Backspace  = Exit dir / Unmount image.
$          = Display "real" dir.
+/-        = Increase/Decrease device number.
CBM C      = Filecopy. Load(copy) file into memory, see below.
CBM V      = Filecopy. Save(paste) file to disk, see below.

* 590 entries allowed in directory.
* Remembers last position when returning from a directory or unmounting an image (one level).
* Files with extension .D64/.D71/.D81/.M2I/.DNP are mounted as disk images using @CD:
* Files with extension .LST are mounted as a swaplist using @XS:
* Character set is changed to uppercase when entering a diskimage.


Filecopier (for small files, only available in FileBrowser)
1. Hold down the CBM-key and press “C”. Selected file will be loaded into memory.
2. Go to destination location with filebrowser.
3. Hold down the CBM-key and press “V”. File is now saved into current location.

* A file can be copied from/to the SD2IEC filesystem, a mounted image or swaplist, or from/to another device number/type.
* It is not possible to copy(CBM-C) a directory or a disk-image.
* Selecting / copying multiple files is not supported.
* You can not paste(CBM-V) if a file has not been loaded or if the copy phase resulted in an I/O error.
* I/O Errors will be reported.
* Max filesize: 201 blocks. (exceeding the size will cause a crash).
* File can be re-saved(CBM-V) several times at multiple locations.
* You have to re-load a file (CBM-C) if you exit and return to FB.



The Final Chesscard by TASC was released in 1989 for the Commodore 64/128 and PC. The C64/C128 version plugs into the Expansion(cartridge) slot and the PC version comes with an ISA Card.

The Chesscard forms a stand-alone computer with 32K of ROM, 8K of RAM and an extra CPU running at 5 Mhz. Program software was delivered on disk for the PC and the C64 software is loaded from an additional 32K ROM on the C64/128 cartridge.


The Final Chesscard C64/C128

Unfortunately my Chesscard only displayed a black screen with white stripes, so I began to investigate it.

The C64/C128 Chesscard has two 32K ROMs which I dumped with an eprom reader. One ROM with software for the external CPU and the other has software for the C64. This also revealed my Chesscard was in the german language.

The C64-ROM consists of two banks, both 16K at $8000-$bfff. The bank is selected by setting $DE00 to $40 or $41. The Chess-ROM is 32K at $8000-$ffff and boots independently with reset vectors pointing to $FF22.

I needed a way to test the ROMs. The same company was involved in making the “Final Cartridge III” which has 16K sized banks and uses $DE00 for bank swapping. I created a TFC3-type cartridge ROM for emulators(.crt) and wedged in code to set $DE00 accordingly. The Final Chesscard now started up in the Vice emulator, displaying a black screen with white stripes.

Now it became much easier to debug. After examining the code, I could see the “black screen with stripes” was waiting for the extra CPU to acknowledge it was running (possibly these two communicate with each other using zeropages $04-$0e). I removed the checks and had the Chesscard running graphically, the chess engine itself was of course not working.

The Final Chesscard in Vice (Working partially without the extra hardware support)


I eventually figured out the extra CPU did not start up properly. I took out my desolder gun and removed the CPU. It was tested OK on another equipment. After desoldering the crystal I noticed that one of the legs was broken, and while at it, I decided to clean up the whole PCB for documentation purposes. You will find scans and pictures of the PCB below.


Component list:
74LS32 x 2
74LS374 x 2
SRAM = 8Kx8 TC5565/MCM6064
CPU = G65SC02P-4
ROM1/ROM2 = 27256 Eprom
D1-D6 = Diode 1N4148
ZD1 = Zener diode 2V7
C1-C2 = Tantalum 1uF 35V
C3-C6 = Ceramic 0.1uF
C7-C9 = Ceramic 1.0nF
C10 = Ceramic 0.56nF
X1 = Crystal 5Mhz
Resistor 2.2 KOhm x2
Resistor 680 Ohm x2
Resistor 330 Ohm
Reset button


Everything back in place and all IC:s socketed.

Final mount. The Final Chesscard is now fully functional with english language.

ROM Downloads:
There are two language options for the Chesscard; english and german. The language is hardcoded on the ROM. The english ROM has been quite hard to get hold of(until now). There are demo-versions out of both, which are easy to find, but they are not compatible with the ROM version.

With information from studying the code, I managed to make a C64 tool to extract the ROM and thanks to Ratuv at Lemon64, who kindly run the tool on his english Chesscard, there is now an english ROM available for download.


Here are scans of my Commodore Service Bulletins by RCA Service Company.





GEORAM is a 512K memory expansion unit made by Berkeley Softworks for use with GEOS. It can also be used for other programs, but is not compatible with Commodore REU. There are several programs that support GEORAM though, for example Maniac Mansion GOLD.

The Shareware PLUS Commodore 64 & 128 Blog has redesigned the GEORAM to fit inside a standard cartridge case and it does not require a heavy duty powersupply like the Commodore REU would. You can find the new GEORAM at The Shareware PLUS Commodore 64 & 128 Blog


The new GEORAM comes with a box and a manual.


Just for comparison. The original geoRAM to the left is very bulky and the PCB had to be exposed so it would fit into the C128D. I was always afraid to break something by mistake when handling the geoRAM. The new design is much better.


Contents of the original geoRAM and the new GEORAM.


ZoomFloppy does not come with a case so I searched around and found one which was a pretty good fit. I found the case on eBay listed as “Type Z80” with measurements of 119x90x38mm and cost me €7 including shipping. The PCB is fastened with 7mm high standoffs, you need to drill holes into the case to match the holes on the PCB. Here are some pictures of the result.

Spectacular Copy Turbo to Disk, SCT2D, a widely used tool for preserving turbotapes got another update. This time completely rewritten from scratch with support for several fastloaders and a built in head alignment.

You can find the tool at CSDB,

SDT2D Changelog:

v2.0. Written from scratch by SAILOR/TRIAD
* All functionality from earlier versions included.
* Fastsave I/O for 1541/1581/DolphinDos devices.
* Added support for JiffyDos.
* Built-in HeadAlign v1.1 by ENTHUSI/ONSLAUGHT. Press RESTORE during transfer
to restart and/or enter HeadAlign and RESTORE again to exit HeadAlign.
* Safe(slow) saveroutine using CHROUT for mass storage devices.
* Savespeed comparsion of a 180 blocks file (mm:ss):
IDE64 00:08
DolphinDos 00:13
SD2IEC+JiffyDos 00:18
1581 fast I/O 00:19
1541 fast I/O 00:27
SD2IEC 00:54
1581 slow 01:03
1541 slow 02:11

v1.2 by SAILOR of TRIAD
* Fastsave I/O for 1541 drives.

v1.1 by WACKEE of ARISE:
* Automatic replacing of invalid chars (,*?) before save [option].
* Accurate block size calculation.
* Proper handling of 0-byte files.
* Fixed resave on diskerror.
* Rename without space-fill.
* Tapeload with sound.
* Changed default settings.

v1.0 by SAILOR of TRIAD:
* Asks for disk change if file is larger than free blocks on disk.
* Resave option on diskerror.
* Option to rename file.
* Can use other devices than #8.
* Autotransfer mode option.
* Load error detection.



My friend Xiny6581 at the asked me to take a deeper dive into a tape he had gotten for preservation.

You can read his findings on the tape at:The True Art of Data Archaeology, but we both felt there was more to find out on these tapes.

We came pretty quick to the conclusion the tapes were disk backups saved to a turbotape format. None of the current turbo transfer tools were able to identify the files, nor the format properly.

I made a tool to inspect the raw turbo-data on the tape. The files start with a standard turbo-tape header and the rest of the data is custom turbo-tape. With this information i made a tool which saved the raw data to disk.


After the turbo-tape header, a custom header follows with $02a1 bytes of data. The header has checksum(Yellow) and a name(Orange). The name is something you’d type in since it does not reflect the name of the disk. When restoring, the original program probably looked for “a bunch” of $02;s plus a sequence of $09,$08…$01,$00 and everything after those bytes is data.

Four consecutive files on the tape has the same name in the custom header why I came to the conclusion each disk was split into four files.

I was able to determine the size of the header by assuming the first block of data from the tape was from the lower tracks(sectors) of the disk. Therefor the bytes $01,$0a is a track/sector-link(lightblue) and the bytes $a9,$0a,$48,$a9,$00, which translates to LDA #$0A/PHA/LDA#$00, is programdata(lightgreen). This is how the data is structured on a disk.

Now i had found an offset for the disk data. I knew every $0100 bytes after the header corresponds to a sector on the disk. However, this was the easy part. I got pretty fast aware of the fact the sectors were in no logical order. After saving all data out, I had 9 backups of disks giving a total of 683*9(=6147) sectors that had to be puzzled together.

I started reconstructing the directory tracks. Track 18.0 holds the disk name and was found on all backups in the third file at position 0x11c1. It will also link to track 18.01 (hex $12,$01) which is the first block with filenames and track/sector links to the files.

One of the games was Flight Simulator II. Knowing that it is a full disk copy with the same placement of sectors(data) throughout the disk compared to the original game caught my interest. I made a tool which checksummed every block of $0100 bytes from the four files and compared it to every sector on the original disk. When there was a match, I knew which memorypositon in which file corresponded to a track/sector on the disk. After a match, the tool would not check the same sector twice.

I got out a fair amount of matches, not all though, since many sectors were empty and therefor matched multiple sectors. After running the same tool on another disk, Ultima II this time, it returned many identical matches with the first run. I knew i was on the right track(pun intended) and it looked like the layout was same for all disks.

With the result from the checksum runs on a couple of more disks I (roughly) knew the following:
File 1: Tracks 01-08
File 2: Tracks 09-16
File 3: Tracks 17-25
File 4: Tracks 26-35
The sectorlayout was not the same throughout the four files, but I could see a repetitive pattern which filled in some of the blanks after tweaking my tool a bit.

With the tables generated, and with the information in them, I wrote out the files to diskimages. Now I had 9 disks, with partially written data to them. I tried loading some files, but they often halted in the middle of loading since it hit an empty(zero-filled) sector telling the drive it is the last sector to load. There is no data written on those sectors either.

This is where I got ideas for another tool, and where I searched for partial matches from other releases found on CSDB. One disk was Summer Games and I knew it has a number of files which matches with the data written (and not yet written) to the diskimage.

My new tool would try to extract a file from the images I built. When it hit the track/sector links $00,$00 (i.e. empty sector) it would store the current track/sector and know which sector(and which track) was missing data. I also had pointed out the corresponding (complete) file and the tool searched/compared where identical data ended. From that offset it matched ($0100-2) of data from the four files which had not yet been written to disk.

When the data was identical, I got a visual feedback to confirm if the (next) track/sector link was within reasonable limits. I was able to verify it with the earlier information about which files held which tracks and if the sector links follows the pattern how a file gets written to disk (i.e. 01,11,02,12,03,13,04,14…).

With a couple more files from other games, and with my tool, I was able to reconstruct all track/sector data for all the 9 disks :).


However, we still don’t know which tool was used for this backup, if you have any information, please let me know.


A couple of pictures of my Load-IT by Mills. I assume its a late model since everything is combined into the same PCB. Other Load-IT datasettes i own have a separate PCB for the meter.






I got a bunch of disks for transferring. As a routine I do an ocular inspection and make sure the disks rotate before starting the transfer. The only problem was that these disks failed on both parts.

The disks came from a storage unit that had a water leak and the disks were soaked with a mix of water and concrete dust.

Stains of concrete dust. Trying to rotate the disks by hand made a grinding noise. Nothing you’d put in a drive.

The disks were warped since the cushion inside the jacket had gotten wet. No wonder these disks didn’t rotate.

I needed a new disk jacket and to be able to clean up the disks before i could start reading the contents. The disk jacket I got from a donor disk. I used antimagnetic scissors to cut open the disk jackets, both the donor and the disks that I wanted to preserve. The magnetic disk can be moved slightly off-center to gain more space at the top so it won’t be damaged while cutting open the jacket.

When removing the disk, do not touch the magnetic surface. A good tip is to wash your hands with dish-washing liquid to remove grease from your fingers before starting. The disk can be slid out without needing to touch the magnetic surface. You can give the magnetic disk a push by the center hub ring or by the outer edge.

When the magnetic disk is out, use your thumb and pointer finger to hold the disk by the center hub ring and the outer edge. Alternatively put a couple of fingers through the center hub ring. Again, avoid touching the magnetic surface.


I had the disk under running water to rinse the dust off. With a few drops of dish-washing liquid on the fingers of my other hand, I carefully cleaned the surface. I started from the center hole and moved straight out to the outer edge.


Let the disk air dry. Dry wiping is likely to damage the surface. On some stains (or mold!) I used 90% isopropyl alcohol with clean cotton.


After the disk had dried, it was inserted into the donor jacket and I was able to get a good read of the disk.

Spectacular Copy Turbo to Disk, SCT2D, has become a widely used tool for preserving turbo tapes. It was originally part of the “Spectacular Copy” suite by Stephan Senz. “Turbo to disk” was extracted and has undergone many improvements on the way.

Latest addon to the tool is a Fast I/O save routine for 1541-family drives.

You can find the tool at CSDB,

SDT2D Changelog:

v1.2 by SAILOR of TRIAD
* Fastsave I/O for 1541 drives.

v1.1 by WACKEE of ARISE:
* Automatic replacing of invalid chars (,*?) before save [option].
* Accurate block size calculation.
* Proper handling of 0-byte files.
* Fixed resave on diskerror.
* Rename without space-fill.
* Tapeload with sound.
* Changed default settings.

v1.0 by SAILOR of TRIAD:
* Asks for disk change if file is larger than free blocks on disk.
* Resave option on diskerror.
* Option to rename file.
* Can use other devices than #8.
* Autotransfer mode option.
* Load error detection.



Xiny6581 has made a speed comparsion between SCT2D v1.1 and v1.2. Make sure to read his excellent tutorial on preserving tapes at