Famicom Disk System

Overview

Companies like New Tai Sang Co., Bung Enterprises, Makko Toys Co., Ltd., Hacker International, and others created FDS disk programs that enable disk-to-disk copying of official games.

There are numerous versions of these programs, but for the most part, they all function the same way. Most require the use of a write-modded FDS so that the entire disk can be rewritten.

Programs like the NTSC version of Copy Master can copy using a drive that has not been modded, but the program will not re-write the Nintendo-HVC header on the disk. The disk instead retains the header already written onto it. In this instance, the resulting copy will not be perfect and may not load correctly in different drives since drives are typically adjusted with slight alignment and speed differences.

Disk-to-Disk Copying

Dubbing Boy II

In addition to tutorials in “mooks” like Backup Technique, some companies in Hong Kong produced devices that would enable the connection of two FDS drives for disk-to-disk copying.

One such device is the disk-to-disk copying device, Dubbing Boy II (BP-103). Thanks to Rob Budrick for the magazine advertisement.

To use the device, the FDS that writes the disk is plugged into left side of the PCB (WRITE) and the drive that the disk is read from is plugged into the right side (READ). The FDS RAM Adapter (already connected to a powered-on Famicom) is connected to the upper left connector. The switch at the top left says TEST and COPY. The blue potentiometer next to the two green LEDs is used to sync up the drive speeds between the two FDS motors in TEST mode. Once synced, flip the switch to COPY, push the blue square button on the upper right, and the disk is “Read” on the drive connected to the right side and written to the disk in the “Write” drive on the left side. To verify the disk is written correctly, flip the switch back to TEST and the disk is loaded into the Famicom via the RAM Adapter. A benefit for using the Dubbing Boy II includes the ability to copy disks with copy protection.

A shortcoming is that, much like copying a cassette tape, data degradation occurs with each successive generation of copies, eventually making copying a disk impossible.

Famicom Disk Backup Unit by S.TANJI

Much like the Dubbing Boy II and the Dubbing Cables, the Famicom Disk Backup Unit by S.TANJI allows the copying of FDS disks from one drive to another. Below is an an article from Famicom Kaizou Manual showing how the disk drive-to-disk drive copying unit works. Thanks to Rob Budrick for scans of the article.

Open the images in a new window or tab to see them in full size.

Disk Copying with Copy Utilities

The basic copy utility process is:

1. Insert the disk containing the copy program into the FDS and allow the program to load.
2. Once loaded, the program will prompt you to insert the source disk you wish to copy.
3. Since the RAM Adapter only has 32KB of program memory and 8KB of character (tile) memory, the copy program will only be able to load about half of the disk into the RAM Adapter’s memory before prompting you for the target (re: blank) disk you wish to copy onto.
4. The program will write the data to the disk and then prompt you to insert the source disk once again so it may copy the remaining bytes from the disk into the RAM Adapter’s memory.
5. The copy program will then again prompt you to re-insert the blank so it may finish writing the remaining bytes to the disk.
6. Once the disk has finished the writing and verification processes (via checksum), the program will display “End” or something similar and again revert back to the prompt asking for the source disk to be inserted to begin the copying and writing process anew.

The process must be completed for each disk side. Some programs require the use of a copier device, which contains more memory than the RAM Adapter. Typically, these programs that use the copiers can copy one entire disk side in a single pass. If the blank is unable to be successfully written to, the program will display an FDS Error Code.

Some programs have special features, enabling the copying of copy-protected disks and Game Doctor disks. Some games have hidden copy protection methods that certain copy utilities cannot correctly copy, including games such as Doki Doki Panic and Tobidase Daisakusen (see below). For these games, only certain copy utilities that bypass the copy protection can be used to make usable copies of the games.

FDS Drive Speed

The Makko and NTSC versions of Copy Master include a utility that will test the speed that the FDS drive is tuned to, called “Check Doctor” in the Makko version and “Speed Test” in the NTSC version. Copy Master v1.0 does not have a Speed Test option, and instead shows “Boot Disk” in its place, which just resets the Famicom.

The speeds range from 1 to 9, and the utility will also display “too slow” or “too fast.” According to Tomy at ToToTEK (and Bung/Makko), the speed should be set to 5 with the disk in the drive, which should equal 0 or 1 when there is no disk inserted in the drive. The test should be performed twice in a row, since during the first test the magnetic head position is unknown so the test may show an incorrect speed.

The speed can be adjusted by turning the potentiometer inside the motor with a small flat head screwdriver. Turning to the right slows the drive and turning to the left speeds it up. Use very small increments to make adjustments to the speed, re-testing after each, until the desired drive speed is achieved.

Copy Master Drive Speed Testing

Copy Utilities

The following images are title screens from various copy programs.