The Discovery Cartridge is an excelent digital copier created by Richard Adams president of Happy Computer for the Atari ST/STe machines. It is capable of copying almost any kind of ST protected diskette as long as you have a correct control file.
Presentation of the Discovery Cartridge from Happy Computers:
"The Discovery Cartridge's advantage over other disk copying or improvement software and hardware is the HART chip. HART stands for "HAPPY ATARI ROTATING THING". This custom made integrated circuit was designed by HAPPY COMPUTERS specifically to allow the full range of floppy disk reading and writing that could be needed with your Atari ST/MEGA computer. The limitations of the floppy disk controller chip built into your computer disappear. With the correct drive connected, and the proper supporting software, your computer can read and write virtually any floppy disk format. Using the standard 3.5" floppy drives for the computer, the immediate benefits are the ability to backup disks that you cannot ordinarily backup. The Discovery Cartridge also allows a variety of options that fulfils the wish list of most Atari computer users, so far as the disk system is concerned."
To get knowledge of the DC first read this document "Introduction to the discovery cartridge, installation, etc." as well as Important DC Information.Back to the top dbackup document (that I have reformatted for easier reading). It explains how to create the file to control the backup process (the dbkupcf.s BC input file) and gives technical details on the mfmbtemp output file produced by the dmfmbkup program.
The schematics of the discovery cartridge can be found here. This extremely simple system is
build around a custom chip called the HART chip.
The DC could be sell with few options that allowed to add EPROM's, clock/calendar circuit PCF8573 and circuitry for extra floppies.
The "basic" model (the one without option) only contains the HART chip, a TTL inverter package, a crystal, a few passive components. The DC is connected to the 68000 address and data bus through the cartridge port. Here is a picture of the basic board.
Note that the imaging process is not fully automated and requires the user to provide information about the protection mechanisms used on the diskette to backup in a control file described below. Happy Computer was suppose to provide on request (and did provide) control files for making backup of specific diskettes. However the company is long time gone and there is a need to help user on the analysis process in order to create new command files (see programs below).Back to the top archive.
For an unknown diskette you can use this program to help you create a new BC files. Back to the top
- The dmfmbkup program is required to use the DC hardware. Here is the original floppy V2.7 from Happy Computers (latest release) as well as few others non official releases of the dmfmbkup program.
- There is also this program written by Larry Layton that helps in writing BC file.
- My Decode Program : The mfmbtemp file produced during the backup process is a binary
file and it is therefore not possible to directly look at the information inside
this file. I have written a program that reads the binary file and produce a "dump" of the
content. It is experimental and currently it has the following features:
- It interprets all the codes ($0000 to $000F) and associated values of the mfmbtem file, and displays the contents of the tracks in hex and character mode.
- It fully decodes the MFM flux (stored in $000A records) received from the DC. For that matter the program internally mimics a FDC with a PLL data separator, an AM decoder, a DSR, a CRC generator/checker,... This allow to read in MFM flux and to display the decoded content of the GAPs, ID, and DATA fields with information on good/bad CRC, sector number, size, etc...
- It also has the capability to display semi-graphically the flux from the DC cartridge along with the decoded data.
- The program run on PC and it also run on Atari (but slow).
Here are some pictures of the DC cartridge: