MFM disk emulator ( ST506, ST412, ST225 ) based on DE10-Nano board
This is a new follow-up project from the RL01 / RL02 disk emulator, also based on SoC/HPS
environment with the DE10-Nano board: https://github.com/pdp11gy/SoC-HPS-based-RL-disk-emulator .
It is also based on the DE10-Nano with another I/O interface. Details on my homepage, www.pdp11gy.com
All sources with environment setup are located in the zip-folder MFM-disk_Emulator_SoC_v1_0.zip
The project provides real time decoding and encoding. As with the RL01/RL02 emulator project, it is
intended to save the data in an .dsk file to be also compatible with the SIMH project.
Currently, it is possible to read a complete disk, one cylinder or one treck. The real time decoder
is also able to provide MFM gap recording. This is necessary in emulator mode because the former disk
manufacturers did always use a different servo/header format ( At low level format ).
The emulater saves the data in a .mfm file which contains the decoded data with all servo/header
information extracts the user/raw data and save it in a .dsk format to be also SIMH-compatible. Additionally,
the MFM-gaps are stored in a .gap file for the emulator mode. More details on my homepage + user manual.
A detailed description with hints and explanations, open points+solutions is in the document MFM_debug.pdf
At the moment I don't have the possibility for further analyze this problem in the DEC environment
because I do not have the necessary vintage hardware and also not the necessary environment around.
Unfortunately, I also do not have an up and running MFM-disk based PC at the moment.
Further development and remarks
In this project, the disk data are stored in a file, such as diskinfo_1. The number of revolutions(RPM),
=index frequency of the disk is detected automatically. Maybe someone can get data from another
disk and edit a corresponding disk file. 16 (0 to F) disk files can be used.
Furthermore, it is planned to bring both interfaces together like in the overview.pdf dokument.
A full, ready for use configured SD-card-image for the DE10-Nano Board is also available.
Details will be published on my homepage, www.pdp11gy.com and in the manual.