DskTools is a library (libdsk) and application (dsktools) for working with TRS-80 Color Computer (CoCo) virtual disk (.DSK) files in JVC format. No JVC header is created or recognized.
Note: By default the original 35 track (160K) format is supported. Starting with v0.4.0 the dsk_new() API has been updated to allow for arbitrary track/side configurations.
I have a particular fondness for the TRS-80 Color Computer. It was the first computer that I owned and I learned a great deal about programming from tinkering with that machine. Amazingly I still have a functioning device! Using the CoCo SDC from RetroRewind I am able to move files between my CoCo and other devices via SD Card. The Coco SDC accesses files from within virtual disk drives on the SD Card. I needed a way to manipulate DSK files in order to move files to/from my device.
While there are a number of existing tools for working with DSK files, I've never had the opportunity to work directly on a file system. As the DSK format is clearly documented it seemed that DSK files were a good project for learning about the the low-level aspects of file systems.
The original physical floppy disc format is documented here.
Interestingly, Microsoft licensed Basic-69 to Tandy for the Color Computer. This became the basis of the Color BASIC implementation. And the later Disk Extended Color Basic ("DECB") uses an early form of the 8-bit FAT file system from Microsoft BASIC-80. Though most of us know about FAT from PC-DOS and MS-DOS. So this project gave me an opportunity to explore the implementation of a FAT-based system.
The libdsk library provides a number of functions for working with DSK files.
| Function | Description |
|---|---|
| dsk_seek_drive | seek to given track and sector |
| dsk_mount_drive | mount a DSK file |
| dsk_unmount_drive | unmount a DSK file |
| dsk_dir | display directory of mounted DSK file |
| dsk_free_bytes | return number of free bytes on DSK |
| dsk_free_granules | return number of free granules on DSK |
| dsk_add_file | add a new file to the DSK |
| dsk_extract_file | extract a file from the DSK |
| dsk_new | create a new (empty) DSK file |
| dsk_format | format a DSK file (erases contents) |
| dsk_flush | sync directory and FAT to DSK |
| dsk_del | delete a file from the DSK |
| dsk_set_output_function | replace the default output function |
| dsk_rename | rename a file on the DSK |
Working with libdsk is straightforward. Simply include dsk.h and link to libdsk and you are ready to begin working with DSK files.
Below is an example of creating a new, empty DSK file.
#include <stdio.h>
#include "dsk.h"
int main(int argc, char *argv[])
{
// create (and format) a new blank DSK file
return dsk_new(argv[1]);
}And here is an example of mounting an existing DSK file and displaying the directory.
#include <stdio.h>
#include "dsk.h"
int main(int argc, char *argv[])
{
// attempt to mount an existing DSK file
DSK_Drive *drv = dsk_mount(argv[1]);
// display the directory
if (drv)
dsk_dir(drv);
return 0;
}More complete examples of the library and its usage are provided by the dsktools
application and related tools.