A Tutorial On Disk Images

One of the most frequent questions that come up in dealing with Color Computer disks is "How do I move the data from my old disks over to my PC?" When discussing the moving of files between a NitrOS-9 or Disk BASIC disk, the physical disk media is of no concern to ToolShed -- in fact, this software does not even know how to extract information from a physical diskette. What ToolShed does understand is the logical underpinnings of the RBF and Disk BASIC file systems, and how to properly manipulate files at that level.

The fact that ToolShed is agnostic to physical media begs the question: how does one transfer the contents of a physical disk to a location where ToolShed can work on the image, and vice versa? The answer is dependent upon the host computer.

Disk Extraction Under Windows/DOS

For the example below, we will assume that the 3.5" 720K floppy drive is A:, and the 5.25" 360K floppy drive is B:.

The tool required to transfer DSK images to floppies under DOS/Windows is DSKINI.EXE.

Once DSKINI.EXE has been downloaded and extracted, call up a Command Prompt window and insert a blank 5.25" 360K diskette into drive B. Presuming the image being transfered is nos96309l2v030200_ds40_1.dsk, type:

DSKINI /T40 /D B: NOS963~1.DSK

Once the transfer completes, you should have an exact image of the disk on the floppy.

Disk Extraction Under Linux

For Linux users, you will need to download the fdutils package. Once installed, insert a blank floppy into your drive. It will be either /dev/fd0 or /dev/fd1. For this example, we assume /dev/fd1.

You must tell Linux the type of disk in the drive:

setfdprm /dev/fd1 coco40ds

Now you can format and transfer the image:

fdformat /dev/fd1
dd if=nos96309l2v030200_ds40_1.dsk of=/dev/fd1

Pathname Elements

Since ToolShed runs on various platforms, the , (comma) character is used to differentiate between host file system pathnames and paths within the image.

Example: Copying a file TO an image

os9 copy test1 os9.dsk,

Example: Copying a file FROM an image

os9 copy os9.dsk,DIR1/DIR2/test2 /

Note: The comma is present in both arguments if both are disk image paths.

Support for HDB-DOS

ToolShed supports specialized path symbols for HDB-DOS hard disk images. The : (colon) allows you to select which disk image is active:

decb copy disk.dsk,NEW.DAT:3 disk.dsk,OLD.DAT:23

The + specifies an offset to share a hard disk with OS-9:

decb list -t hd.img,NEW.BAS:3+1348276