D. P. Johnson -- SDisk/SDisk3 Floppy Disk Drivers

SDisk is an improved floppy disk driver module for OS-9 that replaces the CCDisk module in the OS9Boot file provided with OS-9 Level I for the Radio Shack Color Computer (CoCo 2). SDisk3 similarly replaces the CC3Disk module in OS-9 Level II on the CoCo 3. The matching SFormat program replaces the original Format program.

SDisk and SDisk3 features:

The new direct sector read/write functions allow software such as the PC-XFER Utilities from D. P. Johnson, and the MSF file manager from Clearbrook Software Group, to access disks that use formats other than OS-9, such as CoCo Disk Extended Color BASIC (DECB), FLEX, MS-DOS, and CP/M.

I licensed the SDisk and SDisk3 drivers and SFormat program from D. P. Johnson, then modified them for my ST-2900 and DMC products.

On 2013-May-31 D. P. Johnson (Dan Johnson) gave me permission, via e-mail, to release the source code and binaries of his SDisk and SDisk3 drivers as free software.

The four disk images available below are as I received them from D. P. Johnson in 1984-1987, except for adding copyright and licensing information, as per his request. However, since he originally only provided these disks to me so that I could modify the drivers for my products, he omitted some files that were included with the retail versions of these packages.

Note that I have the source code for edition 27 of SFormat, but unfortunately not for edition 31.


SDisk (release #2) User's Manual.
For OS-9 Level I on the CoCo 2.
(591KB .pdf scanned image)
SDisk3 User's Manual.
For OS-9 Level II on the CoCo 3.
(85KB .pdf scanned image)
DSK image (35T/SS/DD CoCo OS-9 format) of source code and binaries for SDisk edition 18 and SFormat edition 27, and binaries for DescGen and BootFix.
(39KB .zip)
DSK image (35T/SS/DD CoCo OS-9 format) of source code and binaries for SDisk edition 22, and binaries for DescGen, BootFix, ModBuster, and SFormat edition 27.
(42KB .zip)
DSK image (40T/SS/DD CoCo OS-9 format) of source code and binaries for DiskType edition 6, source code for SDisk edition 31, and binaries for SFormat edition 31, DescGen3, and BootFix.
(25KB .zip)
DSK image (35T/SS/DD CoCo OS-9 format) of source code and binaries for SDisk3 edition 12 and DescGenL2 edition 2, and binaries for ModBuster, DiskType edition 6, FLS, Install, and SFormat edition 31.
(32KB .zip)

"FLEX" was a trademark of Technical System Consultants (TSC).
"OS-9" is a registered trademark of Microware LP.
"Radio Shack" and "Color Computer" are trademarks of Tandy Corp.
"MS-DOS" is a trademark of Microsoft Corp.
"CP/M" was a trademark of Digital Research Inc.

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Last revised 2020-Mar-31 21:32 PDT.
Copyright 2020 by David C. Wiens.

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