petSD+ Operation

Both the internal and external versions of petSD+ can be controlled from the PET/CBM using native DOS (4.0) commands, but usage is much easier if a DOS Wedge is loaded. (DOS 2.0 can also be used, but I have not done this as I only have a DOS 4.0 machine available.) For the additional features available if the LCD option is fitted, see the next page.

At its simplest, petSD+ acts like a Commodore floppy disk system with a single drive installed, it can be used instead of, and alongside, vintage floppy disk drives. A complete description of how to use a Commodore disk is beyond the scope of this page, for full details, see the Commodore Disk System manuals on my PET Documents page.

This page gives brief summary of the most common BASIC commands used to save and load programs and files from petSD+. Commands shown on this page are compatible with Commodore BASIC 4, the corresponding DOS wedge commands are also given. In many cases, there is more than one way to achieve the same result. The petSD+ firmware (NODISKEMU) also includes enhancements from sd2iec which provide a number of features beyond those present in Commodore DOS (see this page for details).

As noted on my Disk Commands page, at the lowest level, the syntax used to communicate with a disk device is very much like file I/O operations used in other systems, e.g., "opening" the device, doing some operation and "closing" the device. By the time that BASIC 4.0 was released, many of the low level operations were available using BASIC keywords such as DLOAD, but sending other low level commands from the computer to the Disk Controller was still performed using the Command Channel (#15).

In the examples shown, the default petSD+ device address (#8) is assumed and the text is in lower case mode as used on my CBM 8096.

petSD+ Enhancements