Catalyst will take full advantage of the QC hard disk provided that minor modifications to the .CATALYST device driver are made. A partial discussion of this modification is located on page 4-9 of the QC manual. Below are additional steps that must be completed in order to insure complete compatibility. PREREQUISITES: Catalyst for the Apple III Special DCB values in the .CATALYST device driver are required in order for the Catalyst for the Apple III to take advantage of this feature. The first 6 bytes (0-5) are device specific and can be determined by following the instructions on page 4-9 of the QC manual. The bytes are assigned as follows: BYTE ASSIGNMENT 0 Slot Number 1 Unit Number 2 Device Type 3 Device Subtype 4 Manufacturer ID (low byte) 5 Manufacturer ID ( high byte) Bytes 6-17 are checksum bytes. Their values must correspond to the following: 0 1 2 3 4 5 6 7 8 9 A B C D E F 0x 0S UU TT ST MM MM 00 8F 97 8A 91 93 23 17 17 F6 1x 00 B8 EXAMPLE OF THE ".CATALYST "DRIVER DCB USING THE QC-10 DEVICE ".Q1": 00 00 F1 AA 23 00 00 8F 97 8A 91 93 23 17 17 F6 00 B8 NOTE: Apple Computer Inc. is not responsible for the contents of this article.