ephraim@wang.UUCP (pri=8 Ephraim Vishniac x76659 ms1459) (02/24/86)
Here's a summary of how to make your HFS-formatted hard disk launch relatively quickly from a floppy. 1. Get a copy of the HD20 startup disk. It should have finder 5.1, system 3.0, and a system file called "Hard Disk 20" on it. 2. Booting with this disk will let you format most hard disks as HFS volumes just by pulling down "Erase Disk" in the finder. Do it, then copy the system files (and anything else you want) onto the hard disk. 3. Paste your hard disk driver into either the system file or the Hard Disk 20 file on the startup floppy. 4. Write a little piece of code that does the following: Saves registers Loads, detaches, and calls PTCH resource number 3. Opens your disk driver, creates drive queue entry, etc. Makes itself purgable Restores registers and returns. 5. Open the Hard Disk 20 file with ResEdit. Renumber PTCH 2 '.Sony' to be PTCH 3 instead. Paste in your own code as PTCH 2. 6. Boot with your hacked floppy. It will open your driver and transfer control to your hard disk during system init. The floppy will eject automatically. Warnings: This won't work if your disk is formatted "flat". _MountVol consumes stack space proportional to directory size for flat volumes. On a hard disk, the directory is usually large enough to blow out the stack if you try this during system init. This will only work with the 64K ROMs, because the patches (PTCH resources) don't run if they aren't needed. Renaming the .Sony patch and calling it from your code is important. If you don't do this, you won't be able to initialize floppy disks! How it works: During startup, the two PTCH resources (105 and 117) are executed. PTCH 105 (the interesting one) installs a bunch of its own patches, then opens the resource file "Hard Disk 20" and looks for PTCH's 0, 1, and 2. It executes them (if found), then looks around for a non-floppy drive (drive number >2) to transfer control to. Substituting your own patch for PTCH 2 lets you set up your drive in time to get in on this act. It does a _MountVol on any such drive it finds, then checks it for system and finder files. If these are found, it swaps systems, changes the default volume, and ejects the startup floppy. Disassembling PTCH 105 in the system file reveals a number of interesting things, such as how to find the System Folder on an HFS disk (exhaustive search is *not* the answer). I can post more details if anyone's interested. Ephraim