User`s guide

recognize HD disks just fine. You can even boot off of a HD disk, allowing
plenty of room for System Desk Accessories and such.
There are a few drawbacks: You cannot boot copy-protected software or some
FTA demos. You can't daisy-chain a 5.25" on an HD card. Also, it takes up a
slot, even on the GS.
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From: Benjamin Summers
021- What is a "UniDisk"?
The UniDisk 5.25 was Apple's replacement for the venerable Disk ][. It
featured an updated design, tan color plastic case, a DB-19 cable, and daisy-
chain port on the back to which other drives could be connected. The case color
was later changed to platinum and the drive was rechristened to the "Apple 5.25
Drive".
The UniDisk 3.5 was Apple's first 3.5" drive for the Apple II line. Like
the UniDisk 5.25, it had the DB-19 cable and daisy chain port on back. UniDisk
3.5 was dropped in favor of the Apple Disk 3.5, a different design, at the time
of the launch of the IIgs.
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From: Mitchell Spector
One important difference you forgot to mention: The UniDisk 3.5 was an
"intelligent" drive, whereas the Apple 3.5 was a "dumb" drive. There was a
specialized circuit board inside the UniDisk 3.5 drive which had its own
processor, memory, IWM controller and firmware. This was needed for the //c, in
order for the drive to process data before sending it on to the machine (which
was too slow to do the job by itself). You can easily spot a UniDisk 3.5 as it
matched the snow-white color of the //c and had i
ts access LED and eject button _above_ the disk insert slot (the Apple 3.5 has
them in-line).
______________________________
From: Rubywand
022- What is a "RAM disk"; and, how do I create one on my
IIgs?
A RAM disk is a block of memory which your computer uses like a disk.
To create a RAM disk on your IIgs ...
o- Boot a ProDOS-8 or DOS 3.3 diskette; or, start your computer with no boot and
press CONTROL-Reset to get to the Applesoft prompt.
o- Press OpenApple-Control-ESC (all three keys at once) to get to the Desk
Accessories menu and select "Control Panel".
o- In the Control Panel menu, select "RAM Disk".