Apple Macintosh LC 630 DOS - Manual (Page 76)

Setting shared memory
You can install a 72-pin SIMM (memory module) on the DOS-compatible
card in your computer to give the card up to 32 MB of RAM for its exclusive
use. When no SIMM is installed, the card uses a portion of the RAM
installed in your Macintosh.
If your computer came with a SIMM already installed on the
DOS-compatible card, you cannot share memory between the Mac OS
and the PC environment. The PC uses the memory installed on the
DOS-compatible card exclusively. The shared memory options in the
PC Setup control panel will be dimmed (unavailable). See the Technical
Specifications booklet to determine whether your computer contains a
SIMM installed on the DOS-compatible card.
m Choose the amount of memory you want for your PC in the RAM pop-up menu.
In the RAM pop-up menu, a small square (M) shows the RAM that the PC is
currently using and a bullet (•) indicates how much RAM you assigned.
When the Macintosh starts up, it claims RAM for its own use before it sets
aside RAM for the PC. If the PC has less RAM than you installed, turn off
the Mac OS RAM disk (if you’re using one) in the Memory control panel.
You may also need to lower the disk cache size in the Memory control panel
to 128K or less.
Memory changes take place when you restart the Macintosh.
IMPORTANT Memory that you set aside for the PC environment is not
available to the Mac OS. To make this memory available, you must turn off
the PC (click the Off button at the top of the PC Setup control panel) and
restart the Macintosh.
65 Configuring the PC Environment