Specifications

CHAPTER 1
Introduction
6 Power On and Off
Video RAM 1
The Macintosh LC 520 computer comes with 512 KB of VRAM and a socket for a SIMM
with an additional 256 KB of VRAM. The VRAM expansion SIMM is the same 68-pin
SIMM used with the Macintosh LC III and Macintosh Quadra computers. It requires
VRAM devices with access times of 80 ns or less.
The basic 512 KB VRAM provides up to 8 bits per pixel; the screen displays up to 256
colors, software-selectable from a range of 16 million. With the VRAM SIMM installed,
the Macintosh LC 520 has 768 KB of VRAM, allowing it to display up to 16 bits per pixel,
which provides 32,768 colors. If the VRAM SIMM has been installed, the user can set
the display to 16 bits per pixel by opening the Monitors control panel and choosing
Thousands.
Table 1-1 lists the bits per pixel and numbers of colors available for the different sizes
of VRAM.
Power On and Off 1
The master power switch on the back of the computer must be in the On position for the
computer to operate. As long as the master power switch is in the On position, the user
can turn the power off and on by pressing the power key on the keyboard.
Note
If you plan to leave the computer turned off for an extended period of
time, you should flip the master power switch to the Off position. ◆
If the user attempts to turn off the computer—using either the power key or the Shut
Down menu item—while files are still open, the system displays an alert box warning the
user that files are open and should be closed to avoid loss of data. If the user turns off the
master power switch while the computer is operating, the computer shuts off
immediately, without performing the safe shutdown.
Table 1-1 VRAM size and number of colors
VRAM size Bits per pixel Number of colors
512 KB 1, 2, 4, or 8 2, 4, 16, or 256
768 KB 1, 2, 4, 8, or 16 2, 4, 16, 256, or 32,768
(only 15 bits are used)