Specifications

CHAPTER 4
Software
40 System Software
System Software 4
The Macintosh LC 520 computer requires System 7.1 or a later version of system software.
The disk labeled “Install Me First” includes a system enabler file that contains the
resources the system needs to start up and initialize the Macintosh LC 520 computer.
The system disk includes an Installer application to install the control panels for the new
features of the machine.
System Enabler 4
Starting with the international release of System 7.1, each reference release of the
Macintosh system software supports a new startup extension, the system enabler. The
system enabler is a software resource that is able to perform the correct startup process
for one or more Macintosh computers.
As soon as the system software on disk takes over the startup process, it searches for all
system enablers that can start up the particular machine. Each system enabler contains a
resource that specifies which computers it is able to start up and the time and date of its
creation. If the system software finds more than one enabler for the particular computer,
it passes control to the one with the most recent time and date.
In general, the system enabler included in each reference release of system software is
able to start up all previous computers. The system enabler that accompanies a later
computer will be able to start up that computer, possibly using resources from the
previous reference release.
Booting From a CD-ROM 4
The Macintosh LC 520 computer can start up (boot) from a built-in CD-ROM drive.
Starting up in this fashion is not recommended, because the system software was not
designed to operate from a locked storage device—one that the software can’t write to.
The system software that Apple Computer uses on the system CD-ROM includes only
one control panel file—for setting the startup disk—along with Installer software to
install the system onto a hard disk. Developers may wish to use a similar arrangement to
distribute bulky software.
New Control Panels 4
The system software for the Macintosh LC 520 computer includes new control panels for
the sound level and the screen brightness and contrast.