Emulator
DOSBox emulates the familiar command-line
interface of DOS.
An emulator duplicates (provides an emula-
tion of) the functions of one system using a
different system, so that the second system
behaves like (and appears to be) the first sys-
tem. This focus on exact reproduction of ex-
ternal behavior is in contrast to some other
forms of computer simulation, which can con-
cern an abstract model of the system being
simulated.
Emulators in computer
science
Basilisk 2 emulates a Macintosh 68k using in-
terpretation code and dynamic recompilation.
Emulation refers to the ability of a computer
program or electronic device to imitate an-
other program or device. Many printers, for
example, are designed to emulate Hewlett-
Packard LaserJet printers because so much
software is written for HP printers. By emu-
lating an HP printer, a printer can work with
any software written for a real HP printer.
Emulation "tricks" the running software into
believing that a device is really some other
device.
A hardware emulator
is an emulator
which takes the form of a hardware device.
Examples includes the DOS-compatible card
installed in some old-world Macintoshes like
Centris 610 or Performa 630 that allowed
them to run PC programs and FPGA-based
hardware emulators.
In a theoretical sense, the Church-Turing
thesis implies that any operating environ-
ment can be emulated within any other.
However, in practice, it can be quite difficult,
particularly when the exact behavior of the
system to be emulated is not documented
and has to be deduced through reverse en-
gineering. It also says nothing about timing
constraints; if the emulator does not perform
as quickly as the original hardware, the emu-
lated software may run much more slowly
than it would have on the original hardware,
possibly triggering time interrupts to alter
performance.
Emulation in
preservation
Emulation is a strategy in digital preserva-
tion to combat obsolescence. Emulation fo-
cuses on recreating an original computer en-
vironment, which can be time-consum