AppleWin/help/ddi-intro.html
2006-07-08 15:41:03 +00:00

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1.5 KiB
HTML

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>Introduction to Disk Images</title>
</head>
<body style="background-color: rgb(255, 255, 255); font-family: verdana;" alink="#008000" link="#008000" vlink="#008000">
<h2 style="color: rgb(0, 128, 0);">Introduction
to Disk
Images</h2>
<hr size="4">
<p>Everyone who once used an
Apple II and now
uses an IBM-compatible PC has the same problem:&nbsp; How can you
make
the PC read Apple floppy disks? Unfortunately, without special
hardware, you can't. </p>
<p>Floppy disks are analog
devices, much like
cassette tapes. For a computer to store digital data on a floppy
disk, it must "encode" the data into an analog format.
The Apple II used a method of encoding called Group Code
Recording (GCR), while IBM-compatible PC's use the much more
standard Modified Frequency Modulation (MFM) encoding. Since this
is all done in hardware and cannot be bypassed, it is not
possible for a PC program to "reprogram" the floppy
drive in such a way that it could read Apple-formatted floppy diskettes. </p>
<p>Therefore, instead of reading
and writing
disks directly, AppleWin uses disk images. A disk image is a
single file, which you can store on your hard drive or on a PC
floppy diskette, which contains all of the data from an entire Apple
diskette. AppleWin treats an image exactly as if it were a real
floppy disk. </p>
</body>
</html>