IBM XT 5160 Technical Reference page 6

Preface
This publication describes the various components of the IBM
Personal Computer XT and IBM Portable Personal Computer;
and the interaction of each.
The information in this publication is for reference, and is
intended for hardware and program designers, programmers,
engineers, and anyone else with a knowledge of electronics
and/or programming who needs to understand the design and
operation of the IBM Personal Computer XT or IBM Portable
Personal Computer.
This publication consists of two parts: a system manual and an
options and adapters manual.
.The system manual is divided into the following sections:
Section 1, "System Board", discusses the component layout,
circuitry, and function of the system board.
Section 2, "Coprocessor", describes the Intel 8087
coprocessor and provides programming and hardware
interface information.
Section 3, "Power Supply", provides electrical input/output
specifications as well as theory of operation for both the IBM
Personal Computer XT power supply and the IBM Portable
Personal Computer power supply.
Section 4, "Keyboard", discusses the hardware makeup,
function, and layouts of the IBM Personal Computer XT
83-keyand lOl/102-key keyboards and the IBM Portable
Personal Computer keyboard. In addition, keyboardencod-
ing and usage is discussed.
Section 5, "System Bios", describes the basic input/output
system and its use. This section also contains the software
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