This invention relates generally to personal computers, and particularly to a personal computer having a removable computer peripheral.
Personal computer systems in general and IBM personal computers in particular have attained widespread use for providing computer power to many segments of today's modern society. Personal computer systems can usually be defined as a desk top, floor standing, or portable microcomputer that consists of a system unit having a single system processor and associated volatile and non-volatile memory, a display monitor, a keyboard, one or more diskette drives, a fixed disk storage, and an optional printer. One of the distinguishing characteristics of these systems is the use of a motherboard, or system planar, to electrically connect these components together. These systems are designed primarily to give independent computing capability to a single user and are inexpensively priced for purchase by individuals or small businesses. Examples of such personal computer systems are IBM's PERSONAL COMPUTER XT and AT and IBM's PERSONAL SYSTEM/2 Models 25, 30, 35, 40, 50, 55, 56, 57, 60, 65, 70, 80, 90, and 95.
These systems can be classified into two general families. The first family, usually referred to as Family I Models, use a bus architecture exemplified by the IBM PERSONAL COMPUTER AT and other "IBM compatible" machines. The second family, referred to as Family II Models, use IBM's MICRO CHANNEL bus architecture exemplified by IBM's PERSONAL SYSTEM/2 Models 50 through 80. Many Family I models have used the popular INTEL 8088 or 8086 microprocessor as the system processor. These processors have the ability to address one megabyte of memory. Certain Family I and most Family II models typically use the high speed INTEL 80286, 80386, 80486, and Pentium microprocessors which can operate in a real mode to emulate the slower speed INTEL 8086 microprocessor or a protected mode which extends the addressing range from 1 megabyte to 4 Gigabytes for some models. In essence, the real mode feature of the 80286, 80386, and 80486 processors provide hardware compatibility with software written for the 8086 and 8088 microprocessors.
PCs are particularly useful in a client-server environment where at least one PC system can be used as a server and other units, connected to the server, share the server's resources. Servers must often meet certain security requirements, possibly to notify the user of tampering. An unauthorized user may system may tamper with a system while running the authorized user's operating system (and application programs) and the authorized user may not be notified of the tampering until the next time the system is either powered off and then on or rebooted.