BKSYBIOS.RVW 940317 Addison-Wesley Publishing Company Heather Rignanesi, Marketing, x340, 73171.657@Compuserve.com P.O. Box 520 26 Prince Andrew Place Don Mills, Ontario M3C 2T8 416-447-5101 fax: 416-443-0948 or Tiffany Moore, Publicity tiffanym@aw.com Bob Donegon bobd@aw.com John Wait, Editor, Corporate and Professional Publishing johnw@aw.com Tom Stone, Editor, Higher Education Division tomsto@aw.com Philip Sutherland, Schulman Series 74640.2405@compuserve.com 1 Jacob Way Reading, MA 01867-9984 800-822-6339 617-944-3700 Fax: (617) 944-7273 5851 Guion Road Indianapolis, IN 46254 800-447-2226 "System BIOS for IBM PCs, Compatibles, and EISA Computers", Second Edition, Phoenix Technologies Ltd., 1991, 0-201-57760-7, U$29.95/C$38.95. Early microcomputers, like early computers, had no operating system. Then came the proprietary micros aimed at the home or business market rather than the hobbyists. These systems, built by single companies, could have the operating system built in by having it programmed in ROM. Then came computers which allowed you to change the operating system. The easiest way to do this was to store the operating system on a storage medium like a disk. Disks are much easier to modify than ROM chips. However, you still needed to have a minimal amount of programming built in (and preferably enough to load the rest of the operating system off the disk). On the IBM PC, this was referred to as the Basic Input/Output System or BIOS. The Intel CPU at the heart of the PC was designed to work well with a system of interrupts, and so the PC BIOS was designed with these interrupts in mind. It sets up an interrupt table with a series of sub routines dealing with video (such as the setting of cursor position), disk (such as reading disk status), port (such as receiving a character), and keyboard (such as storing key data) services. It also starts a routine which loads bootstrap programming from the disk. An additional benefit of this architecture was that, within limits, certain changes could be made to the hardware. Ordinarily such changes would require new versions of the operating system, but with the BIOS design, only the BIOS would have to be modified. As those with UNIX and OS/2 systems hit by the Stoned or Michelangelo virus have found to their chagrin, the BIOS is a complete, though limited, operating system. It also forms, in a sense, the microkernel of the MS-DOS operating system, and therefore, for system level programming, it is pretty much "required reading" for MS-DOS programmers. This reference is written by Phoenix, one of the major BIOS manufacturers. Do be aware that some minor differences may be present in other BIOS versions. copyright, Robert M. Slade, 1994 BKSYBIOS.RVW 940317 ============== Vancouver ROBERTS@decus.ca | Oh, wow, far out man! Institute for Robert_Slade@sfu.ca | Says my PC is now Stoned! Research into rslade@cue.bc.ca | 1.2s lose files User p1@CyberStore.ca | Security Canada V7K 2G6 | - virus haiku