Re: History of the IBM PC and challenges for ELKS

["Feher Tamas" <feher.tamas@2fkft.com>]

Hello,

>As part of my talk to my LUG, I'd like to cover a brief history of the
>IBM PC and the challenges of writing an OS for the architecture.

In 1980: rush project at IBM's "backyard" to produce a desktop-fitting personal
microcomputer, loosely based on earlier unsuccessful DisplayWriter. Originally
planned around Motorola 68000 CPU, later converted to 8/16-bit Intel 8088 for
lack of volume chip supply ability by Motorola. Software used was planned to be
CP/M, later Bill Gates sold them MS-DOS v1.00, a facelift version of Q-DOS,
which was a remodelled CP/M. Also there was Xenix, a Unix-clone by M$ and
microCSD-Pascal (or what?), these never became popular. Machine contains BASIC
in bootable EPROM, provided by Microsoft.

In 1981 the model 5150: the original PC, 16-256kB RAM on board, only 5 card
slots, no HDD, a DIN socket to plug in a regular casette recorder (like in
Commodore-64). Floppy drive 5,25" 160/180kB single-sided. MDA video card and
monitor 640*350 pixel, only character-level addressability. Chaplin's figure
used in controversial TV ads to promote the PC, but actually the unit price is
way too high for the people, only companies can buy it. Yet the sales are
ten-fold of the expected.

Lotus 1-2-3, a Visicalc clone spreadsheet appears and propels IBM PC to new
sales heights.

In 1982/83 the model 5160: the PC/XT. Eight card slots, stronger power supply,
256-640kB RAM possible on motherboard, Xebec controller for MFM hard drives
(10MB and up). Floppy drives 320/360kB double-sided introduced (mostly OEM by
Tandon). Option for CGA card/monitor, 640*200 mono or 320*200 four-color
graphics possible. DOS version 2 arrives with XT, able to handle subdirectories.

Hercules card (720*348 pixel mono graphics) introduced by 3rd party
manufacturer, sells like hot cakes, mixes MDA and mono-CGA benefits
EMS introduced, by Lotus-Intel-Microsoft lobby, hardware plug-in cards for the
XT appear.
Epson makes a name as dot-matrix printer supplier.
Novell Copr. ports its Netware LAN server OS from custom hardware to the PC/XT
platform. Huge success. This help ethernet come to PC. Some years later the ISA
ethernet card NE2000 and its sw interface become de facto industry standards.
IBM's reliable and expensive Token-Ring LAN slowly fades from view.

In 1984 the model 5170: The PC/AT. New, cubical system box. Equipped with 16-bit
card slots, backwards compatible with PC/XT 8-bit expansion slots and software.
New 286 CPU, can have 1MB on board, able to address 16MB. Contains clock and
static config memory on board, so no PC/XT-style jumpering necessary to set
drive # anymore. But the config routine is hold on floppy disk, not in on-board
EPROM, that's really silly. New graphics card called EGA, still uses TTL levels
to show 64 colors at 640*350 pixels and crisp 43 lines text. Not hot enough to
finish off cheap Hercules. DOS version 3 arrives with AT, abe to handle 1,2MB
high-density 5,25 inch floppies.

5162: The XT/286. Very rare, has 8-bit card bus and 286 CPU, but cannot address
above 1MB. System case is XT-style.

5155 and a few other silly portable attempts by IBM. Not really suitable ones,
Compaq beats them with a 100% compatible, reverse-engineered, ergonomical unit,
that sells well. Start of the "IBM PC-compatible" clone industry.

IBM and Microsoft decide to develop multitasking, robust  OS/2 for the PC. In
1985, the Windows, originally meant as a temporary solution, is born, all hail
William H. Gates III! The version 1.02 is scrap. That year Intel makes first
80386 chip at 12MHz. Microsoft soon realizes future is 386, while IBM thinks
let's refine for 286 indefinitely. After long feud they split, but both retain
access to existing OS/2 code base.

In 1986, the first 80386 is made, by a clone maker. Clone makers reverse
engineer and formally define the PC/XT and PC/XT expansion buses as ISA-8 and
ISA-16, meaning Industry Standard. Research starts for plug-n-play capability
for ISA-16. They start work towards EISA, a backwards compatible
high-performance 32-bit bus version for 80386 machines and beyond.

First commercial PC sound card AdLib appears. Plain 8-bit mono sound, no midi,
no digital effects; but huge success. Soon Creative Sound Blaster will emerge.

The company Adaptec bring SCSI for the masses to PC world. The 386 PC's more and
more often act as servers in small / medium sized LANs.

In 1987, IBM quits all XT and AT production and introduces Personal System/2
(PS/2) line. New 16/32-bit bus called MCA, cards need external config info from
floppy to work, just plain silly. Bus details confidentals, license available
for lotsa money. The PS/2 line is a huge failure, but IBM takes notice only
after about 4 years and finally scraps MCA. New graphic card introduced in PS/2:
analog levels based VGA, 640*480 at 256 colors. The hard-bound 3,5 inch floppy
appears in PS/2, either 720 or 1440 kB, the smaller one is quickly obsoleted.

These capabilities soon became availabe in clone PCs, VGA chip maker Trident
emerges, followed by at least 20 competing VGA-chip makers. Work starts on
developing ultra-cheap 32-bit bus for VGA cards in clone PCs. The resulting VESA
bus is simply a bunch of lines tied directly to CPU, popular mostly in 486
systems, which arrive after Intel makes first 80486DX chip in 1989. This PC CPU
chip is first to have an integrated numeric unit (FPU), the economy 486SX has it
disabled. SCSI and LAN cards appears in VESA bus format.

Around 1991, work starts on a new 32-bit bus, aimed at replacing the 3-slot
limited VESA connector and the too expensive EISA bus. This becomes the PCI bus
by Intel, an interface commonly used in modern PCs and Unix RISC machines as
well.
Windows 3.0 arrives with full 386-mode support, soon world-conquering Win 3.1
follows.
After WARPAC's fall, Internet soon nets the whole world.

The rest is not really history.

Sincerely: Famas Feher.