A Short History of the PC

Prolog

• Before the IBM, there were many PC vendors.– These were typically garage-shop start-ups with shaky

financing.– The big names were Radio Shack and Apple.

• Early personal computers were crude.– CPUs were 8-bit, usually and 8080 or Z80.– Storage was usually on audio cassette tape as diskette

drives were expensive.– Monitors were TV sets with a maximum of 64 characters

per line.– Printers were very expensive and often were upper-

case only.– The big applications were WordStar and VisiCalc.

IBM PC – 1981

• CPU – Intel 8088– 16-bit CPU, 8-bit I/O, 4.77 MHz clock– 8-bit Industry Standard Architecture (ISA) expansion bus.– 16 K to 64 K RAM (up to 640 K with a RAM expansion card)

• ROM BASIC• Operating systems

– PC-DOS ($40)– CP/M ($450)– UCSD p-System ($550)

• $1265 (plus monitor, video controller, operating system, serial port, floppy disk, and printer)

1981 IBM PC Features

• Displays– “High-resolution” character-only (80 per line) with a

monochrome monitor.– Low-resolution graphics controller with a color display.

• RAM cards were needed to expand memory beyond 64K.

• Diskette drives held of 360 Kbytes.• Modems had speeds of 100 to 300 bps.• Printers used matrix-impact technology and

ribbons.

1981 IBM PC Accessories

IBM PC Open Architecture

• IBM published its hardware interface specifications.– This allowed other companies to develop expansion

cards, keyboards, mice, etc.

• IBM decided that they would profit only from the hardware.– All software was developed by other companies.

• IBM published its BIOS specifications.– As a result other companies reversed-engineered the

BIOS, which allowed PC clones into the market.

• IBM allowed Microsoft to sell DOS to others.

MS-DOS Screen

MS-DOS

• The basic operating-system commands were in ROM so you could swap your program diskette with one containing data.

• DOS contained few services. For example, an editor had to know how to control your printer.

• Users had to configure peripherals (e.g., modems, ports, and printers) by editing control files, such as autoexec.bat and config.sys.

• The simple software of the day easily fit on a360-K diskette.

IBM XT – 1983

• CPU – Intel 8088– 16-bit processor, 8-bit I/O– 4.77 MHz clock– 8-bit ISA bus– 256 K or 640 K RAM in 36 DIP sockets

• 360K, 5-¼” diskette (720K, 3-½” optional)• 10 or 20 Mbyte hard disk• $5000 (with a 10-MB disk)• Other manufacturers began to enter the PC

market.

IBM AT – 1984

• CPU – Intel 80286– 16-bit processor, 16-bit I/O– 6 or 8 MHz clock– 16-bit ISA bus– 512 K on motherboard, 16M maximum

• 1.2M, 5-¼” diskette (1.44M, 3-½” optional)

• 20 or 30 Mbyte hard disk

• EGA graphics

• $6000 with a 20 Mbyte disk

Hardware Milestones

• 1982 – Compaq “Portable” (28 lbs., ac power)• 1984 – HP introduces the laser printer.• 1985 – 2400 bps modems become common;

the 16-MHz 80386 appears.• 1986 – Compaq releases the first 80386 PC.• 1987 – VGA graphics (640480) appear.• 1990 – Intel introduces the 80486 with an

integrated co-processor.• 1993 – The Intel Pentium debuts at 60 MHz;

the PCI bus appears.

DOS Milestones

• 1981 - DOS 1 (purchased from Seattle Computing for $50,000)

• 1983 – DOS 2 (subdirectory and 10-MB hard disk support)• 1984 – DOS 3 (1.2-MB diskette and 32-MB hard disk

support)• 1988 – DOS 4 (too buggy to be popular)• 1991 – DOS 5 (allowed the use of 640-1024K RAM and

larger disks, added a disk cache and undelete)• 1993 – DOS 6 (disk compression and defragging, better

memory management)

Windows 1.0 Screen

MS Windows Milestones

• 1985 – Windows 1.0 (a DOS shell, crude and slow)• 1987 – Windows 2.0 (icons, overlapping windows)• 1990 – Windows 3.0 (16 colors, new file manager, the first

successful version)• 1992 – Windows 3.1 (drag-and-drop, better integration)• 1995 – Windows 95 (long filenames, dial-up networking)• 1998 – Windows 98 (USB support, Internet Explorer 4

built- in)• 2001 – Windows XP (32-bit architecture, DOS

independence)

Epilog