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 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 a 360-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 –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 – 2400 bps modems become common; the 16-MHz appears – Compaq releases the first PC – VGA graphics (640  480) appear – Intel introduces the with an integrated co-processor – The Intel Pentium debuts at 60 MHz; the PCI bus appears.

DOS Milestones 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 K 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