Chapter 8

PC Hardware in the 80s

A Mosaic of Architecture

If the previous chapter focused on the phenomenon of the Commodore 64 and the vibrant home computer market, this chapter will explore in more detail the hardware that characterized the personal computers of the 1980s, a period of great innovation and technological diversification. We will examine the fundamental components that made up a PC, from motherboards to storage devices, highlighting the differences between the various dominant platforms of the time, such as the IBM PC and its compatibles, the Apple Macintosh, and more home/multimedia-oriented machines such as the Commodore Amiga and the Atari ST.

8.1 The Motherboard and the Microprocessor:
The Beating Heart of the System

The motherboard represented the backbone of the personal computer, the main printed circuit board that housed the microprocessor, memory, supporting chipsets and expansion slots for additional cards. The microprocessor was the "brain" of the system, responsible for executing software instructions. The 1980s saw a rapid evolution of microprocessors:

• IBM PC and Compatibles: The first generation IBM PC (1981) used the Intel 8088 microprocessor, a 16-bit chip with an 8-bit data bus, operating at a clock speed of 4.77 MHz.
• This processor, while not the most powerful of the time, it became the de facto standard for the PC market thanks to IBM's success. Subsequently, the introduction of the Intel 80286 (in the 1984 IBM PC AT) and the Intel 80386 (in the 1986 Compaq Deskpro 386) led to a significant increase in computing power and memory addressing capacity. Processor clock speeds increased progressively throughout the decade, reaching 16, 20, and even 33 MHz for 80386 models in the late 1980s.
• Apple Macintosh: The original Macintosh (1984) was based on the Motorola 68000 microprocessor, a 16/32-bit chip that offered superior performance to the Intel 8088 in many operations, especially in handling graphics. Subsequent Macintosh models continued to use the Motorola 68K processor family, such as the 68020 and 68030, offering increasing power to support increasingly complex graphical user interfaces and applications.
• Commodore Amiga: The Amiga (1985) also used the Motorola 68000 microprocessor, combined with custom graphics and sound chipsets that gave it advanced multimedia capabilities for its time.
• Atari ST: The Atari ST (1985) was also based on the Motorola 68000 , positioning itself as a direct competitor to the Amiga.

The chipset on the motherboard played a crucial role in coordinating communications between the microprocessor, memory, and other peripherals. In early PCs, the chipset consisted of several discrete chips, but as the technology evolved, its functionality was integrated into fewer and fewer components, improving efficiency and reducing costs.

8.2 RAM Memory:
The "Workbench" of the Computer

The Random Access Memory (RAM) was the main memory of the computer, used to temporarily store data and instructions of running programs. In the 1980s, the amount of RAM in PCs varied greatly depending on the model and price. The first IBM PCs had a base configuration of only 64 KB of RAM, expandable to 640 KB (the upper limit imposed by the original architecture). The original Macintosh had 128 KB of RAM, which was later increased in later models. The Amiga and Atari ST often had 512KB or 1MB of RAM, reflecting their greater emphasis on graphics and multimedia capabilities.

RAM was typically provided in the form of chips DIP (Dual In-line Package) , which were inserted into special sockets on the motherboard. Towards the end of the 1980s, SIMM (Single In-line Memory Module) modules began to spread, which allowed larger amounts of memory to be installed more easily. The amount of available RAM directly affected the computer's ability to run complex software and handle multiple applications at the same time.

8.3 Graphics Cards and Monitors:
Viewing Information

The graphics cards (or video cards) were responsible for generating the video signal sent to the monitor. In the 1980s, there was a rapid evolution of PC graphics standards:

• MDA (Monochrome Display Adapter): The initial standard for the IBM PC, it offered only monochrome text (usually green or amber) with good sharpness for text-based business applications.

• CGA (Color Graphics Adapter): It introduced the possibility of displaying color graphics, with a resolution of 320x200 pixels and 4 colors, or 640x200 pixels in black and white. The image quality was limited, but it paved the way for color gaming on PCs.
• EGA (Enhanced Graphics Adapter): It offered a higher resolution (640x350 pixels) and a 16-color palette, significantly improving graphics quality compared to CGA and becoming a standard for professional applications and some games.
• VGA (Video Graphics Array): Introduced with the IBM PS/2 in 1987, VGA became the dominant standard in the late 1980s and beyond. It offered a resolution of 640x480 pixels with 16 colors, or 320x200 pixels with 256 colors, providing significantly higher graphics quality.

The monitors used with PCs in the 1980s were mainly of the CRT (Cathode Ray Tube) type. They could be monochrome or color, depending on the graphics card used. Monitor quality and resolution were important factors in text clarity and graphics rendering.

The Macintosh was notable for its integrated graphical interface and monitors that often offered higher resolution than PC standards of the time. The Amiga and Atari ST boasted custom graphics chipsets that allowed them to display more colors and handle sprites and animations more efficiently, making them well-suited for gaming and multimedia applications.

8.4 Sound Cards and Speakers:
Sound in the PC World

The audio capabilities of early IBM PCs were extremely limited, often reduced to simple "beeps" emitted from the internal speaker. However, in the mid-1980s, the first dedicated sound cards emerged and significantly improved the sound experience on PCs.

• AdLib: One of the first successful sound cards for PCs, it used a Yamaha chip for FM sound synthesis, offering the ability to create more complex music and sound effects in games.
• Sound Blaster: Introduced by Creative Labs in 1989, Sound Blaster quickly became the de facto standard for PC sound cards. It supported FM synthesis, digital sample playback, and offered AdLib card compatibility, making it an essential for PC gamers.

The Macintosh, Amiga, and Atari ST had more advanced sound capabilities built directly into the motherboard, often with dedicated sound chips that allowed digitized (sampled) sounds to be played in higher quality than early PCs with sound cards. External speakers ​​ were required to listen to audio generated by sound cards or integrated audio circuits.

8.5 Storage Devices:
Floppy Disks, Hard Disks and Magnetic Tapes

Personal computers of the 1980s used several types of devices for storing data and programs:

• Floppy Disk Drive: The floppy disk was the most common removable storage medium. By the early 1980s, 5.25-inch floppy disks were the standard, with capacities ranging from a few hundred kilobytes to 1.2 megabytes (for high-density disks introduced later).
• Towards the end of the decade, 3.5-inch floppy disks, smaller, more robust and with greater capacity (typically 1.44 megabytes), began to replace the 5.25-inch ones. Floppy disks were used for software distribution, file transfer, and data backup.
• Hard Disk Drives: Hard disks (hard disks) offered much greater storage capacity than floppy disks and faster access times. Initially expensive and not always found in low-end PCs, hard drives became increasingly accessible and widespread throughout the 1980s. Hard disk capacities progressively increased, going from a few megabytes to tens and then hundreds of megabytes by the end of the decade. The presence of a hard disk made using the PC much more convenient, allowing the operating system and applications to be installed directly on the disk and files to be accessed quickly.
• Tape Drives: Magnetic tape drives were primarily used for data backup, offering a cost-effective solution for storing large amounts of information, albeit with sequential access.