Apple III
 | |
| Apple III personal computer | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Business Computer |
| Released | May 1980 |
| Discontinued | April 24, 1984 |
| Intro price | US$4,340 (base, 1980) |
| CPU | Synertek 6502A @ 2 MHz |
| Memory | 128 KB RAM (expandable to 512 KB) |
| Storage | Built-in 140 KB 5.25" floppy drive, optional external floppy and ProFile hard disk |
| Display | 24 lines × 80 columns text; 560×192 graphics (monochrome) |
| Sound | 1-bit beeper |
| Dimensions | 12 cm × 40 cm × 45 cm |
| Weight | 10.9 kg (24 lb) |
| OS / Firmware | Apple SOS (Sophisticated Operating System), Apple III BASIC |
| Successor | Apple III Plus |
| Codename | Sara |
| Model no. | A3S1, A3S2, A3S3 |
The Apple III was Apple Computer, Inc.'s first business-oriented personal computer, introduced in May 1980 as the intended successor to the successful Apple II Plus. Designed for professional and corporate users, it featured a new operating system, more memory, and advanced display capabilities, but suffered from reliability issues that impacted its commercial success.
Architecture and Processor
[edit | edit source]The Apple III utilised a Synertek 6502A microprocessor running at 2 MHz—double the clock speed of the Apple II series. The system architecture was designed to be compatible at a hardware level with Apple II software (in a special emulation mode), but primarily targeted new business applications written for its advanced feature set.
Key architectural features included:
- Synertek 6502A CPU @ 2 MHz
- Custom Apple-designed logic for memory management and video
- Hardware support for 80-column text and high-resolution monochrome graphics
- Separate character generator ROM for business-oriented text display
Memory and Storage
[edit | edit source]The Apple III shipped standard with 128 KB of RAM, expandable up to 512 KB via internal memory boards—significantly more than its predecessor. ROM included the Apple III BASIC interpreter and system firmware.
Storage options:
- Built-in 140 KB 5.25" floppy disk drive (single-sided, single-density)
- Support for up to three external floppy drives
- Optional ProFile hard disk drive (5 MB) via interface card
Display and Graphics
[edit | edit source]The Apple III introduced advanced display capabilities for its time:
- Text modes: 24 lines × 80 columns (business standard), 24 × 40 mode for Apple II compatibility
- Graphics modes: 560×192 pixels (monochrome), 280×192 (6 colours, Apple II compatible)
- Programmable character generator for custom fonts and internationalisation
The 80-column text and high-resolution graphics made the Apple III suitable for word processing, spreadsheets, and business graphics.
Sound Capabilities
[edit | edit source]Sound on the Apple III was basic, provided by a 1-bit beeper controlled directly by the CPU. This was similar to the Apple II and limited to simple tones and alerts.
Input/Output and Expansion
[edit | edit source]The Apple III offered a range of I/O and expansion options:
- Serial ports: Two RS-232C-compatible DB-25 connectors for printers and modems
- Parallel port: Optional via interface card
- Video output: Composite video for monochrome or colour monitors
- Keyboard: Full-stroke, 74-key keyboard with numeric keypad
- Expansion slots: Four internal slots compatible with most Apple II peripheral cards
- External drive port: For additional floppy or ProFile hard disk
These features allowed the Apple III to connect to a variety of business peripherals and expand its capabilities as needed.
Gallery
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Apple III keyboard with numeric keypad -
Apple III internal view (logic board and drive)
Related Pages
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