Commodore PET
Introduction
The Commodore PET (Personal Electronic Transactor) was a pioneering line of personal computers developed by Commodore International in the late 1970s and early 1980s. As one of the first fully integrated microcomputers, the PET played a significant role in the early personal computer revolution. It was introduced in 1977 and quickly gained popularity in educational and business environments due to its robust design and ease of use. The PET series laid the groundwork for future Commodore computers, such as the Commodore 64 and the VIC-20.
Development and Release
The development of the Commodore PET began in response to the growing interest in microcomputers during the mid-1970s. Commodore, originally a typewriter and calculator company, recognized the potential of the burgeoning computer market. The PET was designed by Chuck Peddle and his team, who had previously worked on the MOS Technology 6502 microprocessor. The 6502 was chosen as the CPU for the PET due to its cost-effectiveness and performance capabilities.
The first model, the PET 2001, was unveiled at the West Coast Computer Faire in April 1977. It featured a distinctive all-in-one design, with a built-in keyboard, monitor, and cassette tape drive. This design was both innovative and practical, making the PET an attractive option for schools and small businesses.
Technical Specifications
The Commodore PET series was known for its distinctive hardware configuration. The original PET 2001 model included a 9-inch monochrome display, a chiclet keyboard, and a built-in cassette drive for data storage. It was powered by the MOS Technology 6502 microprocessor, running at a clock speed of 1 MHz. The PET initially came with 4 KB of RAM, which was later expanded in subsequent models.
Display and Graphics
The PET's display was a monochrome CRT monitor capable of displaying 40 columns by 25 rows of text. The graphics capabilities were limited, as the PET primarily used character-based graphics. However, users could create simple graphics using PETSCII, a variation of the ASCII character set that included graphical symbols.
Memory and Storage
The PET series initially offered 4 KB of RAM, which was expandable to 8 KB or 32 KB in later models. Storage was provided by a built-in cassette tape drive, which was used for loading and saving programs. The cassette drive was eventually replaced by external floppy disk drives, such as the Commodore 2040 and 4040, which offered faster and more reliable data storage.
Input and Output
The PET featured a built-in keyboard, which varied in design across different models. The original PET 2001 had a chiclet-style keyboard, which was later replaced by a more conventional full-travel keyboard in the PET 4000 and 8000 series. The PET also included several I/O ports, such as the IEEE-488 interface, which allowed for the connection of peripherals like printers and disk drives.
Software and Programming
The Commodore PET was shipped with a version of Microsoft BASIC, which was stored in ROM. This made it easy for users to write and execute programs without needing additional software. BASIC was a popular programming language at the time, and its inclusion in the PET contributed to the computer's success in educational settings.
Operating System
The PET did not have a traditional operating system; instead, it relied on a simple monitor program stored in ROM. This program provided basic functionality for loading and saving programs, as well as executing machine code. As the PET evolved, additional software was developed to enhance its capabilities, including word processors, spreadsheets, and educational programs.
Programming Environment
The inclusion of Microsoft BASIC allowed users to write and execute programs directly on the PET. This made it an ideal platform for learning programming and developing custom applications. The PET's memory limitations and character-based graphics encouraged programmers to write efficient code and develop creative solutions to overcome hardware constraints.
Variants and Models
The Commodore PET series underwent several iterations, each offering improvements in hardware and functionality. The main models included the PET 2001, 3000, 4000, and 8000 series.
PET 2001
The original PET 2001 was released in 1977 and featured a 9-inch display, a chiclet keyboard, and a built-in cassette drive. It was available with either 4 KB or 8 KB of RAM. The PET 2001 was well-received for its all-in-one design and affordability.
PET 3000 Series
The PET 3000 series, introduced in 1979, featured an improved keyboard and a larger 12-inch display. The cassette drive was removed, and users were encouraged to use external disk drives for storage. The 3000 series offered models with 8 KB, 16 KB, or 32 KB of RAM.
PET 4000 Series
The PET 4000 series, released in 1980, included further enhancements such as a full-travel keyboard and improved graphics capabilities. The 4000 series models were available with 16 KB or 32 KB of RAM and supported external disk drives for storage.
PET 8000 Series
The PET 8000 series, launched in 1981, represented the pinnacle of the PET line. It featured a larger 12-inch display with 80-column text support, making it suitable for business applications. The 8000 series offered models with 32 KB, 64 KB, or 96 KB of RAM and supported advanced peripherals such as hard drives and network interfaces.
Impact and Legacy
The Commodore PET was instrumental in popularizing personal computers in educational and business environments. Its all-in-one design, affordability, and ease of use made it an attractive option for schools and small businesses. The PET's success laid the foundation for future Commodore computers, such as the VIC-20 and the Commodore 64, which became some of the best-selling computers of all time.
Educational Use
The PET was widely adopted in schools due to its simplicity and durability. It provided an accessible platform for teaching programming and computer literacy. Many educational institutions developed custom software for the PET, which further enhanced its appeal in the classroom.
Business Applications
In addition to its educational use, the PET found success in small business environments. Its reliability and expandability made it suitable for tasks such as word processing, accounting, and inventory management. The PET's IEEE-488 interface allowed for the connection of peripherals, enabling businesses to customize their systems to meet specific needs.
Influence on Future Commodore Products
The success of the PET series influenced the development of future Commodore products. The lessons learned from the PET's design and marketing were applied to subsequent models, such as the VIC-20 and the Commodore 64. These computers built on the PET's legacy, offering improved graphics, sound, and expandability.
Conclusion
The Commodore PET was a groundbreaking personal computer that played a significant role in the early days of the microcomputer revolution. Its innovative design, affordability, and ease of use made it a popular choice for educational and business applications. The PET's legacy lives on in the success of subsequent Commodore computers, which continued to shape the personal computer industry for years to come.