The IBM Personal Computer XT (eXtended Technology), often simply called the IBM XT, was a significant personal computer released by IBM in October 1983. It was a direct successor to the original IBM PC (released in 1981) and built upon its architecture, but with key improvements aimed primarily at the business market.
Here’s a breakdown of its key features, significance, and legacy:
Key Features & Specifications:
- Processor:
- CPU: Intel 8088
- Clock Speed: 4.77 MHz
- (This was the same processor and speed as the original IBM PC, meaning it wasn’t faster in terms of raw CPU power, but the overall system was more capable).
- Memory:
- Standard RAM: Typically 128KB or 256KB, though some configurations started at 64KB.
- Maximum RAM: Expandable to 640KB on the motherboard (the maximum addressable by MS-DOS without special memory managers).
- Storage:
- Hard Drive: This was the most significant new feature. The XT was the first IBM PC to come standard with an integrated hard drive.
- Initial models featured a 10 MB (megabyte) hard drive. Later models offered 20 MB drives.
- This revolutionized personal computing, moving away from floppy-only systems to more permanent and larger-capacity storage, essential for business applications and larger software suites.
- Floppy Drive: Usually one 5.25-inch double-sided, double-density (360 KB) floppy disk drive. A second floppy drive could be installed in place of a second hard drive.
- Hard Drive: This was the most significant new feature. The XT was the first IBM PC to come standard with an integrated hard drive.
- Expansion Slots:
- 8-bit ISA Slots: The XT provided eight 8-bit ISA (Industry Standard Architecture) expansion slots. This was an increase from the five slots in the original IBM PC and a crucial feature, allowing users to add various peripheral cards (graphics cards, sound cards, network cards, memory expansion, I/O ports).
- Operating System:
- IBM PC DOS 2.0 (and later versions): This version of DOS introduced support for hard drives and a hierarchical file system (subdirectories), which was essential for managing the larger storage capacity of the hard drive.
- Input/Output:
- Keyboard: Famous for its robust and tactile “XT keyboard” (often an IBM Model F variant), which had an excellent feel but a somewhat idiosyncratic layout (e.g., function keys on the left side).
- Video: Like the original PC, video capabilities were provided via expansion cards (e.g., IBM Monochrome Display Adapter for text, or IBM Color Graphics Adapter for basic color graphics).
- Ports: Serial and parallel ports were typically added via expansion cards.
- Power Supply: A more robust power supply (130W) than the original PC to handle the hard drive and more expansion cards.
Significance and Legacy:
- Standardization of the PC Architecture: The XT further solidified the IBM PC architecture as the industry standard. Its design was widely copied by “clone” manufacturers, leading to the vast market of IBM PC compatible computers.
- Hard Drive Adoption: By making a hard drive standard, the XT accelerated the adoption of hard drives in personal computers, fundamentally changing how software was developed and used. It enabled larger, more complex applications and permanent data storage for business users.
- Business Workhorse: The XT became a staple in offices and businesses, serving as a reliable workhorse for word processing, spreadsheets (like Lotus 1-2-3), database management, and early business applications.
- “XT Class” Machines: The term “XT class” became synonymous with computers featuring an Intel 8088 or 8086 processor, an 8-bit ISA bus, and a clock speed around 4.77 MHz, even if they weren’t manufactured by IBM.
- Foundation for Future PCs: The XT’s design principles, particularly the expansion bus and the role of DOS, laid the groundwork for future generations of personal computers, including the AT (Advanced Technology) and beyond.
In essence, the IBM PC XT was not a revolutionary speed demon, but its integration of a hard drive and enhanced expansion capabilities made it a powerful and pivotal machine that transformed personal computers from mere hobbyist devices into indispensable tools for businesses and professionals.