IBM Vintage Computers and Mainframes

IBM Vintage Computers and Mainframes: What to Know

IBM vintage PC and mainframe computing components can be fun to collect if you're interested in working with old equipment. Certain industrial processes still use vintage big-iron keypunch equipment, too, which makes some of these pieces useful in today's manufacturing environment, and the large, simple systems are also a good starting point for learning computer construction. Discover your own reason to purchase vintage, preowned IBM equipment from eBay.

The peripheral-component-interconnect (PCI) slots on vintage IBM computers are compatible with conventional PCI cards. You can insert the card into the computer by holding it with both hands and pushing down on the top to insert it into the computer's slot. Make sure to remove the back metal protector on the PCI slot if you have an IBM PC that comes with exterior covers.

IBM XT machines and other XT-compatible devices use a specific RAM partitioning scheme that enforces strict memory-management techniques on any application you run. Every early PC-compatible computer system that runs DOS, regardless of form factor, uses the following memory-management scheme when it launches:

• 0kB-640kB is set aside for conventional memory.
• 640kB-1024kb is reserved for the upper-memory area.
• 80286 computer systems reserve the next 64kB block as a high-memory area.
• Software drivers assign all higher XT memory cards to the extended-memory specification block.

• Keyboard: The way to connect a keyboard depends on the kind of processor your machine has. Most models featuring 80286-processor boards use a standard PC/AT keyboard adapter. XT and AT clones will also feature this standard XT keyboard connector. Later-model PS/2 model devices use the PS/2 jack, which allows you to connect an IBM Model M board to them.
• Monitor: Both vintage and contemporary monitors can be connected to vintage IBM computers that are not all-in-one models with attached monitors. While higher resolution monitors can be attached to these computers, the graphics card in the computer will drive the pixel size that the computer is capable of displaying with its software.

Xenix and DOS are the two most common OEM operating systems you'll find in these computers. On the original hard drives, you may have the ability to run multiple operating systems. You can install Xenix and DOS to the same hard drive if you create an active DOS partition for your standard IBM PC XT operating system and a secondary Unix partition for Microsoft Xenix on the same hard drive. A similar procedure will allow you to run this kind of microcomputer system software on larger pieces of IBM computer equipment.