Category Archives: PC architecture

The floppy controller evolution

Posted on May 26, 2011 by Michal Necasek

The floppy subsystem in PCs hadn’t mutated over time quite as much as, say, the hard disk subsystem, but prior to its extinction in the early 21st century, the floppy disk controller (FDC) did evolve noticeably. In the original IBM … Continue reading →

Posted in PC architecture | 14 Comments

The Fixed Disk Parameter Table

Posted on May 11, 2011 by Michal Necasek

The Fixed Disk Parameter Table, or FDPT, is a structure primarily used by the BIOS in IBM compatible computers, but is also of critical importance to some (especially older) operating systems which do not use the BIOS. The FDPT was … Continue reading →

Posted in BIOS, PC architecture, Virtualization | 3 Comments

Geometry Problems

Posted on May 11, 2011 by Michal Necasek

When introducing hard disk support in the PC/XT back in early 1983, IBM made a very unfortunate design decision: the information about drive geometry was exposed in the BIOS, and even worse, in the boot sector stored on the disk. SCSI … Continue reading →

Posted in BIOS, PC architecture, Virtualization | 2 Comments

The PC floppy subsystem

Posted on April 5, 2011 by Michal Necasek

The PC floppy subsystem, ubiquitous and indispensable until the early 21st century, suffered the typical fate of many “legacy” subsystems: The initial design was adequate, but did not adapt to newer and more complex hardware. With the original IBM PC, … Continue reading →

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